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Mitarai, Satoshi, Hiromi Watanabe, Yuichi Nakajima, Alexander F. Shchepetkin y James C. McWilliams. "Quantifying dispersal from hydrothermal vent fields in the western Pacific Ocean". Proceedings of the National Academy of Sciences 113, n.º 11 (29 de febrero de 2016): 2976–81. http://dx.doi.org/10.1073/pnas.1518395113.
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Hydrothermal vent fields in the western Pacific Ocean are mostly distributed along spreading centers in submarine basins behind convergent plate boundaries. Larval dispersal resulting from deep-ocean circulations is one of the major factors influencing gene flow, diversity, and distributions of vent animals. By combining a biophysical model and deep-profiling float experiments, we quantify potential larval dispersal of vent species via ocean circulation in the western Pacific Ocean. We demonstrate that vent fields within back-arc basins could be well connected without particular directionality, whereas basin-to-basin dispersal is expected to occur infrequently, once in tens to hundreds of thousands of years, with clear dispersal barriers and directionality associated with ocean currents. The southwest Pacific vent complex, spanning more than 4,000 km, may be connected by the South Equatorial Current for species with a longer-than-average larval development time. Depending on larval dispersal depth, a strong western boundary current, the Kuroshio Current, could bridge vent fields from the Okinawa Trough to the Izu-Bonin Arc, which are 1,200 km apart. Outcomes of this study should help marine ecologists estimate gene flow among vent populations and design optimal marine conservation plans to protect one of the most unusual ecosystems on Earth.
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LEE, YONG IL y GEORGE DeVRIES KLEIN. "Diagenesis of sandstones in the back-arc basins of the western Pacific Ocean". Sedimentology 33, n.º 5 (octubre de 1986): 651–75. http://dx.doi.org/10.1111/j.1365-3091.1986.tb01968.x.
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Chekhovich, V. D., A. N. Sukhov, M. V. Kononov y O. G. Sheremet. "Comparative geodynamics of Aleutian and Izu-Bonin-Mariana island-arc systems". Геотектоника, n.º 1 (1 de abril de 2019): 27–43. http://dx.doi.org/10.31857/s0016-853x2019127-43.
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Fulfilled comparative analysis of the Aleutian and Izu-Bonin-Marian island-arc systems structure and geodynamic development. Izu-Bonin-Maian island-arc systems situated along сontinental margin of Eurasia in the West of Pacific Ocean. The Aleutian island-arc system is situated between the North American and Eurasian continents. Aleutian and Izu-Bonin-Marian island-arc systems appeared to be of the same age. Both island-arc systems form autonomous Philippine and Beringia small lithospheric plates. Izu-Bonin-Marianas island-arc system formed on exclusively geodynamic interaction of oceanic plate and back-arc basins, with the main role of the Pacific subduction. Aleutian system at the initial stage was formed as a result from separation of the part of Pacific Cretaceous crust by Aleutian subduction zone.
The subsequent process of Aleutian system development was caused by geodynamics of movement of North American and Eurasian lithospheric plates. Pacific plate constant oblique subduction led to expansion of Aleutian island-arc system in the Western direction.
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SAUTYA, SABYASACHI, KONSTANTIN R. TABACHNICK y BABAN INGOLE. "First record of Hyalascus (Hexactinellida: Rossellidae) from the Indian Ocean, with description of a new species from a volcanic seamount in the Andaman Sea". Zootaxa 2667, n.º 1 (4 de noviembre de 2010): 64. http://dx.doi.org/10.11646/zootaxa.2667.1.5.
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Cubelio, Sherine Sonia, Shinji Tsuchida y Seiichi Watanabe. "New species ofMunidopsis(Decapoda: Anomura: Galatheidae) from hydrothermal vent areas of Indian and Pacific Oceans". Journal of the Marine Biological Association of the United Kingdom 88, n.º 1 (febrero de 2007): 111–17. http://dx.doi.org/10.1017/s0025315408000180.
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Two new species ofMunidopsisfrom the hydrothermal vent area, Kairei Field, Central Indian Ridge in the Indian Ocean and Forecast Vent Field, Mariana Back Arc Basin in the west Pacific are described and illustrated. Their affinities to closely related species are discussed. The number ofMunidopsisspecies associated to hydrothermal vents in the world oceans has increased to 16. The habitat of new species is briefly described and the pattern of abundance of vent associatedMunidopsisis briefly discussed.
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Kiel, Steffen. "A biogeographic network reveals evolutionary links between deep-sea hydrothermal vent and methane seep faunas". Proceedings of the Royal Society B: Biological Sciences 283, n.º 1844 (14 de diciembre de 2016): 20162337. http://dx.doi.org/10.1098/rspb.2016.2337.
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Deep-sea hydrothermal vents and methane seeps are inhabited by members of the same higher taxa but share few species, thus scientists have long sought habitats or regions of intermediate character that would facilitate connectivity among these habitats. Here, a network analysis of 79 vent, seep, and whale-fall communities with 121 genus-level taxa identified sedimented vents as a main intermediate link between the two types of ecosystems. Sedimented vents share hot, metal-rich fluids with mid-ocean ridge-type vents and soft sediment with seeps. Such sites are common along the active continental margins of the Pacific Ocean, facilitating connectivity among vent/seep faunas in this region. By contrast, sedimented vents are rare in the Atlantic Ocean, offering an explanation for the greater distinction between its vent and seep faunas compared with those of the Pacific Ocean. The distribution of subduction zones and associated back-arc basins, where sedimented vents are common, likely plays a major role in the evolutionary and biogeographic connectivity of vent and seep faunas. The hypothesis that decaying whale carcasses are dispersal stepping stones linking these environments is not supported.
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Tamayo*, Rodolfo A., René C. Maury*, Graciano P. Yumul, Mireille Polvé, Joseph Cotten, Carla B. Dimantala y Francia O. Olaguera. "Subduction-related magmatic imprint of most Philippine ophiolites: implications on the early geodynamic evolution of the Philippine archipelago". Bulletin de la Société Géologique de France 175, n.º 5 (1 de septiembre de 2004): 443–60. http://dx.doi.org/10.2113/175.5.443.
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Abstract The basement complexes of the Philippine archipelago include at least 20 ophiolites and ophiolitic complexes. These complexes are characterised by volcanic sequences displaying geochemical compositions similar to those observed in MORB, transitional MORB-island arc tholeiites and arc volcanic rocks originating from modern Pacific-type oceans, back-arc basins and island arcs. Ocean island basalt-like rocks are rarely encountered in the volcanic sequences. The gabbros from the ophiolites contain clinopyroxenes and plagioclases showing a wide range of XMg and An values, respectively. Some of these gabbros exhibit mineral chemistries suggesting their derivation from basaltic liquids formed from mantle sources that underwent either high degrees of partial melting or several partial melting episodes. Moreover, some of the gabbros display a crystallization sequence where orthopyroxene and clinopyroxene appeared before plagioclase. The major element compositions of coexisting orthopyroxenes and olivines from the mantle peridotites are consistent with low to high degrees of partial melting. Accessory spinels in these peridotites display a wide range of XCr values as well with some of them above the empirical upper limit of 0.6 often observed in most modern mid-oceanic ridge (MOR) mantle rocks. Co-existing olivines and spinels from the peridotites also exhibit compositions suggesting that they lastly equilibrated under oxidizing mantle conditions. The juxtaposition of volcanic rocks showing affinities with modern MOR and island arc environments suggests that most of the volcanic sequences in Philippine ophiolites formed in subduction-related geodynamic settings. Similarly, their associated gabbros and peridotites display mineralogical characteristics and mineral chemistries consistent with their derivation from modern supra-subduction zone-like environments. Alternatively, these rocks could have, in part, evolved in a supra-subduction zone even though they originated from a MOR-like setting. A simplified scenario regarding the early geodynamic evolution of the Philippines is proposed on the basis of the geochemical signatures of the ophiolites, their ages of formation and the ages and origins of the oceanic basins actually bounding the archipelago, including basins presumed to be now totally consumed. This scenario envisages the early development of the archipelago to be largely dominated by the opening and closing of oceanic basins. Fragments of these basins provided the substratum on top of which the Cretaceous to Recent volcanic arcs of the Philippines were emplaced.
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Suzuki, Yohey, Shigeaki Kojima, Takenori Sasaki, Masae Suzuki, Takashi Utsumi, Hiromi Watanabe, Hidetoshi Urakawa et al. "Host-Symbiont Relationships in Hydrothermal Vent Gastropods of the Genus Alviniconcha from the Southwest Pacific". Applied and Environmental Microbiology 72, n.º 2 (febrero de 2006): 1388–93. http://dx.doi.org/10.1128/aem.72.2.1388-1393.2006.
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ABSTRACT Hydrothermal vent gastropods of the genus Alviniconcha are unique among metazoans in their ability to derive their nutrition from chemoautotrophic γ- and ε-proteobacterial endosymbionts. Although host-symbiont relationships in Alviniconcha gastropods from the Central Indian Ridge in the Indian Ocean and the Mariana Trough in the Western Pacific have been studied extensively, host-symbiont relationships in Alviniconcha gastropods from the Southwest Pacific remain largely unknown. Phylogenetic analysis using mitochondrial cytochrome c oxidase subunit I gene sequences of host gastropods from the Manus, North Fiji, and Lau Back-Arc Basins in the Southwest Pacific has revealed a new host lineage in a Alviniconcha gastropod from the Lau Basin and the occurrence of the host lineage Alviniconcha sp. type 2 in the Manus Basin. Based on 16S rRNA gene sequences of bacterial endosymbionts, two γ-proteobacterial lineages and one ε-proteobacterial lineage were identified in the present study. The carbon isotopic compositions of the biomass and fatty acids of the gastropod tissues suggest that the γ- and ε-proteobacterial endosymbionts mediate the Calvin-Benson cycle and the reductive tricarboxylic acid cycle, respectively, for their chemoautotrophic growth. Coupling of the host and symbiont lineages from the three Southwest Pacific basins revealed that each of the Alviniconcha lineages harbors different bacterial endosymbionts belonging to either the γ- or ε-Proteobacteria. The host specificity exhibited in symbiont selection provides support for the recognition of each of the host lineages as a distinct species. The results from the present study also suggest the possibility that Alviniconcha sp. types 1 and 2 separately inhabit hydrothermal vent sites approximately 120 m apart in the North Fiji Basin and 500 m apart in the Manus Basin.
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Hinschberger, Florent, Jacques André Malod, Jean Pierre Réhault y Safri Burhanuddin. "Contribution of bathymetry and geomorphology to the geodynamics of the East Indonesian Seas". Bulletin de la Société Géologique de France 174, n.º 6 (1 de noviembre de 2003): 545–60. http://dx.doi.org/10.2113/174.6.545.
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Abstract Southeastern Indonesia is located at a convergent triple junction of 3 plates : the Pacific (including the Caro-line and Philippines plates), the Australian and the Southeast Asian plates (fig. 1). The age of the different basins : the North Banda Sea (Sula Basin), the South Banda Sea (Wetar and Damar Basins) and the Weber Trough has been debated for a long time. Their great depth was a reason to interpret them as remnants of oceanic domains either of Indian or Pacific ocean affinities. It has now been demonstrated from geochronological studies that these basins have formed during the Neogene [Réhault et al., 1994 ; Honthaas et al., 1998]. The crust has been sampled only in the Sula Basin, where basalts or trachyandesites with back-arc geochemical signatures have been dredged. Their ages range from 11.4 ± 1.15 to 7.33 ± 0.18 Ma [Réhault et al., 1994 ; Honthaas et al., 1998]. The study of the magnetic anomaly pattern of these basins confirms this interpretation and defines an age between 12.5 and 7.15 Ma for the North Banda Basin and between 6.5 to 3.5 Ma for the South Banda Basin [Hinschberger et al., 2000 ; Hinschberger et al., 2001]. Furthermore, the existence of volcanic arcs linked to subducted slabs suggests that these basins resulted from back-arc spreading and subduction slab roll-back. Lastly, the Weber Trough which exceeds 7 300 m in depth and is one of the deepest non subduction basins in the world, remains enigmatic. A compilation of existing bathymetric data allows us to present a new bathymetric map of the region (fig. 2 and 3). A comparison with the previous published maps [Mammerickx et al., 1976 ; Bowin et al., 1982] shows numerous differences at a local scale. This is especially true for the Banda Ridges or in the Sula Basin where new tectonic directions are expressed. In the North Banda Basin, the Tampomas Ridge, which was striking NE-SW in the previous maps, is actually NW-SE parallel to the West Buru Fracture Zone and to the Hamilton Fault scarp (fig. 6). This NW-SE direction represents the initial direction of rifting and oceanic spreading. In this basin, only the southeastern rifted margin morphology is preserved along the Sinta Ridges. The basin is presently involved in an overall compressional motion and its buckled and fractured crust is subducted westwards beneath East Sulawesi (fig. 4a, 5 and 6). The northern border of the North Banda Basin is reactivated into sinistral transcurrent motion in the South Sula Fracture Zone continued into the Matano fault in Sulawesi. The South Banda Sea Basin is divided in two parts, the Wetar and Damar Basins with an eastward increase in depth. The Wetar and Damar Basins are separated by the NNW-SSE Gunung Api Ridge, characterized by volcanoes, a deep pull apart basin and active tectonics on its eastern flank (fig. 4b and 7). This ridge is interpreted as a large sinistral strike-slip fracture zone which continues across the Banda Ridges and bends towards NW south of Sinta Ridge. The Banda Ridges region, separating the North Banda Basin from the southern Banda Sea (fig. 5 and 7), is another place where many new morphological features are now documented. The Sinta Ridge to the north is separated from Buru island by the South Buru Basin which may constitute together with the West Buru Fracture Zone a large transcurrent lineament striking NW-SE. The central Rama Ridge is made of 2 narrow ridges striking NE-SW with an « en-echelon » pattern indicating sinistral strike slip comparable to the ENE-WSW strike-slip faulting evidenced by focal mechanisms in the northern border of the Damar Basin [Hinschberger, 2000]. Dredging of Triassic platform rocks and metamorphic basement on the Sinta and Rama Ridges suggests that they are fragments of a continental block [Silver et al., 1985 ; Villeneuve et al., 1994 ; Cornée et al., 1998]. The Banda Ridges are fringed to the south by a volcanic arc well expressed in the morphology : the Nieuwerkerk-Emperor of China and the Lucipara volcanic chains whose andesites and arc basalts have been dated between 8 and 3.45 Ma [Honthaas et al., 1998]. Eastern Indonesia deep oceanic basins are linked to the existence of 2 different subduction zones expressed by 2 different downgoing slabs and 2 volcanic arcs : the Banda arc and the Seram arc [Cardwell et Isacks, 1978 ; Milsom, 2001]. They correspond respectively to the termination of the Australian subduction and to the Bird’s head (Irian Jaya) subduction under Seram (fig. 5). Our bathymetric study helps to define the Seram volcanic arc which follows a trend parallel to the Seram Trench from Ambelau island southeast of Buru to the Banda Island (fig. 2 and 5). A new volcanic seamount discovered in the southeast of Buru (location of dredge 401 in figure 7) and a large volcano in the Pisang Ridge (location of dredge 403 in figure 7 and figure 8) have been surveyed with swath bathymetry. Both show a sub-aerial volcanic morphology and a further subsidence evidenced by the dredging of reefal limestones sampled at about 3000 m depth on their flank. We compare the mean basement depths corrected for sediment loading for the different basins (fig. 9). These depths are about 5 000 m in the Sula Basin, 4 800 m in the Wetar basin and 5 100 m in the Damar basin. These values plot about 1 000 m below the age-depth curve for the back-arc basins [Park et al., 1990] and about 2000 m below the Parsons and Sclater’s curve for the oceanic crust [Parsons et Sclater, 1977]. More generally, eastern Indonesia is characterized by large vertical motions. Strong subsidence is observed in the deep basins and in the Banda Ridges. On the contrary, large uplifts characterize the islands with rates ranging between 20 to 250 cm/kyr [De Smet et al., 1989a]. Excess subsidence in the back-arc basins has been attributed to large lateral heat loss due to their small size [Boerner et Sclater, 1989] or to the presence of cold subducting slabs. In eastern Indonesia, these mechanisms can explain only a part of the observed subsidence. It is likely that we have to take into account the tectonic forces linked to plate convergence. This is supported by the fact that uplift motions are clearly located in the area of active collision. In conclusion, the bathymetry and morphology of eastern Indonesian basins reveal a tectonically very active region where basins opened successively in back-arc, intra-arc and fore-arc situation in a continuous convergent geodynamic setting.
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DeVries Klein, George. "The Control of Depositional Depth, Tectonic Uplift, and Volcanism on Sedimentation Processes in the Back-Arc Basins of the Western Pacific Ocean". Journal of Geology 93, n.º 1 (enero de 1985): 1–25. http://dx.doi.org/10.1086/628916.
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Yang, Jin-Shu, Bo Lu, Dian-Fu Chen, Yan-Qin Yu, Fan Yang, Hiromichi Nagasawa, Shinji Tsuchida, Yoshihiro Fujiwara y Wei-Jun Yang. "When Did Decapods Invade Hydrothermal Vents? Clues from the Western Pacific and Indian Oceans". Molecular Biology and Evolution 30, n.º 2 (16 de octubre de 2012): 305–9. http://dx.doi.org/10.1093/molbev/mss224.
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Abstract Hydrothermal vents are typically located in midocean ridges and back-arc basins and are usually generated by the movement of tectonic plates. Life thrives in these environments despite the extreme conditions. In addition to chemoautotrophic bacteria, decapod crustaceans are dominant in many of the hydrothermal vents discovered to date. Contrary to the hypothesis that these species are remnants of relic fauna, increasing evidence supports the notion that hydrothermal vent decapods have diversified in more recent times with previous research attributing the origin of alvinocarid shrimps to the Miocene. This study investigated seven representative decapod species from four hydrothermal vents throughout the Western Pacific and Indian Oceans. A partitioned mix-model phylogenomic analysis of mitochondrial DNA produced a consistent phylogenetic topology of these vent-endemic species. Additionally, molecular dating analysis calibrated using multiple fossils suggested that both bythograeid crabs and alvinocarid shrimps originated in the late Mesozoic and early Cenozoic. Although of limited sampling, our estimates support the extinction/repopulation hypothesis, which postulates recent diversification times for most hydrothermal vent species due to their mass extinction by global deep-water anoxic/dysoxic events during the Late Cretaceous and Early Tertiary. The continental-derived property of the West Pacific province is compatible with the possibility that vent decapods diversified from ancestors from shallow-water regions such as cold seeps. Our results move us a step closer toward understanding the evolutionary origin of hydrothermal vent species and their distribution in the Western Pacific–Indian Ocean Region.
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Southward, E. C. "Three new species of Pogonophora, including two vestimentiferans, from hydrothermal sites in the Lau Back-arc Basin (Southwest Pacific Ocean)". Journal of Natural History 25, n.º 4 (agosto de 1991): 859–81. http://dx.doi.org/10.1080/00222939100770571.
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Hall, Robert. "The subduction initiation stage of the Wilson cycle". Geological Society, London, Special Publications 470, n.º 1 (19 de febrero de 2018): 415–37. http://dx.doi.org/10.1144/sp470.3.
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AbstractIn the Wilson cycle, there is a change from an opening to a closing ocean when subduction begins. Subduction initiation is commonly identified as a major problem in plate tectonics and is said to be nowhere observable, yet there are many young subduction zones at the west Pacific margins and in eastern Indonesia. Few studies have considered these examples. Banda subduction developed by the eastwards propagation of the Java trench into an oceanic embayment by tearing along a former ocean–continent boundary. The earlier subducted slab provided the driving force to drag down unsubducted oceanic lithosphere. Although this process may be common, it does not account for young subduction zones near Sulawesi at different stages of development. Subduction began there at the edges of ocean basins, not at former spreading centres or transforms. It initiated at a point where there were major differences in elevation between the ocean floor and the adjacent hot, weak and thickened arc/continental crust. The age of the ocean crust appears to be unimportant. A close relationship with extension is marked by the dramatic elevation of land, the exhumation of deep crust and the spectacular subsidence of basins, raising questions about the time required to move from no subduction to active subduction, and how initiation can be identified in the geological record.
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Monger, James W. H. "Canadian Cordilleran tectonics: from geosynclines to crustal collage". Canadian Journal of Earth Sciences 30, n.º 2 (1 de febrero de 1993): 209–31. http://dx.doi.org/10.1139/e93-019.
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The major contributions by the Geological Survey of Canada in the Canadian Cordillera—systematic mapping and definition of the regional geological framework—led directly to tectonic syntheses that attempted to explain its origin. From the late 1800's until the 1960's, Cordilleran mountain building was viewed as the end result of geosynclinal deposition. Early workers felt that a connection existed between mountain building and the Pacific basin, but its nature was never clear because little was known about ocean basins and their relationships to continental margins. In the 1950's, the nature of the oceanic lithosphere and ocean–continent relationships became better known; the knowledge led to formulation of the plate-tectonic hypothesis in the 1960's, a time fortuitously coinciding with completion, by the Survey, of most of the regional geological mapping (scale 1: 250 000). Geosynclinal rock units were reinterpreted in terms of their possible modern analogues (oceanic, island-arc, continental shelf – slope assemblages) and paleontological and paleomagnetic studies were used to support a mobilistic view of Cordilleran paleogeography, rather than the relatively fixed paleogeography tacitly assumed in earlier interpretations. In contrast with deterministic geosynclinal theory, it was recognized that plate-tectonic processes applied over a long time have enormous potential to create disorder; the result is an orogenic collage to be analyzed as a series of time – space events each of whose geodynamic settings may have been very different from one another. This aspect is especially important in the long-lived Cordillera, which was initiated as a continent–ocean boundary in latest Proterozoic time, evolved through the entire Phanerozoic, and today is a convergent-transform continen – ocean plate margin. Interactions between various oceanic plates and the North American plate, shown by the Cordilleran record of accretionary complexes, as well as results of possible arc–continent collisions and continental margin arc magmatism, formed new continental crust.
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Ishii, M., R. A. Feely, K. B. Rodgers, G. H. Park, R. Wanninkhof, D. Sasano, H. Sugimoto et al. "Air–sea CO<sub>2</sub> flux in the Pacific Ocean for the period 1990–2009". Biogeosciences 11, n.º 3 (6 de febrero de 2014): 709–34. http://dx.doi.org/10.5194/bg-11-709-2014.
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Abstract. Air–sea CO2 fluxes over the Pacific Ocean are known to be characterized by coherent large-scale structures that reflect not only ocean subduction and upwelling patterns, but also the combined effects of wind-driven gas exchange and biology. On the largest scales, a large net CO2 influx into the extratropics is associated with a robust seasonal cycle, and a large net CO2 efflux from the tropics is associated with substantial interannual variability. In this work, we have synthesized estimates of the net air–sea CO2 flux from a variety of products, drawing upon a variety of approaches in three sub-basins of the Pacific Ocean, i.e., the North Pacific extratropics (18–66° N), the tropical Pacific (18° S–18° N), and the South Pacific extratropics (44.5–18° S). These approaches include those based on the measurements of CO2 partial pressure in surface seawater (pCO2sw), inversions of ocean-interior CO2 data, forward ocean biogeochemistry models embedded in the ocean general circulation models (OBGCMs), a model with assimilation of pCO2sw data, and inversions of atmospheric CO2 measurements. Long-term means, interannual variations and mean seasonal variations of the regionally integrated fluxes were compared in each of the sub-basins over the last two decades, spanning the period from 1990 through 2009. A simple average of the long-term mean fluxes obtained with surface water pCO2 diagnostics and those obtained with ocean-interior CO2 inversions are −0.47 ± 0.13 Pg C yr−1 in the North Pacific extratropics, +0.44 ± 0.14 Pg C yr−1 in the tropical Pacific, and −0.37 ± 0.08 Pg C yr−1 in the South Pacific extratropics, where positive fluxes are into the atmosphere. This suggests that approximately half of the CO2 taken up over the North and South Pacific extratropics is released back to the atmosphere from the tropical Pacific. These estimates of the regional fluxes are also supported by the estimates from OBGCMs after adding the riverine CO2 flux, i.e., −0.49 ± 0.02 Pg C yr−1 in the North Pacific extratropics, +0.41 ± 0.05 Pg C yr−1 in the tropical Pacific, and −0.39 ± 0.11 Pg C yr−1 in the South Pacific extratropics. The estimates from the atmospheric CO2 inversions show large variations amongst different inversion systems, but their median fluxes are consistent with the estimates from climatological pCO2sw data and pCO2sw diagnostics. In the South Pacific extratropics, where CO2 variations in the surface and ocean interior are severely undersampled, the difference in the air–sea CO2 flux estimates between the diagnostic models and ocean-interior CO2 inversions is larger (0.18 Pg C yr−1). The range of estimates from forward OBGCMs is also large (−0.19 to −0.72 Pg C yr−1). Regarding interannual variability of air–sea CO2 fluxes, positive and negative anomalies are evident in the tropical Pacific during the cold and warm events of the El Niño–Southern Oscillation in the estimates from pCO2sw diagnostic models and from OBGCMs. They are consistent in phase with the Southern Oscillation Index, but the peak-to-peak amplitudes tend to be higher in OBGCMs (0.40 ± 0.09 Pg C yr−1) than in the diagnostic models (0.27 ± 0.07 Pg C yr−1).
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Ishii, M., R. A. Feely, K. B. Rodgers, G. H. Park, R. Wanninkhof, D. Sasano, H. Sugimoto et al. "Air-sea CO<sub>2</sub> flux in the Pacific Ocean for the period 1990–2009". Biogeosciences Discussions 10, n.º 7 (19 de julio de 2013): 12155–216. http://dx.doi.org/10.5194/bgd-10-12155-2013.
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Abstract. Air-sea CO2 fluxes over the Pacific Ocean are known to be characterized by coherent large-scale structures that reflect not only ocean subduction and upwelling patterns, but also the combined effects of wind-driven gas exchange and biology. On the largest scales, a large net CO2 influx into the extra-tropics is associated with a robust seasonal cycle, and a large net CO2 efflux from the tropics is associated with substantial inter-annual variability. In this work, we have synthesized estimates of the net air-sea CO2 flux from a variety of products drawing upon a variety of approaches in three sub-basins of the Pacific Ocean, i.e., the North Pacific extra-tropics (18° N–66° N), the tropical Pacific (18° S–18° N), and the South Pacific extra-tropics (44.5° S–18° S). These approaches include those based on the measurements of CO2 partial pressure in surface seawater (pCO2sw), inversions of ocean interior CO2 data, forward ocean biogeochemistry models embedded in the ocean general circulation models (OBGCMs), a model with assimilation of pCO2sw data, and inversions of atmospheric CO2 measurements. Long-term means, inter-annual variations and mean seasonal variations of the regionally-integrated fluxes were compared in each of the sub-basins over the last two decades, spanning the period from 1990 through 2009. A simple average of the long-term mean fluxes obtained with surface water pCO2 diagnostics and those obtained with ocean interior CO2 inversions are –0.47 ± 0.13 Pg C yr–1 in the North Pacific extra-tropics, +0.44 ± 0.14 Pg C yr–1 in the tropical Pacific, and –0.37 ± 0.08 Pg C yr–1 in the South Pacific extra-tropics, where positive fluxes are into the atmosphere. This suggests that approximately half of the CO2 taken up over the North and South Pacific extra-tropics is released back to the atmosphere from the tropical Pacific. These estimates of the regional fluxes are also supported by the estimates from OBGCMs after adding the riverine CO2 flux, i.e., –0.49 ± 0.02 Pg C yr–1 in the North Pacific extra-tropics, +0.41 ± 0.05 Pg C yr–1 in the tropical Pacific, and –0.39 ± 0.11 Pg C yr–1 in the South Pacific extra-tropics. The estimates from the atmospheric CO2 inversions show large variations amongst different inversion systems, but their median fluxes are consistent with the estimates from climatological pCO2sw data and pCO2sw diagnostics. In the South Pacific extra-tropics, where CO2 variations in the surface and ocean interior are severely under-sampled, the difference in the air-sea CO2 flux estimates between the diagnostic models and ocean interior CO2 inversions is larger (0.18 Pg C yr–1). The range of estimates from forward OBGCMs is also large (−0.19 to −0.72 Pg C yr–1). Regarding inter-annual variability of air-sea CO2 fluxes, positive and negative anomalies are evident in the tropical Pacific during the cold and warm events of the El Niño Southern Oscillation in the estimates from pCO2sw diagnostic models and from OBGCMs. They are consistent in phase with the Southern Oscillation Index, but the peak-to-peak amplitudes tend to be higher in OBGCMs (0.40 ± 0.09 Pg C yr–1) than in the diagnostic models (0.27 ± 0.07 Pg C yr–1).
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Hatch, Avery S., Haebin Liew, Stéphane Hourdez y Greg W. Rouse. "Hungry scale worms: Phylogenetics of Peinaleopolynoe (Polynoidae, Annelida), with four new species". ZooKeys 932 (12 de mayo de 2020): 27–74. http://dx.doi.org/10.3897/zookeys.932.48532.
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Polynoidae Kinberg, 1856 has five branchiate genera: Branchipolynoe Pettibone, 1984, Branchinotogluma Pettibone, 1985, Branchiplicatus Pettibone, 1985, Peinaleopolynoe Desbruyères & Laubier, 1988, and Thermopolynoe Miura, 1994, all native to deep-sea, chemosynthetic-based habitats. Of these, Peinaleopolynoe has two accepted species; Peinaleopolynoe sillardi Desbruyères & Laubier, 1988 (Atlantic Ocean) and Peinaleopolynoe santacatalina Pettibone, 1993 (East Pacific Ocean). The goal of this study was to assess the phylogenetic position of Peinaleopolynoe, utilizing DNA sequences from a broad sampling of deep-sea polynoids. Representatives from all five branchiate genera were included, several species of which were sampled from near the type localities; Branchinotogluma sandersi Pettibone, 1985 from the Galápagos Rift (E/V “Nautilus”); Peinaleopolynoe sillardi from organic remains in the Atlantic Ocean; Peinaleopolynoe santacatalina from a whalefall off southern California (R/V “Western Flyer”) and Thermopolynoe branchiata Miura, 1994 from Lau Back-Arc Basin in the western Pacific (R/V “Melville”). Phylogenetic analyses were conducted using mitochondrial (COI, 16S rRNA, and CytB) and nuclear (18S rRNA, 28S rRNA, and H3) genes. The analyses revealed four new Peinaleopolynoe species from the Pacific Ocean that are formally described here: Peinaleopolynoe orphanae Hatch & Rouse, sp. nov., type locality Pescadero Basin in the Gulf of California, Mexico (R/V “Western Flyer”); Peinaleopolynoe elvisi Hatch & Rouse, sp. nov. and Peinaleopolynoe goffrediae Hatch & Rouse, sp. nov., both with a type locality in Monterey Canyon off California (R/V “Western Flyer”) and Peinaleopolynoe mineoi Hatch & Rouse, sp. nov. from Costa Rica methane seeps (R/V “Falkor”). In addition to DNA sequence data, the monophyly of Peinaleopolynoe is supported by the presence of ventral papillae on segments 12–15. The results also demonstrated the paraphyly of Branchinotogluma and Lepidonotopodium Pettibone, 1983 and taxonomic revision of these genera is required. We apply the subfamily name Lepidonotopodinae Pettibone 1983, for the clade comprised of Branchipolynoe, Branchinotogluma, Bathykurila, Branchiplicatus, Lepidonotopodium, Levensteiniella Pettibone, 1985, Thermopolynoe, and Peinaleopolynoe.
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Primeau, François. "Long Rossby Wave Basin-Crossing Time and the Resonance of Low-Frequency Basin Modes". Journal of Physical Oceanography 32, n.º 9 (1 de septiembre de 2002): 2652–65. http://dx.doi.org/10.1175/1520-0485-32.9.2652.
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Abstract The ability of long-wave low-frequency basin modes to be resonantly excited depends on the efficiency with which energy fluxed onto the western boundary can be transmitted back to the eastern boundary. This efficiency is greatly reduced for basins in which the long Rossby wave basin-crossing time is latitude dependent. In the singular case where the basin-crossing time is independent of latitude, the amplitude of resonantly excited long-wave basin modes grows without bound except for the effects of friction. The speed of long Rossby waves is independent of latitude for quasigeostrophic dynamics, and the rectangular basin geometry often used for theoretical studies of the wind-driven ocean circulation is such a singular case for quasigeostrophic dynamics. For more realistic basin geometries, where only a fraction of the energy incident on the western boundary can be transmitted back to the eastern boundary, the modes have a finite decay rate that in the limit of weak friction is independent of the choice of frictional parameters. Explicit eigenmode computations for a basin geometry similar to the North Pacific but closed along the equator yield basin modes sufficiently weakly damped that they could be resonantly excited.
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Southward, E. C. y S. V. Galkin. "A new vestimentiferan (Pogonophora: Obturata) from hydrothermal vent fields in the Manus Back-arc Basin (Bismarck Sea, Papua New Guinea, Southwest Pacific Ocean)". Journal of Natural History 31, n.º 1 (enero de 1997): 43–55. http://dx.doi.org/10.1080/00222939700770041.
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Lau, Ngar-Cheung, Ants Leetmaa y Mary Jo Nath. "Attribution of Atmospheric Variations in the 1997–2003 Period to SST Anomalies in the Pacific and Indian Ocean Basins". Journal of Climate 19, n.º 15 (1 de agosto de 2006): 3607–28. http://dx.doi.org/10.1175/jcli3813.1.
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Abstract The individual impacts of sea surface temperature (SST) anomalies in the deep tropical eastern–central Pacific (DTEP) and Indo-western–central Pacific (IWP) on the evolution of the observed global atmospheric circulation during the 1997–2003 period have been investigated using a new general circulation model. Ensemble integrations were conducted with monthly varying SST conditions being prescribed separately in the DTEP sector, the IWP sector, and throughout the World Ocean. During the 1998–2002 subperiod, when prolonged La Niña conditions occurred in DTEP and the SST in IWP was above normal, the simulated midlatitude atmospheric responses to SST forcing in the DTEP and IWP sectors reinforced each other. The anomalous geopotential height ridges at 200 mb in the extratropics of both hemispheres exhibited a distinct zonal symmetry. This circulation change was accompanied by extensive dry and warm anomalies in many regions, including North America. During the 1997–98 and 2002–03 El Niño events, the SST conditions in both DTEP and IWP were above normal, and considerable cancellations were simulated between the midlatitude responses to the oceanic forcing from these two sectors. The above findings are contrasted with those for the 1953–58 and 1972–77 periods, which were characterized by analogous SST developments in DTEP, but by cold conditions in IWP. It is concluded that a warm anomaly in IWP and a cold anomaly in DTEP constitute the optimal SST configuration for generating zonally elongated ridges in the midlatitudes. Local diagnoses indicate that the imposed SST anomaly alters the strength of the zonal flow in certain longitudinal sectors, which influences the behavior of synoptic-scale transient eddies farther downstream. The modified eddy momentum transports in the regions of eddy activity in turn feed back on the local mean flow, thus contributing to its zonal elongation. These results are consistent with the inferences drawn from zonal mean analyses, which accentuate the role of the eddy-induced circulation on the meridional plane.
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Zhang, Xinchang, Yuejun Wang, Ron Harris, Yi Yan y Yi Zheng. "Discovery of Middle–Late Devonian and Early Permian magmatic events in East Asia and their implication for the Indosinian orogeny in South China: Insights from the sedimentary record". GSA Bulletin 131, n.º 9-10 (28 de febrero de 2019): 1519–36. http://dx.doi.org/10.1130/b35032.1.
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Abstract Whether the driver of the Indosinian orogeny in the South China block was related to the evolution of the Paleotethyan Ocean or the Paleo-Pacific Ocean has been a point of much debate. We applied detrital zircon U-Pb dating to Permian–Triassic sedimentary rocks from South China to trace sediment provenance and to further test these models. Our results, combined with other published data from the Pingxiang, Youjiang, Yong’an, and Yongding Basins, show that 400–350 Ma and 300–260 Ma zircon grains are ubiquitous throughout the entirety of southern South China. This indicates regional magmatic events as potential sources. The discovery of Middle–Late Devonian and Early Permian igneous rocks, tuffs, and volcaniclastic rocks in Southeast Asia and Hainan Island implies the presence of two magmatic events (400–350 Ma and 300–260 Ma) within or beyond the southern margin of South China. This information, together with the mostly negative εHf(t) values of 400–350 Ma and 300–260 Ma zircon grains, arc-like geochemical signatures of the possible source rocks, and the regional geology of East Asia, suggests that they originated from sources related to Paleotethyan and even Proto-Tethyan subduction. Thus, Permian–Triassic sedimentation and the Indosinian orogeny in South China were largely controlled by the evolution of the Tethyan Ocean.
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Spörli, K. B. "Tectonic Controls on Cenozoic Sedimentation in the North Island New Zealand". Energy Exploration & Exploitation 6, n.º 2 (abril de 1988): 104–17. http://dx.doi.org/10.1177/014459878800600204.
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Cenozoic deformation of the North Island was dominated by the “closure” of the Challenger Rift and the establishment of the presently active subduction system. The initiation of subduction-related volcanic chains and their subsequent migration influenced the source of clastic material deposited in the Neogene basins. Uplift patterns, shoreline and drainage configurations were governed by complex 3-D distortion of the transition between the Alpine Fault system in the south and the Hikurangi through subduction system in the north. Along the Pacific side of the island, in Northland, some “piggy back” basins were formed on allochthonous pockets of sediments involved in obduction of ocean floor rocks onto the North island. Clockwise rotation on the east coast region and alternate coupling and decoupling across the subduction thrust created short-lived forearc basins. Axial ranges, and derivation of gravels from them are younger than 1 m y B.P. A very young, still active cross structure due to oblique subduction led to the formation of South Taranaki Bight, caused differences in the width of the axial ranges along their length and may be the reason for the peculiar coastal indentation of Hawke Bay.
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Storey, Bryan C. y Roi Granot. "Chapter 1.1 Tectonic history of Antarctica over the past 200 million years". Geological Society, London, Memoirs 55, n.º 1 (2021): 9–17. http://dx.doi.org/10.1144/m55-2018-38.
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AbstractThe tectonic evolution of Antarctica in the Mesozoic and Cenozoic eras was marked by igneous activity that formed as a result of simultaneous continental rifting and subduction processes acting during the final stages of the southward drift of Gondwana towards the South Pole. For the most part, continental rifting resulted in the progressive disintegration of the Gondwana supercontinent from Middle Jurassic times to the final isolation of Antarctica at the South Pole following the Cenozoic opening of the surrounding ocean basins, and the separation of Antarctica from South America and Australia. The initial rifting into East and West Gondwana was proceeded by emplacement of large igneous provinces preserved in present-day South America, Africa and Antarctica. Continued rifting within Antarctica did not lead to continental separation but to the development of the West Antarctic Rift System, dividing the continent into the East and West Antarctic plates, and uplift of the Transantarctic Mountains. Motion between East and West Antarctica has been accommodated by a series of discrete rifting pulses with a westward shift and concentration of the motion throughout the Cenozoic leading to crustal thinning, subsidence, elevated heat flow conditions and rift-related magmatic activity. Contemporaneous with the disintegration of Gondwana and the isolation of Antarctica, subduction processes were active along the palaeo-Pacific margin of Antarctica recorded by magmatic arcs, accretionary complexes, and forearc and back-arc basin sequences. A low in magmatic activity between 156 and 142 Ma suggests that subduction may have ceased during this time. Today, following the gradual cessation of the Antarctic rifting and surrounding subduction, the Antarctic continent is situated close to the centre of a large Antarctic Plate which, with the exception of an active margin on the northern tip of the Antarctic Peninsula, is surrounded by active spreading ridges.
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Smith, Alan D. y Richard StJ Lambert. "Nd, Sr, and Pb isotopic evidence for contrasting origins of late Paleozoic volcanic rocks from the Slide Mountain and Cache Creek terranes, south-central British Columbia". Canadian Journal of Earth Sciences 32, n.º 4 (1 de abril de 1995): 447–59. http://dx.doi.org/10.1139/e95-038.
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The Slide Mountain and Cache Creek terranes are two prominent oceanic sutures in the Canadian Cordillera. Petrological and isotopic variations between volcanic rocks in these terranes support earlier interpretations from stratigraphic evidence that the Slide Mountain terrane represents the remnant of a late Paleozoic basin situated marginal to western North America, whereas the Cache Creek terrane represents a remnant of a much larger, open-ocean basin. Slide Mountain terrane volcanic rocks, represented by Late Pennsylvanian basalts of the Fennell Formation, resemble normal mid-oceanic ridge basalts but possess an unusual kaersutite- or augite-dominated mineralogy. Their εNd(300 Ma) values of +7.7 to +10.2 are among the highest observed for Paleozoic basalts. The hydrous mineralogy can be reconciled with eruption on a spreading ridge in either a back-arc or marginal basin setting. The latter is preferred from Pb isotope compositions (206Pb/204Pb = 17.7–18.5, 207Pb/204Pb = 15.51–15.61, 208Pb/204Pb = 37.2–38.8), which suggest exchange with high Th/U continental-derived sediment during hydrothermal alteration. Volcanic rocks, probably middle Mississippian, in the Bonaparte subterrane of the Cache Creek terrane include picrites and basalts belonging to a within-plate tholeiite suite. The intraplate suite broadly resembles Hawaiian basalts in major and trace element composition. However, moderate positive εNd values (εNd(340 Ma) +4.2 to +5.6) and a transition toward DUPAL signatures in Pb isotopic composition (206Pb/204Pb = 18.1–19.1, 207Pb/204Pb = 15.54–15.61, 208Pb/204Pb = 37.8–38.6) are features more similar to volcanic rocks from modern South Pacific ocean islands. Basaltic andesite and andesitic tuffs, also found in the Bonaparte subterrane, are tentatively correlated with Late Triassic to Early Jurassic low-K tholeiitic volcanic rocks of the Nicola Group on the Quesnel terrane.
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Portela, Esther, Nicolas Kolodziejczyk, Christophe Maes y Virginie Thierry. "Interior Water-Mass Variability in the Southern Hemisphere Oceans during the Last Decade". Journal of Physical Oceanography 50, n.º 2 (febrero de 2020): 361–81. http://dx.doi.org/10.1175/jpo-d-19-0128.1.
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AbstractUsing an Argo dataset and the ECCOv4 reanalysis, a volume budget was performed to address the main mechanisms driving the volume change of the interior water masses in the Southern Hemisphere oceans between 2006 and 2015. The subduction rates and the isopycnal and diapycnal water-mass transformation were estimated in a density–spiciness (σ–τ) framework. Spiciness, defined as thermohaline variations along isopycnals, was added to the potential density coordinates to discriminate between water masses spreading on isopycnal layers. The main positive volume trends were found to be associated with the Subantarctic Mode Waters (SAMW) in the South Pacific and South Indian Ocean basins, revealing a lightening of the upper waters in the Southern Hemisphere. The SAMW exhibits a two-layer density structure in which subduction and diapycnal transformation from the lower to the upper layers accounted for most of the upper-layer volume gain and lower-layer volume loss, respectively. The Antarctic Intermediate Waters, defined here between the 27.2 and 27.5 kg m−3 isopycnals, showed the strongest negative volume trends. This volume loss can be explained by their negative isopyncal transformation southward of the Antarctic Circumpolar Current into the fresher and colder Antarctic Winter Waters (AAWW) and northward into spicier tropical/subtropical Intermediate Waters. The AAWW is destroyed by obduction back into the mixed layer so that its net volume change remains nearly zero. The proposed mechanisms to explain the transformation within the Intermediate Waters are discussed in the context of Southern Ocean dynamics. The σ–τ decomposition provided new insight on the spatial and temporal water-mass variability and driving mechanisms over the last decade.
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IVANENKO, VIATCHESLAV N., PEDRO MARTÍNEZ ARBIZU y JENS STECHER. "Copepods of the family Dirivultidae (Siphonostomatoida) from deep-sea hydrothermal vent fields on the Mid-Atlantic Ridge at 14ºN and 5ºS". Zootaxa 1277, n.º 1 (31 de julio de 2006): 1. http://dx.doi.org/10.11646/zootaxa.1277.1.1.
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Five species of three genera of Dirivultidae Humes and Dojiri, 1980 were found at deep-sea hydrothermal vent fields on the Mid-Atlantic Ridge, at the Logachev-1 field at 14ºN and at two new sites (Turtle Pits and Red Lion) explored at 5ºS. The copepods were collected with a Remotely Operated Vehicle (ROV Quest 4000) and Video Controlled Grab, operated from the R/V Meteor during two cruises (M60/3 and M64/1) conducted in 2004 and 2005 at depths 2992–3048 m. The male of Stygiopontius lomonosovi n. sp. from the Logachev field shares a medioventrally prolonged syncoxa of the maxilliped with S. mirus Humes, 1996 and S. latulus Humes, 1996 from the Snake Pit at 23ºN of the Mid-Atlantic Ridge, but differs from them in having two, instead of three, outer spines on the distal exopodal segment of leg 4. Aphotopontius atlanteus Humes, 1996 previously known from the Lucky Strike and the Menez Gwen sites at 37°N and Rimipontius mediospinifer Humes, 1996 known from three sites (Logachev, Snake Pit, and Broken Spur at 29°N) are recorded from the Logachev field. Stygiopontius pectinatus Humes, 1987 previously recorded from the Mid-Atlantic Ridge hydrothermal vent fields TAG (26°N), Snake Pit, Broken Spur (29°N), and from the Mariana Back-Arc Basin of the Pacific Ocean and Stygiopontius cladarus Humes, 1996 previously known only from Snake Pit and Broken Spur, were found associated with alvinocaridid shrimps (Rimicaris sp.) from the hydrothermal vent field at 5ºS. The discovery of dirivultids at 5ºS represents the first record of copepods from a deep-sea hydrothermal vent southward of the Logachev field in the Atlantic Ocean.
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Sato, K., S. V. Kovalenko, N. P. Romanovsky, M. Nedachi, N. V. Berdnikov y T. Ishihara. "Crustal control on the redox state of granitoid magmas: tectonic implications from the granitoid and metallogenic provinces in the circum-Japan Sea Region". Earth and Environmental Science Transactions of the Royal Society of Edinburgh 95, n.º 1-2 (marzo de 2004): 319–37. http://dx.doi.org/10.1017/s0263593300001103.
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ABSTRACTFelsic magmatism has occurred over a large region of East Asia since Jurassic times and has provided important mineral resources such as tin, tungsten, base metals and gold. The circum-Japan Sea region preserves various geological records of active continental margins, including Jurassic to Early Tertiary magmatic arcs and subduction zones and pre-Jurassic continental basements, which were separated by the opening of the Japan Sea during the Miocene. The felsic magmatism in this region shows a wide variation in terms of redox state and related mineralisation, encompassing east–west contrasts around the Pacific Ocean. A review of granitoids and associated ore deposits in this region indicates that the character of the crust, sedimentary versus igneous, is an essential factor to control the redox state, and a tectonic setting may be an additional factor in some cases.The reduced-type granitoids, characterised by tin mineralisation, were generated in carbonbearing sedimentary crust which was composed mainly of accretionary complex material and not influenced by previous magmatism. Involvement of sedimentary materials is corroborated by oxygen, sulphur and strontium isotope data. The oxidised-type granitoids, characterised by gold or molybdenum mineralisation, were generated in igneous crust which was depleted in reducing agents as a result of previous magmatism. Granitoid magmatism in a given area tends to become more oxidised with time.Jurassic accretionary complexes in East Asia are thought to have been largely displaced from the original place of accretion and stacked up against the northeastern margin in the Khingan and Sikhote–Alin Mountains. This region, dominated by sedimentary crust, was subsequently subjected to Cretaceous felsic magmatism and converted to a large province of reduced-type granitoids and tin–tungsten mineralisation. Diverse geodynamic processes, including the change of the arc-trench system, the creation and collapse of the back-arc basin and the collision of continents, may have prepared many favourable sites for the generation of reduced-type granitoids in northeast Asia. These processes may have resulted in a remarkable contrast with the Pacific margin of North America, where repeated arc magmatism during the Mesozoic formed granitoid batholiths of the oxidised-type.The granitoid types may also be controlled by the tectonic setting and mode of magma emplacement. In the northern Kitakami area of Northeast Japan, Early Cretaceous episodic magmatism occurred in a Jurassic accretionary complex, and formed the oxidised-type granitoids accompanied by submarine bimodal volcanism associated with kuroko mineralisation. Granitoids of fissure-filling type emplaced under extensional environments may be oxidised, irrespective of basement geology, because of insignificant crustal input.
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Golozubov, V. V. y A. I. Khanchuk. "HEILOGJIANG COMPLEX – FRAGMENT OF THE JURASSIC ACCRETIONARY WEDGE IN THE TECTONIC WINDOWS OF THE OVERLYING PLATE: FLAT-SLAB SUBDUCTION MODEL". Tikhookeanskaya Geologiya 40, n.º 4 (2021): 3–17. http://dx.doi.org/10.30911/0207-4028-2021-40-4-3-17.
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The Circum-Pacific Late Albian-Cenomanian orogenic belts (including the Sikhote-Alin-Western-Sakhalin belt) were formed as a result of the deformation of mainly epioceanic terranes – fragments of Jurassic-Early Cretaceous accretionary wedges with ophiolites and other fragments of oceanic crust, turbidite basins, and island-arc systems. To the west of the Sikhote-Alin - Northern-Sakhalin belt and orthogonally, there are structures of earlier consolidation, which include the Bureya-Jiamusi-Khanka fragment of the orogenic belt of the Late Cambrian-Early Ordovician consolidation of the Late Proterozoic - Cambrian complexes. Within this belt, four isolated outcrops of the Heilongjiang complex are mapped, combining metamorphites of the epidote-amphibolite and glaucophane-schist facies and representing a fragment of an accretionary wedge of the Jurassic age. It was assumed that these outcrops marked the suture, i.e., represented the remains of the closed Mudanjiang paleoocean, separating the original Jiamusi terrane (and the Bureya-Jiamusi-Khanka belt) located to the west of Central Asia structures. The proposed article provides data that the Heilongjiang complex does not mark a suture, but is an underground near-horizontal continuation of the marginal continental accretionary wedge of the Nadanhad - Bikin terrane (flat subduction model) brought to the surface at the site of the antiform bending. The unity of the compared parts of the accretionary wedge is emphasized by the close matrix age, the similarity of detritus zircon populations, and the similarity of the composition and age of allochthonous inclusions (limestone, chert, Late Paleozoic and Early Mesozoic basalt). An important common feature is that Late Paleozoic and Early Mesozoic basalts from allochthonous inclusions in both cases are represented by the N-MORB and OIB types, with no traces of suprasubduction volcanism in the matrix. The Heilongjiang complex forms, according to this interpretation, a tectonic window among the more ancient formations of the Jiamusi terrane. There is no need to assume the existence of the Mudanjiang Ocean to explain the formation of the Heilongjiang complex. The features of the structure of this complex and the conditions of its occurrence can be explained by the processes of flat subduction of the Pacific slab in the Jurassic and its deformation in the Early Cretaceous.
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Danyushevsky, L. V., T. J. Falloon, A. V. Sobolev, A. J. Crawford, M. Carroll y R. C. Price. "The H2O content of basalt glasses from Southwest Pacific back-arc basins". Earth and Planetary Science Letters 117, n.º 3-4 (junio de 1993): 347–62. http://dx.doi.org/10.1016/0012-821x(93)90089-r.
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Mudholkar, Abhay V. y Anil L. Paropkari. "Evolution of the basalts from three back-arc basins of southwest Pacific". Geo-Marine Letters 18, n.º 4 (diciembre de 1998): 305–14. http://dx.doi.org/10.1007/s003670050084.
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Mao, Qigui, Wenjiao Xiao, Brian F. Windley, Minjie Yu, Min Sun, Songjian Ao y Ji’en Zhang. "Early Permian subduction-related transtension in the Turpan Basin, East Tianshan (NW China): implications for accretionary tectonics of the southern Altaids". Geological Magazine 158, n.º 1 (14 de noviembre de 2019): 175–98. http://dx.doi.org/10.1017/s0016756819001006.
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AbstractThe interaction of the Palaeo-Pacific and Palaeo-Asian Oceans is an enigmatic issue as their temporal and spatial features are controversial. To address this issue, we present a systematic study of large volumes of early Permian volcanic rocks and intrusions developed in the East Tianshan. The represented samples of basaltic andesites and rhyolites yield zircon crystallization ages of 285.1 ± 5.9 Ma and 275.3 ± 1.8 Ma, respectively. The basalts have normal mid-ocean ridge basalt (N-MORB) and arc-related geochemical signatures with high TiO2 contents, negative Rb, Th, U, Nb and Ta anomalies and positive Eu anomalies. Basaltic andesites and andesites have arc-related geochemical characteristics with moderate TiO2 contents and relatively negative Nb, Ta and Ti anomalies, together with slightly negative to positive Eu anomalies. The rhyolites show an affinity with A2-type granite with high SiO2, K2O + Na2O, Fe/Mg, Ga, Zr, Nb, Y, HFSE, REE and Y/Nb levels (>1.2). These geochemical data suggest that the rocks formed in a supra-subduction zone. The presence of high ϵNd(t) values of +4.6 to +8.2 and low (87Sr/86Sr)i (0.70342–0.70591) values indicates that the volcanic rocks originated from a depleted mantle. We propose that oblique subduction with slabs breaking off gave rise to transtension and to the emplacement of large volumes of mantle-derived melts in the early Permian in the East Tianshan, serving as an important record of the subduction zone of the Palaeo-Pacific Ocean.
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Zhang, Y., S. Z. Li, Y. H. Suo, L. L. Guo, S. Yu, S. J. Zhao, I. D. Somerville et al. "Origin of transform faults in back-arc basins: examples from Western Pacific marginal seas". Geological Journal 51 (2 de junio de 2016): 490–512. http://dx.doi.org/10.1002/gj.2807.
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Dmitrenko, O. B. "Nannofossils in upper quaternary bottom sediments of back-arc basins in the southwestern Pacific". Oceanology 55, n.º 3 (mayo de 2015): 400–416. http://dx.doi.org/10.1134/s0001437015030030.
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Casey, Sean P. F., Andrew E. Dessler y Courtney Schumacher. "Five-Year Climatology of Midtroposphere Dry Air Layers in Warm Tropical Ocean Regions as Viewed by AIRS/Aqua". Journal of Applied Meteorology and Climatology 48, n.º 9 (1 de septiembre de 2009): 1831–42. http://dx.doi.org/10.1175/2009jamc2099.1.
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Abstract Many studies have commented on the presence of midtroposphere dry air layers in normally moist areas of the warm-pool region in the tropical western Pacific Ocean. In this study, 5 yr of relative humidity (RH) observations from the Atmospheric Infrared Sounder (AIRS) instrument aboard the Aqua satellite are analyzed to identify areas of anomalously dry air between 600 and 400 hPa over deep convective regions of the tropical oceans. A dry air layer is defined when midlevel RH is <20%, accounting for the lowest 10% of RH observations. Dry air layers appear to be more frequent over the Indian and Pacific Oceans than over the Atlantic Ocean. Large seasonal differences in the locations of dry air layers are apparent in each ocean basin. Large variations are also noted across the Pacific, suggesting limits on the applicability of case-study trends and observations of dry air layers to the Pacific as a whole. Back trajectories are then calculated for each observed parcel. The origin, or location of dehydration, is identified as the point along each trajectory at which the RH of the parcel is ≥100%. An analysis of the time between dehydration and dry air observation by AIRS suggests that dry air layers in June–August tend to last 1–2 days longer than those observed in other seasons. Although more dry air layers are observed to come from each hemisphere in its respective winter, most sources of dry air layers are subtropical and contribute anomalously dry air year-round. Other meteorological features are noted in the back trajectories, such as the eastward/westward wind transition from the subtropics to the tropics and the effects of the Indian monsoon on dry air distribution paths.
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GÜRER, Ö. F. y E. ALDANMAZ. "Origin of the Upper Cretaceous–Tertiary sedimentary basins within the Tauride–Anatolide platform in Turkey". Geological Magazine 139, n.º 2 (marzo de 2002): 191–97. http://dx.doi.org/10.1017/s0016756802006295.
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A number of sedimentary basins formed within the Tauride–Anatolide Platform of Anatolia during the Late Cretaceous–Tertiary period. Previous studies have proposed different tectonic and evolutionary models for each basin. Geological characteristics of the basins, however, suggest that all these basins are of the same origin and that they followed a similar evolutionary model to one another. Basin development within the Tauride–Anatolide Platform took place in a post-collisional environment following the northward subduction of the northern Neotethys ocean beneath the Pontides. The closure of the northern Neotethys ocean ended with collision of the Tauride–Anatolide Platform with the Pontide volcanic arc and resulted in large bodies of oceanic remnants thrust over the Tauride–Anatolide Platform as ophiolite nappes. Formation of the sedimentary basins followed the emplacement of the ophiolite nappes as they formed as piggy-back basins on top of the underlying thrust ophiolite basement.
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Lisitzin, A. P., V. N. Lukashin, V. V. Gordeev, T. F. McConachy, S. D. Scott y V. P. Shevchenko. "Hydrological and geochemical anomalies associated with hydrothermal activity in SW Pacific marginal and back-arc basins". Marine Geology 142, n.º 1-4 (octubre de 1997): 7–45. http://dx.doi.org/10.1016/s0025-3227(97)00039-x.
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DESBRUYERES, D., A. ALAYSEDANET, S. OHTA y THESCIENTIFICPARTIESOFBIOLAUA. "Deep-sea hydrothermal communities in Southwestern Pacific back-arc basins (the North Fiji and Lau Basins): Composition, microdistribution and food web". Marine Geology 116, n.º 1-2 (enero de 1994): 227–42. http://dx.doi.org/10.1016/0025-3227(94)90178-3.
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Keith, Manuel, Karsten M. Haase, Reiner Klemd, Ulrich Schwarz-Schampera y Henrike Franke. "Systematic variations in magmatic sulphide chemistry from mid-ocean ridges, back-arc basins and island arcs". Chemical Geology 451 (febrero de 2017): 67–77. http://dx.doi.org/10.1016/j.chemgeo.2016.12.028.
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Jolivet, Laurent, Claudio Faccenna, Nicola D’Agostino, Marc Fournier y Dan Worrall. "The kinematics of back-arc basins, examples from the Tyrrhenian, Aegean and Japan Seas". Geological Society, London, Special Publications 164, n.º 1 (1999): 21–53. http://dx.doi.org/10.1144/gsl.sp.1999.164.01.04.
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Martinez, Fernando y Brian Taylor. "Controls on back-arc crustal accretion: insights from the Lau, Manus and Mariana basins". Geological Society, London, Special Publications 219, n.º 1 (2003): 19–54. http://dx.doi.org/10.1144/gsl.sp.2003.219.01.02.
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Gordienko, I. V., O. R. Minina, L. I. Vetluzhskikh, A. Ya Medvedev y D. Odgerel. "Hentei-Dauria fold system of the Mongolia-Okhotsk belt: magmatism, sedimentogenesis, and geodynamics". Geodynamics & Tectonophysics 9, n.º 3 (9 de octubre de 2018): 1063–97. http://dx.doi.org/10.5800/gt-2018-9-3-0384.
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The geostructural, petrological, geochemical, geochronological and biostratigraphic studies were conducted in the Hentei-Dauria fold system of the Mongolia-Okhotsk orogenic belt. This Paleozoic system is composed mainly of three heterochronous rock associations related to the onset and development of oceanic basins and active margins in the conjugation zone of the Siberian continent and the Mongolia-Okhotsk ocean. This region developed in three stages: (1) Late Caledonian (Ordovician – Early Silurian), (2) Early Hercynian (Late Silurian – Devonian), and (3) Late Hercynian (Carboniferous–Permian). In the Late Caledonian, oceanic seafloor spreading was initiated, deep-sea siliceous deposits were formed, basaltic and andesitic pillow lavas were erupted, and layered and cumulative gabbros, gabbro-dolerite dykes and subduction zones with island-arc magmatism were formed. After a short quiescence period, new zones of spreading and subduction occurred at the active margins of the Mongolia-Okhotsk ocean in the Early Hercynian. In the Late Hercynian, large back-arc sedimentary basins, accretionary prisms and connecting intraplate magmatic complexes were formed in all structures of the Hentei-Dauria fold system. As a result of our studies, we propose a comprehensive model showing the geodynamic development of the Hentei-Dauria fold system that occurred in the area of the Mongolia-Okhotsk Ocean and its margins.
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KASAHARA, Junzo, Shozaburo NAGUMO, Sadayuki KORESAWA, Toru OUCHI y Hajimu KINOSHITA. "SEISMIC ACTIVITY AND CRUSTAL STRUCTURE IN BACK-ARC BASINS NEAR JAPANESE ISLANDS DEDUCED FROM OCEAN BOTTOM SEISMOLOGICAL OBSERVATIONS". Journal of Physics of the Earth 36, Proceeding1 (1988): S31—S38. http://dx.doi.org/10.4294/jpe1952.36.proceeding1_s31.
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Makrygina, V. A., V. G. Belichenko y L. Z. Reznitsky. "Types of paleoisland arcs and back-arc basins in the northeast of the Paleoasian Ocean (from geochemical data)". Russian Geology and Geophysics 48, n.º 1 (enero de 2007): 107–19. http://dx.doi.org/10.1016/j.rgg.2006.12.010.
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McAllister, Sean M., Richard E. Davis, Joyce M. McBeth, Bradley M. Tebo, David Emerson y Craig L. Moyer. "Biodiversity and Emerging Biogeography of the Neutrophilic Iron-Oxidizing Zetaproteobacteria". Applied and Environmental Microbiology 77, n.º 15 (10 de junio de 2011): 5445–57. http://dx.doi.org/10.1128/aem.00533-11.
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ABSTRACTMembers of the neutrophilic iron-oxidizing candidate classZetaproteobacteriahave predominantly been found at sites of microbially mediated iron oxidation in marine environments around the Pacific Ocean. Eighty-four full-length (>1,400-bp) and 48 partial-lengthZetaproteobacteriasmall-subunit (SSU) rRNA gene sequences from five novel clone libraries, one novelZetaproteobacteriaisolate, and the GenBank database were analyzed to assess the biodiversity of this burgeoning class of theProteobacteriaand to investigate its biogeography between three major sampling regions in the Pacific Ocean: Loihi Seamount, the Southern Mariana Trough, and the Tonga Arc. Sequences were grouped into operational taxonomic units (OTUs) on the basis of a 97% minimum similarity. Of the 28 OTUs detected, 13 were found to be endemic to one of the three main sampling regions and 2 were ubiquitous throughout the Pacific Ocean. Additionally, two deeply rooted OTUs that potentially dominate communities of iron oxidizers originating in the deep subsurface were identified. Spatial autocorrelation analysis and analysis of molecular variance (AMOVA) showed that geographic distance played a significant role in the distribution ofZetaproteobacteriabiodiversity, whereas environmental parameters, such as temperature, pH, or total Fe concentration, did not have a significant effect. These results, detected using the coarse resolution of the SSU rRNA gene, indicate that theZetaproteobacteriahave a strong biogeographic signal.
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Durand, Pascale, Afeda Benyagoub y Daniel Prieur. "Numerical taxonomy of heterotrophic sulfur-oxidizing bacteria isolated from southwestern Pacific hydrothermal vents". Canadian Journal of Microbiology 40, n.º 8 (1 de agosto de 1994): 690–97. http://dx.doi.org/10.1139/m94-110.
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Sulfur-oxidizing bacteria (n = 161) were enriched and isolated from samples of vent water, invertebrates, and chimney rocks collected at two deep-sea hydrothermal vents (2000 m) in back-arc basins from the southwestern Pacific: the North Fiji Basin and the Lau Basin. Several types of heterotrophic sulfur-oxidizing bacteria were repeatedly isolated. They oxidized thiosulfate either to sulfate (acid producing) or to polythionate (base producing). In most of the acid-producing cultures, thiosulfate was transitorily oxidized to polythionate. All of the bacteria were Gram negative, 37% were fermentative, and 88% were denitrifiers or nitrate reducers. Numerical taxonomy and analysis of the G+C content showed that they belong to several genera including Pseudomonas, Acinetobacter, and Vibrio.Key words: hydrothermal vent, culturable thiosulfate-oxidizing bacteria, numerical taxonomy.
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Benedict, Imme, Chiel C. van Heerwaarden, Ruud J. van der Ent, Albrecht H. Weerts y Wilco Hazeleger. "Decline in Terrestrial Moisture Sources of the Mississippi River Basin in a Future Climate". Journal of Hydrometeorology 21, n.º 2 (febrero de 2020): 299–316. http://dx.doi.org/10.1175/jhm-d-19-0094.1.
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AbstractAssessment of the impact of climate change on water resources over land requires knowledge on the origin of the precipitation and changes therein toward the future. We determine the origin of precipitation over the Mississippi River basin (MRB) using high-resolution (~25 km) climate model simulations for present and future climate (RCP4.5). Moisture resulting in precipitation over the MRB is tracked back in time using Eulerian offline moisture tracking, in order to find out from where this water originally evaporated (i.e., the moisture sources). We find that the most important continental moisture sources are the MRB itself and the area southwest of the basin. The two most relevant oceanic sources are the Gulf of Mexico/Caribbean and the Pacific. The distribution of sources varies per season, with more recycling of moisture within the basin during summer and more transport of moisture from the ocean toward the basin in winter. In future winters, we find an increase in moisture source from the oceans (related to higher sea surface temperatures), resulting in more precipitation over the MRB. In future summers, we find an approximately 5% decrease in moisture source from the basin itself, while the decrease in precipitation is smaller (i.e., lower recycling ratios). The results here are based on one climate model, and we do not study low-frequency climate variability. We conclude that Mississippi’s moisture sources will become less local in a future climate, with more water originating from the oceans.
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Kazmin, V. G. y N. F. Tikhonova. "Evolution of Early Mesozoic back-arc basins in the Black Sea-Caucasus segment of a Tethyan active margin". Geological Society, London, Special Publications 260, n.º 1 (2006): 179–200. http://dx.doi.org/10.1144/gsl.sp.2006.260.01.08.
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Acosta-Góngora, P., S. J. Pehrsson, H. Sandeman, E. Martel y T. Peterson. "The Ferguson Lake deposit: an example of Ni–Cu–Co–PGE mineralization emplaced in a back-arc basin setting?" Canadian Journal of Earth Sciences 55, n.º 8 (agosto de 2018): 958–79. http://dx.doi.org/10.1139/cjes-2017-0185.
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The world’s largest Ni–Cu–Platinum group element (PGE) deposits are dominantly hosted by ultramafic rocks within continental extensional settings (e.g., Raglan, Voisey’s Bay), resulting in a focus on exploration in similar geodynamic settings. Consequently, the economic potential of other extensional tectonic environments, such as ocean ridges and back-arc basins, may be underestimated. In the northeastern portion of the ca. 2.7 Ga Yathkyed greenstone belt of the Chesterfield block (western Churchill Province, Canada), the Ni–Cu–Co–PGE Ferguson Lake deposit is hosted by >2.6 Ga hornblenditic to gabbroic rocks of the Ferguson Lake Igneous Complex (FLIC), which is metamorphosed up to amphibolitic facies. The FLIC has a basaltic composition (Mg# = 31–72), flat to slightly negatively sloped normalized trace element patterns (La/YbPM = 0.7–3.5), and negative Zr, Ti, and Nb anomalies. The FLIC rocks are geochemically similar to the 2.7 Ga back-arc basin tholeiitic basalts from the adjacent Yathkyed and MacQuoid greenstone belts (Mg# = 30–67; La/YbPM = 0.3–3.0), but the Ferguson Lake intrusions appear to be more crustally contaminated. We interpret the FLIC to have formed in an equivalent back-arc basin setting. This geodynamic setting is rare for the formation of Ni–Cu–PGE occurrences, and only few examples of this tectonic environment (or variations of it, e.g., rifted back-arc) are found in other Proterozoic and Archean sequences (e.g., Lorraine deposit, Quebec). We suggest that back-arc basin-derived mafic rocks within the Yathkyed and other Neoarchean greenstone belts of the Chesterfield block (MacQuoid and Angikuni) could represent important targets for future mineral exploration.
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Bezverkhny, V. L. y E. B. Osipova. "A possible mechanism of inversion of the vertical lithosphere movements in the back-arc basins of the West Pacific region". Russian Journal of Pacific Geology 3, n.º 2 (abril de 2009): 128–36. http://dx.doi.org/10.1134/s1819714009020031.
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Denis, Françoise, Didier Jollivet y Dario Moraga. "Genetic separation of two allopatric populations of hydrothermal snails Alviniconcha spp. (Gastropoda) from two South Western Pacific back-arc basins". Biochemical Systematics and Ecology 21, n.º 4 (junio de 1993): 431–40. http://dx.doi.org/10.1016/0305-1978(93)90101-v.
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