Journal articles on the topic 'Leptynite'

Arrested-type charnockite formation occurs in an assemblage of high-grade gneisses at several localities of the Chilka Lake area that belongs to the Proterozoic Eastern Ghats Belt of India. The isolated ellipsoidal domains are found exclusively in leucogranite (leptynite) bands that intruded lit-par- lit interbanded granulite-grade supracrustal and intermediate igneous rocks (khondalite–enderbite). Macrostructures and microfabrics document a multiple deformation of the rock assemblage under high-grade conditions. The intrusion of the leucogranitic melts separates a first episode of deformation, D1, from a younger progressive deformation, D2–D4. A transpressive regime and inhomogeneous deformation is indicated for D2–D4 by the associated structures and fabrics. But quartz c-axis patterns show that pure shear prevailed during the closing stages of deformation. The spatial distribution and orientation of the ellipsoidal charnockite domains within the host leptynite and the orientation pattern of orthopyroxene c-axes inside the domains provide evidence for a synkinematic in situ formation of the domains during D3, through partial breakdown of the leptynite assemblage (Bt+Grt+Qtz+Fl1[rlhar ]Opx+Fsp+Ilm+Fl2/L). Local fluid migration along steep foliation planes associated with large-scale D3 folds triggered the reaction. Orthopyroxene blastesis was confined to the centre of the domains, and an envelope formed in which the residing fluid caused secondary intergranular formation of chlorite, ore and carbonate, imparting the domains' typical greenish-brown charnockite colour. The shape of the envelope, which varies from prolate in limbs to oblate in hinges of D3 folds, is responsive to the local stress field. Comparison of chemical rock compositions supports the in situ formation of charnockite in leptynite. Subtle compositional differences are controlled by the changing mineralogy. Compared to the host leptynite, the charnockite domains are enriched in K2O, Ba, Rb and Sr, but depleted in FeO*, MnO, Y and Zr. The data obtained in this study provide conclusive evidence that the ellipsoidal charnockite domains do not represent remnants of stretched enderbite layers as proposed by Bhattacharya, Sen & Acharyya, but formed in situ in the leptynite as a result of localized synkinematic fluid migration late in the deformation history.

AbstractThe Diguva Sonaba area (Vishakhapatnam district, Andhra Pradesh, South India) represents part of the granulite-facies terrain of the Eastern Ghats Mobile Belt. The Precambrian metamorphic rocks of the area predominantly consist of mafic granulite (±garnet), khondalite, leptynite (±garnet, biotite), charnockite, enderbite, calc-granulite, migmatic gneisses and sapphirine–spinel-bearing granulite. The latter rock type occurs as lenticular bodies in khondalite, leptynite and calc-granulite. Textural relations, such as corroded inclusions of biotite within garnet and orthopyroxene, resorbed hornblende within pyroxenes, and coarse-grained laths of sillimanite, presumably pseudomorphs after kyanite, provide evidence of either an earlier episode of upper-amphibolite-facies metamorphism or they represent relics of the prograde path that led to granulite-facies metamorphism. In the sapphirine–spinel-bearing granulite, osumilite was stable in addition to sapphirine, spinel and quartz during the thermal peak of granulite-facies metamorphism but the assemblage was later replaced by Crd–Opx–Qtz–Kfs-symplectite and a variety of reaction coronas during retrograde overprint. Variable amounts of biotite or biotite+quartz symplectite replaced orthopyroxene, cordierite and Opx–Crd–Kfs–Qtz-symplectite at an even later retrograde stage. Peak metamorphic conditions of c. 1000°C and c. 12 kbar were computed by isopleths of XMg in garnet and XAl in orthopyroxene. The sequence of reactions as deduced from the corona and symplectite assemblages, together with petrogenetic grid and pseudosection modelling, records a clockwise P–T evolution. The P–T path is characteristically T-convex suggesting an isothermal decompression path and reflects rapid uplift followed by cooling of a tectonically thickened crust.

AbstractDark patches of charnockitic rocks characterized by orthopyroxene occur within garnetiferous granite gneisses (leptynites) in a granulite-migmatite suite around the Chilka Lake, Orissa, within the Eastern Ghats belt in the Indian Precambrian. Analysis of structures of different scales observed in this terrain establishes the presence of three phases of deformation. S1 is pervasive in the metapelitic granulites (mainlykhondalite), while in the migmatite complex composed of leptynites, charnockites and quartzofeldspathic veins, S1 is present exclusively within the charnockite lenses and bands, and shows different stages of obliteration in the associated leptynites. Thus, the charnockite patches must be earlier than the surrounding migmatitic rocks. The charnockite patches and the surrounding leptynitic gneisses are chemically quite different and the two rock types are not related by any prograde or retrograde transformation. The shapes and disposition of charnockite patches in the mixed exposures are found to be largely controlled by the third phase of folding and locally associated shearing. The kinematics of this late deformation are not favourable for fluid ingress from deeper levels.

Leptynia specimens were analyzed by karyotype analysis, mitochondrial gene sequencing and SEM of bodies and eggs. Here we describe a new species, Leptynia annaepaulae, and three subspecies of L. attenuata Pantel (L. attenuata attenuata, L. attenuata iberica, L. attenuata algarvica). The phylogeny of the genus Leptynia is congruent with a karyotype trend toward a reduction of chromosome number and the shift from the shared XX/X0 sex chromosome formula to the unusual XX/XY one. Chromosome repatterning appears to occur ahead of genetic differentiation, following a chromosome model of cladogenesis. Chromosome and genetic differentiation, in turn, appears to precede morphological distinction, thus realizing a condition of incipient species for most of the Leptynia taxa. Actually, morphological analyses revealed that, only rarely clear cut differences exist among and between taxa, while, more often, just trends in the differentiating traits occur, since the investigated characters generally suffer from some overlapping: In this study, only the 10th:9th ratio value and the subanal vomer appear to be diagnostic for L. annaepaulae against all other Leptynia taxa. As a consequence, the subanal vomer as well as cercus tooth features with egg chorion traits are not sharply diagnostic for the remaining co-generic taxa; however, comparisons are quite helpful in reducing uncertainties. A likely phylogeographic scenario for the genus supports that Leptynia ancestors spread from Northern Africa into Southern Spain where an ancestral taxon originated L. annaepaulae (2n = 40/39, XX/X0, with 2 large dibrachial pairs). Later on, a northbound colonization, should have originated L. caprai (2n = 40/39, XX/X0, all acrocentrics), from which L. montana (2n = 38, XX/X0) and L. attenuata (2n = 36, XY/XX) originated; supporting instances of chromosome repatterning have been actually observed. In this connection we like to stress that, particularly in stick insects, androgenesis has been a preferential pathway to quickly make homozygous those odd chromosome rearrangements likely responsible for low fitness in the heterozygotes.

The Late Paleozoic–Early Mesozoic tectonic evolution of the Changchun-Yanji suture (CYS) was mainly associated with the Paleo-Asian and Mudanjiang tectonic regimes. However, the spatial and temporal overprinting and variations of these two regimes remains are still dispute. In order to evaluate this issue, in this contribution, we present new zircon U-Pb ages and a whole-rock geochemical and zircon Hf isotopic dataset on a suite of metamorphic rocks, including gneisses, actinolite schist, leptynites, and biotite schists, from tectonic mélanges in northern Liaoning and central Jilin provinces, NE China. Based on zircon LA-ICP-MS U-Pb dating results, protoliths show wide ranges of aging spectrum, including Paleoproterozoic (2441 Ma), Early Permian (281 Ma), Late Permian (254 Ma), and Late Triassic (230 Ma). The Permian protoliths of leptynites from the Hulan Tectonic Mélange (HLTM) and gneisses from the Kaiyuan Tectonic Mélange (KYTM) exhibit arc-related geochemical signatures, implying that the Paleo-Asian Ocean (PAO) did not close prior to the Late Permian. The Late Triassic protoliths of gneisses from the KYTM, in combination with previously reported coeval igneous rocks along the CYS, comprises a typical bimodal igneous suite in an E–W-trending belt, suggesting a post-orogenic extensional environment. Consequently, we infer that the final closure of the PAO took place during the Early–Middle Triassic. The Early Permian protoliths of biotite schists from the HLTM are alkali basaltic rocks and contain multiple older inherited zircons, which, in conjunction with the geochemical features of the rocks, indicate that they were generated in a continental rift related to the initial opening of the Mudanjiang Ocean (MO). Data from this contribution and previous studies lead us to conclude that the MO probably opened during the Middle Triassic, due to the north–south trending compression caused by the final closure of the PAO.

Abstract U-Pb zircon and Rb-Sr geochronological, and Sm-Nd isotopic studies have been carried out on the so-called leptyno-amphibolitic complex of the central part of the Maures Massif. The emplacement of the protolith of the felsic end-member (« leptynites ») has been dated at 548 Ma, an age much older than those (lower Ordovician) previously obtained on other leptyno-amphibolitic complexes. Rb-Sr data obtained on whole rocks and on mineral separates give an age of 348 Ma for the amphibolite-facies metamorphism. Nd isotopes indicate that the amphibolites display clear-cut mantle-derived signatures, whereas a significant crustal contribution is recorded in the three analyzed felsic facies. One of these acidic terms can be interpreted in terms of a simple mixing between two components, respectively similar to the amphibolites and to the two other felsic samples. These latter involve another mantle source, distinct from that of the amphibolites, and comparable to that of continental alkali basalts. These data indicate that the central part of the Maures Massif and the southern Massif Central were possibly part of the same pre-Variscan structural unit. The lack of evidence for a clear genetic relationship between the respective protoliths of the two end-members of the leptyno-amphibolitic complex raises once again the problem of the geodynamic significance of these formations.

Speciation by hybridization in insects has been recently recognized on the basis of isozyme and chromosome studies showing that several species, either diploid or polyploid, have genomes that combine the genes and chromosome sets of two (or more) bisexual species. Until this evidence became available, thelytokous invertebrates were all considered uniparental derivatives of bisexual species. In this paper, we review examples including the stick insects Bacillus whitei, B. atticus, B. lynceorum, Leptynia hispanica D, Clonopsis gallica, Carausius morosus; the grasshopper Warramaba virgo; some Otiorrhynchus weevils; the planthopper Muellerianella 2-fairmairei–brevipennis; and black flies of the genera Gymnopais and Prosimulium. For several species (e.g., Warramaba virgo and Bacillus whitei), both parental taxa have been recognized, and their hybrid origin has been genetically assessed. In others (e.g., B. atticus), only one of the bisexual parental species has been detected; but their hybrid origin is supported by strong evidence, at both the isozyme and chromosome levels. For other supposed hybrid species (e.g., Clonopsis gallica, Carausius morosus), no bisexual ancestors have been detected, possibly because competition with their hybrid derivatives has made them rare or extinct. Insect hybrid species may differ in their mode of reproduction (apomictic or automictic thelytokous parthenogenesis, gynogenesis), degree of ploidy, and genetic structure (level of heterozygosity, clonal variation). The parallels between insect and vertebrate hybrid species, in which this phenomenon has been recognized and widely studied in the past 50 years, are drawn. The main problems involved in the origin and evolution of hybrid species are discussed, with particular regard to (i) changes in the maturation divisions allowing the transmission of the hybrid genome to the next generation, and (ii) their successful adaptation. The "spontaneous" and "hybrid" theories for the origin of unisexual forms are compared, with regard to hybrid species. An origin of hybrid species from occasional parthenogenetic development of hybrid eggs produced in areas of extensive interspecific hybridization (e.g., disturbed habitats) is suggested. Hybridization would not itself cause changes in the maturation divisions (which are controlled by genes of tychoparthenogenetic eggs) but only favour their selection through heterosis. The role of the so-called "heterotic" advantage (resulting from high levels of heterozygosity) and "demographic" advantage (resulting from all-female reproduction) in the evolutionary success of hybrid species is discussed. It is concluded that habitat disturbance by man is favouring both the onset of hybrid species and their successful spread.

A complete taxonomic catalogue of the Stick and Leaf-insects (Phasmatodea) recorded or described from the mainland China (excluding Taiwan) is presented. 241 valid species are listed, which are currently attributed to 50 genera, 5 families and 7 subfamilies. Genera and species are listed alphabetically. All available type-data is provided based mainly on literary sources for species described by Chinese workers from 1986 to 2006, including documented depository of typespecimens. The catalogue therefore also provides complete lists of the type-material of Phasmatodea housed in the following Chinese institutions: Administration of Baishuijiang Natural Reserve (ABNR), Beijing Forestry University, Beijing (BFU), China Agricultural University, Beijing (CAU), Geological Museum of China, Beijing (GMC), Inca Science Ltd., Chongqing (INCA), Institute of Zoology, Chinese Academy of Sciences, Beijing (IZCAS), Department of Biology, Nankai University, Tianjin (NKU), Northwest Sci-Tech University of Agriculture and Forestry, Shaanxi (NWAU), Institute of Zoology, Shaanxi Normal University, Xi’an (SNU), Institute of Entomology, Sun Yat-sen University (ICRI), Shanghai Institute of Entomology, Academia Sinica, Shanghai (SIES), Tianjin Natural History Museum, Tianjin (TMNH), Zhejiang Museum of Natural History, Hangzhou (ZMNH). The known distribution of each species, inmeans of provinces is provided as well. 14 species are shown to have been recorded from China in error, several of these based on misidentifications. The “Phasmatodea-like” fossil taxa described from the Late Jurassic Yixian Formation of North Hebei and West Liaoning are listed in a separate section. Two new generic synonyms are recognized: Arthminotus Bi, 1995 synonymised with Lopaphus Westwood, 1859 (n. syn.) and Dianphasma Chen & He, 1997 synonymised with Parasosibia Redtenbacher, 1908 (n. syn.). The genus Linocerus Gray, 1835 (Type-species: Linocerus gracilis Gray, 1835) was erroneously synonymised with the mediterranean Bacillus St. Fargeau & Audinet-Serville, 1825 and is here re-established in Phasmatidae: Pachymorphinae: Gratidiini (rev. stat.). Relationship to Clonaria Stål, 1875 (= Gratidia Stål, 1875, = Paraclonaria Brunner v. Wattenwyl, 1893), Sceptrophasma Brock & Seow-Choen, 2000 and Macellina Uvarov, 1940 is obvious. 21 species are transferred to other genera (new combinations): Asceles dilatatus Chen & He, 2004 and Asceles quadriguttatus Chen & He, 1996 to Pachyscia Redtenbacher, 1908, Arthminotus sinensis Bi, 1995 to Lopaphus Westwood, 1859, Baculum dolichocercatum Bi & Wang, 1998 and Baculum politum Chen & He, 1997 to Medauroidea Zompro, 1999, Dixippus hainanensis Chen & He, 2002, Dixippus huapingensis Bi & Li, 1991, Dixippus nigroantennatus Chen & He, 2002, Dixippus parvus Chen & He, 2002 and Entoria bobaiensis Chen, 1986 to Lonchodes Gray, 1835, Sipyloidea obvius Chen & He, 1995 to Sinophasma Günther, 1940, Paramyronides biconiferus Bi, 1993, Paramyronides leishanensis Bi, 1992, Lonchodes chinensis Brunner v. Wattenwyl, 1907, Lonchodes confucius Westwood, 1859 and Phasgania glabra Günther, 1940 to Phraortes Stål, 1875, Gratidia bituberculata Redtenbacher, 1889 and Leptynia xinganensis Chen & He, 1993 to Sceptrophasma Brock & Seow-Choen, 2002, Prosentoria bannaensis Chen & He, 1997 to Paraentoria Chen & He, 1997, and Mantis squeleton Olivier, 1792 to Phanocloidea Zompro, 2002. Acrophylla sichuanensis Chen & He, 2001 remains of unknown generic assignment, but is shown to be not a member of the Australian genus Acrophylla Gray, 1835. Furthermore, as Baculum Saussure, 1861 is a neotropical genus and most Old World species previously attributed to this genus are now listed in Ramulus Saussure, 1861, all Chinese species described in Baculum Saussure are consequently transferred to Ramulus Saussure. Other changes of specific placements are based on published literature and concern to the following three synonymies not recognized by Chinese workers: Abrosoma Redtenbacher, 1906 (= Prosceles Uvarov, 1940), Necroscia Audinet-Serville, 1838 (= Aruanoidea Redtenbacher, 1908), Lopaphus Westwood, 1859 (= Paramyronides Redtenbacher, 1908). Megalophasma Bi, 1995 is transferred from Necrosciinae to Lonchodinae. Four lectotypes are designated and three new specific synonyms revealed. A lectotype is designated for Rhamphophasma modestus Brunner v. Wattenwyl, 1893, the type-species of Rhamphophasma Brunner v. Wattenwyl, 1893, in order to fix this genus and species. The male paralectotype is shown to be a male of Parapachymorpha nigra Brunner v. Wattenwyl, 1893, the type-species of Parapachymorpha Brunner v. Wattenwyl, 1893. Clitumnus porrectus Brunner v. Wattenwyl, 1907 is synonymised with Bacillus ? artemis Westwood, 1859 and a lectotype designated for the former (n. syn.). A lectotype is designated for Oxyartes lamellatus Kirby, 1904 in order to fix this taxon and confirm the synonymy established by Dohrn, 1910 (= Oxyartes honestus Redtenbacher, 1908, = Oxyartes spinosissimus Carl, 1913). Paracentema stephanus Redtenbacher, 1908 is shown to have been erroneously synonymised with Neohirasea japonica (de Haan, 1842) and here synonymised with Neohirasea maerens (Brunner v. Wattenwyl, 1907) (n. syn.). In order to fix this new synonymy a lectotype is designated for Paracentema stephanus Redtenbacher, 1908. Finally, a biogeographic analysis of the Chinese phasmid fauna is presented. This includes brief background information on the topography and biogeography of China along with maps showing the seven zoogeographical subregions currently recognized as well as the 4 municipalities, 23 provinces, 5 autonomous regions and 2 special administrative regions of China. A summary of the taxonomic compilation of the fauna is provided and its relationships with neighbouring regions, of both the Palaearctic and Oriental realms, are discussed. A study is presented on the distribution of the taxa and species densities of each province / autonomous region. Recent ecological studies are summarized and list of the host plants of 42 different species attached. The pest status of certain species which have become of serious importance for agriculture in China is briefly summarized based on literary sources.

ResumoO Museu Casa de Rui Barbosa, cuja construção foi feita no ano de 1850, localiza-se no bairro de Botafogo na cidade do Rio de Janeiro e faz parte da Fundação Casa de Rui Barbosa tombado pelo IPHAN. O edifício que abriga o Museu foi residência de Ruy Barbosa de Oliveira que dentre outras atribuições foi um jurista, escritor e político brasileiro de grande importância para o país. Devido a importância de cunho histórico e cultural de sua residência, o objetivo do presente trabalho é a caracterização e a avaliação da alterabilidade das rochas das fachadas da Casa de Rui Barbosa por meio de ensaios não destrutivos in situ. Para tal, foram realizados ensaios de avaliação de dureza, análise química por meio da fluorescência de raios-X portátil (FRX) e colorimetria. Foi feito também o mapeamento litológico, identificação das morfologias de alteração e amostragem da água de lavagem de locais alterados para avaliação química dos sais e sujidades utilizando técnica de espectrometria ICP-OES e análise de pH. A maioria das rochas ornamentais das fachadas são, possivelmente, gnaisses leptiníticos, e alguns apresentam alterações como modificação cromática, perda de massa, fissuras e esfoliação, porém há ainda a presença de gnaisses facoidais. A análise de FRX corrobora com a hipótese das rochas serem leptinitos devido ao alto teor de silício (50- 85%) e alumínio (12-32%), além de ferro (1-5%), indicando presença de granada almandina. Foi possível observar que há uma leve alteração cromática nos corpos avaliados. A análise química das águas de lavagem apresentou teores consideráveis de íons sódio e cloro, ambos com cerca de 7 mg.L-1, que podem estar relacionados com a proximidade do Museu à Baía de Guanabara, e enxofre com valores de S-2 e SO4-2, superior a 70 mg.L-1 e 140 mg.L-1, respectivamente, podendo estar relacionado à poluição oriunda do intenso tráfego de veículos na rua em que se encontra a casa. Os resultados apontam que existe um processo de degradação contínuo destas rochas, sendo influenciado por fatores climáticos e, também, pela sua localização.Palavras Chave: rochas ornamentais, alterabilidade, Museu Casa de Rui BarbosaAbstractALTERABILITY EVALUATION OF THE ROCK FACADE FROM CASA DE RUI BARBOSA MUSEUM. Casa Rui Barbosa Museum, was built in 1850, located in Botafogo in the city of Rio de Janeiro, and part of Foundation Casa de Rui Barbosa - IPHAN. The building was the residence of Ruy Barbosa de Oliveira who among other duties was a lawyer, a writer and a politician of great importance to Brazil. Because of the importance of historical and cultural nature, the aim of this study is the evaluation of the alterability of the stones of the facades of the Casa Rui Barbosa Museum through non-destructive testing in situ, hardness evaluation, chemical analysis by fluorescence-ray portable X (FRX) and colorimetric analysis. Also the lithological mapping, identification of alterability and chemical evaluation of the salts and dirtiness of the wash water using ICP-OES spectrometry, moreover pH analysis. Most ornamental stones of the facades are possibly leptynite, and some feature changes such as color change, weight loss, cracks and exfoliation, but there is still the presence of augen gneisses. The XRF analysis supports the hypothesis that stones are leptynite due to the high silicon content (50-85%) and aluminum (12-32%), and iron (1-5%), indicating the presence of almadine garnet. A slight color change was observed in the stones. Chemical analysis of the water showed significant levels of sodium and chloride ions, both with approximately 7 mg.L-1, which may be related to the proximity of the Guanabara Bay, and high values of S-2and SO4-2, above 70 mg.L-1and 140 mg.L-1, respectively, and may be related to pollution from the heavy vehicle traffic on the street where the Museum is located. The results showed that there is a continuous degradation process of these stones, influenced by weathering and the location.Keywords: dimension stones, weathering, Casa de Rui Museum