Littérature scientifique sur le sujet « Structural Northern Territory Arunta Block »

The Neoproterozoic to Late Paleozoic-aged Amadeus Basin is a large (~170 000 km2) east–west-trending basin, bounded to the south by the Musgrave Province and to the north by the Arunta Block of the Northern Territory. Commercial oil and gas production is established in the northern part of the basin but the southern part is still a frontier exploration area. Vintage and new seismic reflection data have been used with well data along the south-eastern Amadeus Basin to construct a new structural and depositional model. Three major phases of deformation controlling deposition have been identified. The first phase is characterised by a SW–NE trending structural fabric and is thought to be older than the deposition of the first sediments identified above basement (Heavitree and Bitter Springs formations). The second phase corresponds to the Petermann Orogeny (580–540 Ma) and trends in a NW–SE orientation. The third phase is the Alice Springs Orogeny (450–300 Ma) and is oriented W–E to WNW–ESE in this part of the basin. This tectono-stratigraphic model involving three distinct phases of deformation potentially explains several critical observations: the lack of Heavitree reservoir at Mt Kitty-1, limited salt movements before the Petermann Orogeny (~300 Ma after its deposition) and salt-involved structures that can be either capped by the Petermann Unconformity and overlying Cambrian to Devonian sediments, or can reach the present day surface. Finally, this model, along with availability of good quality seismic data, opens new perspectives for the hydrocarbon exploration of the Amadeus Basin. Each of the tectonic phases impacts the primary petroleum system and underpins play-based exploration.

AbstractNearly boron-free kornerupine is locally abundant in pods or lenses of coarse-grained, non-foliated, Mg- and Al-rich rocks that occur at high metamorphic grades in early Proterozoic metapelitic rocks from the Reynolds Range, Northern Territory, Australia. This is the third reported occurrence of boron-free kornerupine worldwide. The samples consist almost entirely of coarse-grained kornerupine and its breakdown products sapphirine, cordierite, and gedrite or orthopyroxene. The kornerupine contains only 0.45 wt.% B2O3, corresponding to 0.098 B atoms per 22 (O, OH), and closely approximates 11:10:11 in terms of molar ratios of (MgO + FeOtotal):Al2O3:SiO2, with XMg = Mg/(Mg + Fetotal) = 0.874. The unusual textures and bulk compositions of the rocks in the pods are interpreted to have resulted from metasomatism and high-grade metamorphism (750 to 800° and ∼ 4.5 kbar) of precursors that may have included sedimentary Mg-rich clays. Rocks containing boron-poor, and relatively boronrich kornerupine (2.18 wt.% B2O3; XMg = 0.892) are separated in outcrop by as little as 10 m of the foliated cordierite-quartzite country rock and other rock types, suggesting that the compositions or amounts of the metasomatic fluids varied on a local scale.

The Onshore Energy Security Program—funded by the Australian Government and conducted by Geoscience Australia—has acquired deep seismic reflection data in conjunction with state and territory geological surveys, across several frontier sedimentary basins to stimulate petroleum exploration in onshore Australia. Here, we present data from two seismic lines collected in SA and NT. Seismic line 08GA-OM1 crossed the Arckaringa and Officer basins in SA and the southern-most Amadeus Basin in NT. Seismic line 09GA-GA1 crossed the northeastern part of the Amadeus Basin and the complete width of the southern Georgina Basin in NT. Structural and sequence stratigraphic interpretations of the seismic lines will be presented here, followed by an assessment of the petroleum potential of the basins. Seismic line 08GA-OM1 also crosses the Neoproterozoic to Devonian eastern Officer Basin. The basin is structurally complex in this area, being dominated by south-directed thrust faults and fault-related folds—providing potential for underthrust petroleum plays. The northern margin of the basin is overthrust to the south by the Mesoproterozoic Musgrave Province. To the north, the Moorilyanna Trough of the Officer Basin is a major depocentre of up to 7,000 m deep. Both seismic lines cross parts of the eastern Amadeus Basin. Seismic line 08GA-OM1 shows that the southern margin of the basin is overthrust to the north by the Musgrave Province with the main movement during the Petermann Orogeny. In the northeast, seismic line 09GA-GA1 crosses two parts of the basin separated by the Paleoproteroozic to Mesoproterozoic Casey Inlier (part of the Arunta Region). The northern margin of the basin is imaged seismically as a southward-verging, thinned-skinned thrust belt, showing considerable structural thickening of the stratigraphic succession. Seismic line 09GA-GA1 was positioned to cross that part of the southern Georgina Basin that was considered previously to be in the oil window. Here, the basin has a complex southern margin, with Neoproterozoic stratigraphy being thrust interleaved with basement rocks of the Arunta Region. The main part of the basin, containing a Neoproterozoic to Devonian succession, is asymmetric, thinning to the north where it overlies the Paleoproterozoic Davenport Province. The well, Phillip–2, drilled adjacent to the seismic line, intersected basement at a depth of 1,489 m, and has been used to map the stratigraphic sequences across the basin.

Research subject. A series of research studies was conducted in the Alai Range area, at the junction of the folded Tien Shan and Pamir provinces with the purpose of investigating the morphological structure of alpine deformations in the Paleozoic basement and Mesozoic–Cenozoic sediment cover.Materials and Methods. Structural and geological observations were carried out in the Alai and Kichi-Karakol inter-mountain depressions and their mountainous surroundings. These investigations included an analysis of the morphology and orientation of the deformation structures of the sedimentary cover and structural inconsistencies based on detailed geological mapping; measurements of the orientations of tectonic slickenlines and slickensides in the zones of active faults; processing the entire complex of data in terms of kinematic strain indicators using proven methods and calculation programs in order to determine the main parameters of the stress-strain state of the upper crustal rock complexes.Results. The age intervals and kinematic conditions of the main phases of structural transformation of the Southern Tien Shan at the Alpine stage of tectogenesis were determined based new structural and geological data, as well as materials published in previous works. It was demonstrated that, in the territory of Alai, the most significant deformations and activation of the Paleozoic basement faults occurred at the Neogene-Quarter boundary. Conclusions. At the present stage, the area under study constitutes a relatively stable block, which does not experience significant deformations associated with the encroachment of the upper crustal rock complexes of the Northern Pamir from the south.

Based on the electronic atlas “Baikal Region: Society and Nature”, the problem of landscape-cartographic support for studying the transformations of vast territories is being solved. The transformation of geosystems is understood as changes in the natural environment due to spontaneous development or anthropogenic interference. In this context, potential and actual transformations are distinguished. The research of potential transformations is associated with a geographic forecast of possible changes in the state of the environment due to external impact, and current transformations include an assessment of its current ecological state. The area under investigation includes the territory of the Baikal basin, and the northern regions of Mongolia. This aspect is realized through the integration of a multitude of geographical data on the structure of natural systems, their sustainability and trends of anthropogenic transformations into a single target cartographic information system (CIS). The main requirement for the content of the target block of maps is the reliability of the results of a comprehensive research and their evidentiality if used to make management decisions to optimize the environment. A logical and methodological coherence of small-scale target mapping of the natural environment of a vast territory has been developed. The analysis of natural structures was carried out and a basic inventory map of geosystems of scale (M 1:5,000,000) was created. We developed a set of geosystem characteristics and carried out an environmental interpretation of information and integrated environmental mapping, aside from that implemented geoecological zoning of the territory. Based on the information synthesis of the obtained data and knowledge about the modern landscape structure of the region, the methods of polysystem analysis, we revealed the nature of sustainability, functions, value characteristics of geosystems and the patterns of their anthropogenic transformations. The presence of a single set of maps will provide a study of questions about potential and relevant transformations of geosystems. The small-scale maps of the Baikal region, compiled in a certain sequence on the basis of a single structural-hierarchical specialized classification, reflect a complex of environmental conditions that are important for making constructive-geographical, design, managerial, and environmental decisions.

Актуальность рассматриваемой темы в том, что орогенные пояса материковой части Камчатского края насыщены полезными ископаемыми, приуроченных к поясам, образованным последовательным приростом окраин континента от древних с северо-запада к юго-востоку. Такими поясами с месторождениями Ag, Au, Sn, Hg, S являются Северо-Западно-Корякский олигоценовый и Южно-Корякский миоценовый, образованные на северной и южной границе Центрально-Корякской окраины позднемелового континента. Они сформированы в олигоцене и миоцене изолированными вулканогенами локальных андезитовых полей, прорванных гранитоидами тектонической активизации. С ними связаны рудные площади, локализация которых позволит обеспечить прирост запасов разрабатываемых россыпей платиноидов. Цель работы заключается в установлении тектонических закономерностей образования вулканогенов, связанных с ними рудных районов и получения новых данных по их прогнозу. В Северо-Западном поясе оформилась металлогеническая зона с Уннэйваямским, Гайчаваямским и Пальматкинским районами, сопряжёнными с одноименными вулканогенами, в Южно-Камчатском с Ветроваямским вулканогеном. Методология и методы исследования. Методология заключена в глыбово-клавишной структуре литосферы и её земной коры на активных окраинах континента. Методика основана на установлении системной связи структурных элементов геолого-геофизической системы тектоника-вулканогены . Результаты работ и их анализ. Предложена схема закономерностей размещения известных и прогнозируемых рудных районов, узлов юго-запада Корякского нагорья. Они обусловлены глыбово-клавишной тектоникой и локализованы в звеньях серии продольных субпараллельных разновозрастных региональных структур СВ простирания, последовательно наращивающих континент к юго-востоку. Звенья являются дискретными и определяют размеры рудных районов. Рассмотрены выделяемые звенья Северо-Западно-Корякского олигоценового и Южно-Корякского миоценового поясов. В первом СЗ поперечными межглыбовыми разломами литосферы образованы вулканогены гнездового типа. Они возникли на пересечении фундамента позднего мела и южной окраины сопредельной Пенжинской СФЗ поперечными межглыбовыми разломами. В пересечениях образуется литосферный столб вещества гранитоидной активизации верхней мантии и позднемелового осадочного разреза фундамента. Делается вывод, что в Южно-Корякском поясе вулканоген является линейным, образованным заключением линейного СВ Ветроваямского выступа фундамента и чехла между двумя поперечными межглыбовыми разломами. В нём рудоносными вторичными кварцитами создан Ильпинский рудный район с крупными месторождениями самородной серы с Ag, Au, Hg, S. Орогенный вулканизм на активных окраинах континентов сопряжён с основными элементами тектоники и магматизма, создавшими условия образования минерагенических таксонов. На примерах орогенных поясов олигоцена и миоцена очевидна роль геотектонических и металлогенических аспектов авторской методологии глыбово-клавишной структуры литосферы активных окраин. Она эффективна в прогнозе рудных площадей и их оценке последующими геологоразведочными работами. The relevance of the work is that the orogenic belts of the mainland of the Kamchatka Territory are saturated with minerals confined to the belts formed by the successive growth of the continental margins from the ancient ones from the north-west to the south-east. Such belts with deposits of Ag, Au, Sn, Hg, S are the Northwest Koryak Oligocene and South Koryak Miocene, formed on the northern and southern borders of the Central Koryak margin of the Late Cretaceous continent. They are formed in the Oligocene and Miocene by isolated volcanogens of local andesitic fields, broken by granitoids of tectonic activation. Ore areas are associated with them, the localization of which will ensure an increase in the reserves of developed placer deposits. The purpose of the work is to establish tectonic patterns of formation of volcanogens, associated ore regions and obtain new data on their forecast. In the North-Western zone, a metallogenic zone took shape with the Unneivayamsky, Gaichavayamsky and Palmatkinsky regions, associated with the same named volcanogenes, in the South Kamchatka - with the Vetrovayamsky volcanogen. Methodology and research methods. The methodology lies in the block-key structure of the lithosphere and its earths crust on the active margins of the continent. The methodology is based on establishing a systemic connection between the structural elements of the geological and geophysical system tectonics-volcanogens. The results of the work and their analysis. A scheme of patterns of distribution of known and predicted ore regions, nodes of the south-west of the Koryak upland is proposed. They are caused by block-key tectonics and are localized in the links of a series of longitudinal subparallel regionally different age structures of NE strike, successively expanding the continent to the southeast. The links are discrete and determine the size of the ore regions. The distinguished links of the Northwest Koryak Oligocene and South Koryak Miocene belts are considered. In the first northwestern region, nesting volcanogens are formed by transverse interblock faults of the lithosphere. They arose at the intersection of the Late Cretaceous foundation and the southern edge of the adjacent Penzhinsk structural-facial zone with transverse interblock faults. At the intersections, a lithospheric column of granitoid activation matter of the upper mantle and the Late Cretaceous sedimentary section of the basement is formed. It is concluded that the volcanogen in the South Koryak belt, has a linear nature, formed by the conclusion of a linear NE of Vetrovayamsk ledge of the basement and cover between two transverse interblock faults. There ore-bearing secondary quartzites created the Ilpinsk ore region with large deposits of native sulfur with Ag, Au, Hg, S. The orogenic volcanism on the active margins of the continents is associated with the basic elements of tectonics and magmatism, which created the conditions for the formation of minerogenic taxons. The role of geotectonic and metallogenic aspects of the authors methodology of the block-key structure of the active lithosphere margins is evident on the examples of the orogenic Oligocene and Miocene belts. It is effective in forecasting ore areas and evaluating them with subsequent exploration works

Typescript (Photocopy)<br>Copies of 4 published papers co-authored by author, and 7 maps, in back cover pocket.<br>Bibliography: leaves 203-218.<br>[232] leaves : ill., maps (some col.) ; 30 cm.<br>Title page, contents and abstract only. The complete thesis in print form is available from the University Library.<br>Thesis (Ph.D.)--University of Adelaide, Dept. of Geology and Geophysics, 1989

This item is only available electronically.<br>The Arunta Inlier preserves a complex structural history, subject to a series of igneous, metamorphic and deformational events from the Paleoproterozoic to the mid-Paleozoic. U-Pb detrital zircon ages from Paleoproterozoic and Neoproterozoic sediments at Ormiston Gorge coincide with the timing of various tectonic phases in the Arunta Inlier. First order interpretations suggest that the Northern Arunta Inlier was the source of the oldest zircons recorded at ~1820 Ma, coinciding with the timing of the Stafford Event. The Strangways Orogeny at ~1770 Ma and 1730 Ma is the earliest deformation preserved in the Central Arunta Inlier and is probably the source of zircons accumulated in these sediments. Zircons post-dating the Strangways Orogeny are likely sourced from the Southern Arunta Inlier, coinciding with the Argilke Tectonic Event at ~1680 Ma, the Chewings Orogeny at ~1600 Ma, the Anmatjira Uplift Phase at 1500-1400 Ma and the emplacement of the Teapot Granite Complex at ~1140 Ma. The Neoproterozoic Heavitree Range Quartzite sediments represent initial deposition in the Amadeus Basin, which forms the remnant of a once much larger intracratonic basin in central Australia known as the Centralian Superbasin. The Arunta Inlier was exhumed from beneath the Centralian Superbasin during the Devonian-Carboniferous Alice Springs Orogeny, forming a series of subbasins including the Amadeus, Ngalia and Georgina Basins. North-south crustal compression during this Orogeny reactivated a series of steep north-dipping Mesoproterozoic fault structures including the Redbank shear zone and the Ormiston thrust zone. The northern Amadeus Basin is characterised by coupled basement and cover deformation, producing a series of basement-rooted south-propagating thrusts, which penetrate the basal Heavitree Range Quartzite. Structural cross-sections constructed across the Ormiston region propose a series of splay thrusts within the Ormiston thrust zone, with the basement and Heavitree Quartzite heavily deformed. The conformably overlying Bittersprings Formation comprises salts and evaporates, interpreted as a detachment layer. 40Ar/39Ar muscovite dating of mylonitic shear zones at Ormiston Gorge have constrained ‘peak deformation’ conditions in the region to a minimum age of 350 ± 3 Ma. Mineral assemblages formed in the surrounding areas reflect greenschist to lower amphibolite facies metamorphism, with temperatures reaching at least 350°C.<br>Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, YEAR