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Sr-Nd-Pb isotopes of Tertiary volcanics of King George Island, Antarctica

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Chinese Science Bulletin 1997年第22期42卷 1913-1918页

作者： Xing, GF Shen, WZ Wang, DZ Jin, QM Nanjing Inst Geol & Mineral Resources Nanjing 210016 Peoples R China

1 Geological settingThe King George Island is the largest one in South Shetland Islands, West Antarctica,with an area of 1200 km^2. Most of it is covered by ice and snow all the year round. It consistsmainly of Tertia... 详细信息

关键词： Sr-Nd-Pb isotopes Tertiary volcanics King George Island Antarctica.

Currawang Cu-Pb-Zn massive sulfide deposits in basic volcanics, New South Wales, Australia

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Chinese Science Bulletin 1999年第S2期44卷 54-55页

作者： Brian Marshall Mark Bouffler T.HO Department of Applied Geology University of Technology Sydney New South Wales 2007 Australia Woodlawn Mines PO Box 141 Goulburn NSW 2580 Australia

1 Geology THE Currawang deposit is situated in the Canberra-Goulburn district, near the Woodlawn deposit, and isone of a large number of the massive sulfide deposits of base metal located in the late Silurian volcanics,New South Wales. The Currawang deposit is a vein type deposit in basic volcanics, different from otherdeposits in the Canberra-Goulburn district which are the felsic-volcanics-hosted deposits and belong toVMS. The Currawang deposit as two lenses (the south lens and the north lens) that occurred in the basicvolcanics consisted of pillow basalt, massive basalt, with agglomerate, tuff and dolerite. The constituentsof the basalt are amphibole, chlorite, feldspar, pyroxene, epidote, leucoxene, ilmenite, magnetite,

关键词： Currawang Cw-Pb-Zn deposit massive sulfide deposit basic volcanics New South Wales.

Geochemical Constraints of the Ediacaran Volcano-Sedimentary Succession of the Sa'al Metamorphic Complex at Wadi Zaghra, South Sinai, Egypt

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Acta Geologica Sinica(English Edition) 2019年第1期93卷 50-73页

作者： SAMUEL D.Michael MOUSSA E.Hilmy AZER K.Mokhles SADEK GHABRIAL Doris Geological Sciences Department National Research Centre (NRC)

The volcano-sedimentary succession around Wadi Zaghra in Sinai, at the northernmost segment of the Arabian Nubian Shield, comprises volcanic rocks interbedded with rather immature sediments. The succession is dominated by intermediate to silicic volcanics of medium-to high-K calc-alkaline affinity. It is divided into two units, the lower unit includes intermediate rocks and dacites interbedded with graywackes, semi-pelites and pelites and topped by polymict conglomerates. This unit is subjected to folding and regional metamorphism(up to garnet zone) and is intruded by quartz diorite-granodiorite inducing, locally, low-pressure contact thermal metamorphism. The unmetamorphosed upper unit encompasses acid volcanics intercalated with litharenite, sublitharenite and minor arenite. The rhyolites of this unit pertain to the highly fractionated granites and are characterized by an agpaitic index(NK/A) ranging from 0.87 to 0.96. They may reflect either extensive interaction of subduction-related magmas with the continental crust or a change in the tectonic regime. The present lithological and geochemical characteristics of the studied sediments together with available zircon ages indicate rather distal provenance of their detritus. This detritus comprises fluvial-alluvial sediments accumulated in the intermontane basins, which are half-grabens or tilted fault blocks. The tectonic setting of the depositional basins is active continental margin and continental island arcs. Geochemical patterns of the Zaghra volcano-sedimentary succession indicate their correlation with the Dokhan volcanics-Hammamat Clastics sequence of the Eastern Desert of Egypt. Also, the Zaghra volcanics display geochemical similarities with those exposed in Sinai, at the Rutig, Ferani and Iqna Shar'a areas. The Zaghra succession is dated as Ediacaran but is not related either to the ensimatic island arc assemblage or to the rift-related assemblage formed during the early stages of the break-up of Rodinia as previously thought.

关键词： geochemistry Neoproterozoic Dokhan volcanics Arabian-Nubian Shield Sinai Egypt

Genetic Mechanism of Dolomitization in Fengcheng Formation in the Wu-Xia area of Junggar Basin,China

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Acta Geologica Sinica(English Edition) 2012年第2期86卷 447-461页

作者： ZHU Shifa ZHU Xiaomin NIU Huapeng HAN Xuefang ZHANG Yueqian YOU Xincai State Key Laboratory of Petroleum Resource and Prospecting Beijing 102249China College of Geosciences China University of Petroleum(Beijing)Beijing 102249China Tianjin Exploration and Development Research Institute CNOOCTianjin 300452China Research Institute of Petroleum Exploration and Development Xinjiang Oilfield CompanyCNPCKaramayXinjiang 834000China

The dolomitic rocks of the Fengcheng Formation are considered to be formed under special geologic conditions, and are significant hydrocarbon reservoir rocks in the Wu-Xia area in the Junggar Basin. Analyses of petrologic characteristics and stable isotope composition indicate that the dolomitizing host rock is volcanic and the dolomitizing fluids probably consists of brine from shore- shallow lakes with great evaporation and salinity in the Fengcheng Formation, which have formed under arid climatic conditions, as well as residual Mg-rich seawater from the underlying Jiamuhe Formation and Carboniferous. Dust tuff in the area has significant plagioclase content. Anorthite and labradorite hydrolysis by CO2 can be coupled with calcite precipitation. Late Mg-rich brine percolated and replaced calcite formed in the early time, which lead to precipitate dolostones with different occurrences, such as graniphyric, random bedded or lumpy. The diagenetic dolostones with different occurrences resulting from particular formation conditions occurred in different tectonic settings. The dolomitizing fluid has been driven by the thermal convection flow generated by volcanic eruptions. At the same time, the overthrusts of the Wu-Xia growth fault have speeded up the flow of deep Mg-rich water upwards, and induced the water to quickly penetrate and horizontally migrate in the strata. Fracture is the major and the most important reservoir space in dolomitic reservoir of the Fengcheng Formation. Fracture and fault plays a decisive role in controlling the formation of dolostone and the distribution of favorable reservoirs. The deliverability of oil and gas is determined by the development and match relations of dissolved pores and fractures to a certain degree.

关键词： diagenetic dolostone volcanics fracture Fengcheng Formation Junggar basin

Petrogenesis of Cenozoic Volcanic Rocks in Tengchong Region of Western Yunnan Province,China

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Science China Chemistry 1994年第10期37卷 1264-1271页

作者：从柏林陈秋媛张儒瑷吴根耀徐平 Institute of Geology Academia SinicaBeijing 100029PRC Deptartment of Geology University of Illinois1301 West Green St.UrbanaIL 61801USA Deptartment of Geology Stanford UniversityCA94305-2115USA

The Tengchong Cenozoic volcanic rocks belong to the high-K calc-alkaline rock series.They are strongly depleted in high field strength (HFS) elements and enriched in large-ion lithophile(LIL) elements and LREE.The generation of Tengchong volcanic rocks has been considered to be relatedto the evolution of the Neo-Tethys.The Indian Plate was subducted beneath the southeastern Asia conti-nent,which resulted in the formation of Indo-Burman Arc in the Late Cretaeeous-Palaeocene time.Thecollision between the Indian continent and Indo-Burman Arc started in Eocene and lasted to the present.The Andaman Sea and the Inner Burman Tertiary Basin are a back-arc basin that has been extended sincethe Late Miocene.A distinct characteristic of Tengchong volcanics is that they show a chemical affinityrelated to island arc but their generation postdated the subduetion of the ocean plate.

关键词： Cenozoic volcanics island arc affinity Tethys Tengchong

Paleomagnetism　of　Early　Tertiary　volcanics　in　the　South　Shetland　Islands　and　its　tectonic　implications

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Chinese Journal of Polar Science 1995年第2期6卷 18-29页

作者：刘坚葛同明段威武吴能友

A total of 334 oriented volcanic samples of Early Tertiary were collected for a paleomagnetic study from 43 sampling sites in the South Shetland Islands,Antarctica.Paleomagnetic study indicates that the South Shetland Islands and Antarctic Peninsula were situated in or close to their present position in Early Tertiary. Furthermore, it is also suggested that a counterclockwise rotation about 15 degrees related to the relative movement between South America and Antarctica took place in north of Antarctic Peninsula since Paleocene.

关键词： South Shetland Islands Early Tertiary volcanics paleomagnetism.

Silurian to Devonian foreland basin in the south edge of Tarim Basin

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Chinese Science Bulletin 2002年第S1期47卷 42-46页

作者： WEI Guoqi JIA Chengzao LI Benliang CHEN Hanlin Langfang Branch Research Institute of Exploration and Development PetroChina Langfang 065007China PetroChina Company Limited Beijing 100011China Earth Science Department Zhejiang UniversityHangzhou 310013 China

Based on the theory of plate tectonics, combin-ing with the isotopic dating of ophiolite, igneous and volcan-ics, geochemical test, rare earth element analyze and seismicinterpretation, this paper studies the pre-Carboniferous tec-tonics and sedimentary formation of the south edge of theTarim Basin and proves that there exists the Kunlun Oceanunder tensional tectonics during the Sinian and Cambrian inthe south edge of the Tarim Plate. After that, due to the colli-sion orogenesis, there formed the peripheral foreland basinin the south edge of Tarim. The Upper Silurian and Devo-nian molasses sedimentary system superposed on the Sinianand Middle Silurian passive margin flysch sedimentary sys-tem and formed the bivariate structure of the foreland basin.And at the same time, based on the field geology and seismicinterpretation, we have identified that the formation of theSilurian and Devonian have the character of half depositwhich shows thick in the south area and thin in the north,and the pre-Carboniferous thrust compression tectonics re-mained in the foreland thrust belt, which further demon-strates that there existed the Silurian and Devonian periph-eral foreland basin on the south edge of the Tarim Basin.

关键词： Tarim Basin ophiolite igneous volcanics peripheral foreland basin foreland thrust belt.

The Records of the Tectonic Evolution From the volcanics in Qiangtang Basin,Tibet

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Global Geology 2000年第1期5卷 61-69页

作者： He Zhonghua Yang Deming Li Cai Pu Zhongyu Jilin University Changchun 130026 P.R.China The Exploration andDevelopment Institute of Liaohe Oil&Gas Sub-company Panjin Liaoning Province124010 P.R.China

The volcanism in Qiangtang Basin is very frequent due to the divergence and subduction of the various plates.The study indicates that these volcanics are formed in different tectonic settings:1)Hercynian volcanics are mainly basalts and are formed in the intraplate and intercontinental rift.2)Indosinian volcanics markedly vary in the distribution and composition and reflect transitional MORB and island arc environments respectively.3)Yanshanian volcanics consist predominantly of basalts,andesites,dacites and rhyolites and are characterized by calc-alkaline volcanic suite, indicating island arc setting.4)Himalayan volcanics are complicated and associated with intraplate orogency.The volcanism provides important tectonic information for recognizing the evolution of Qiangtang Basin.

关键词： volcanics tectonic information evolution Qiangtang Basin

Evidences for Incipient Hydrothermal Event(s) in the Central Indian Basin: A Review

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Acta Geologica Sinica(English Edition) 2005年第1期79卷 77-86页

作者： Sridhar D. IYER National Institute of Oceanography Dona Paula Goa 403 004 India

The Central Indian Basin (CIB, 10°-19°S) encompasses morphotectonic features such as seamounts, abyssal hills, faults, fracture zones and lineations and basic to silicic volcanics that were derived from different sources. Instances of incipient hydrothermal event (s) occurred as evident from: (1) spilites that probably formed due to low-temperature hydrothermal action on the precursory basalts, (2) slabs and fragments of zeolitites which are the consequent products of palagonitization of the basaltic glasses, (3) chemical variations in the ferromanganese crusts, and (4) abundance of volcanogenic-hydrothermal material (vhm) that includes ochrous sediments and magnetite spherules. The vhm suggests its origin by interaction of Fe-rich hydrothermal solutions with surrounding sediments. The CIB spherules occur in sediments of~10 ka and ~425 to 650 ka age and are orders of magnitude younger than the 50 to 60 Ma age of the basin. Incidentally, to the north of the basin at ODP Site 717-719(1 °S/81 °E) hydrothermal precipitates of inorganic calcite and deposition of sulphide minerals (~7.5 to 9 Ma and 0.5 Ma) occur as a result of the on-going intraplate deformation. This paper reviews the above evidences that possibly indicate episodes of localized hydrothermal events in the CIB.

关键词： Central Indian Basin morphotectonics volcanics hydrothermal events synopsis