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1.
Evidence for a mantle and/or basaltic component in KT boundary distal ejecta is apparently inconsistent with ejection from Chicxulub Crater since it is located on~35km thick continental crust(De Paolo et al.,1983;Montanari et al.,1983;Hildebrand and Boynton,1988,1990).This evidence,along with ejected terrestrial chromites(Olds et al.,2016)suggest the impact sampled terrestrial mafic and/or ultramafic target rocks which are not known to exist in the Chicxulub target area.Possible resolutions to the paradox are:1)the existence of an unmapped/unknown suture in Yucatan Platform basement,2)an additional small unmapped/unknown impact site on oceanic lithosphere,or 3)an additional large impact on oceanic lithosphere or continental margin transitional to oceanic lithosphere.The third hypothesis is elaborated here since:1)Ophiolites nearest to Chicxulub crater are found in Cuba and apparently were obducted in latest Cretaceous/earliest Danian times(García-Casco,2008),inconsistent with the documented Eocene collision of Cuba with the Bahamas platform;and 2)Cuba hosts the world’s thickest known KT boundary deposits(Iturralde-Vinent,1992;Kiyokawa et al.,2002;Tada et al.,2003).These and geometric considerations suggest oceanic crust and upper mantle rock,exposed as ophiolite in the Greater Antilles island chain,marks the rim of a roughly 700 km diameter impact basin deformed and dismembered from an originally circular form by at least 50 million years of left-lateral shear displacement along the North American-Caribbeantransform plate boundary. 相似文献
2.
《Scientia Geologica Sinica》2001,(2)
The Hongliuguo-Lapeiquan mélange (Fig. 1) is seen in the Altyn fault belt (AFB), which is a large-scale sinistral strike-slip fault belt in the central Asia and also a part of the north natural boundary of the Qinghai-Tibetan plateau, separating the Tarim basin from the Qaidam basin (Zheng Jiandong, 1988; Avouac et al., 1993; Chalaron et al., 1995; Ge Xiaohong et al., 1998; Cui Junwen et al., 1996, 1997, 1999; Wang Yan et al., 1999). This mélange extends eastward from Hongliuguo thro… 相似文献
3.
Zircon SHRIMP Dating for the Weiya Pluton, Eastern Tianshan: Its Geological Implications 总被引：18，自引：4，他引：18
ZHANG Zunzhong GU Lianxing WU Changzhi LI Weiqiang XI Aihua WANG Shuo State Key Laboratory of Mineral Deposit Research 《《地质学报》英文版》2005,79(4):481-490
1 Introduction Voluminous literature has resulted from study of the geology and tectonic evironments of post-orogenic granitoids in eastern Tianshan (He et al., 1995; Han et al., 1997; Gu et al., 1999, 2001; Li et al., 2003; Chen et al., 2004). Previous contributions (Hu et al., 1997; Li et al., 2003) indicate that major events of continental collision in northern Xinjiang occurred around 300 Ma. Then, the tectonics converted from compression to extension, resulting in the uplifting of th… 相似文献
4.
Jonathan C. AITCHISON 《《地质学报》英文版》2017,91(Z1):1-2
Throughout the Phanerozoic the eastern margin of Gondwana and related fragments such as New Caledonia and New Zealand that are now dispersed from it grew through the addition of ophiolites and associated intra-oceanic island arc assemblages.Exactly how and why this occurred remains controversial with two main competingmodelsreferredtoaseither‘quantum’or‘accordion’tectonics.The quantum model envisages continental growth through the additional of discrete intra-oceanic assemblages analogous to contemporary tectonic settings in Taiwan,Timor and Papua New Guinea(Aitchison and Buckman,2012).The alternative regards eastern Australia as the type example of a different style of convergent plate margin referred to as an‘extensional accretionary orogeny’(Collins,2002).The oldest Phanerozoic ophiolites and intra-oceanic island arc assemblages are of Cambrian age and are widely reported from the Lachlan Fold Belt in the eastern Australian states of Victoria and NSW(Spaggiari et al.,2003;Greenfield et al.,2011).Similar rocks are also known from Mount Read in Tasmania(Berry and Crawford,1988;Crawford and Berry,1992;Mulder et al.,2016),the Weraerai terrane and its correlatives in the New England orogen further east in northeastern NSW(Aitchison et al.,1994;Aitchison and Ireland,1995)and Queensland,the Takaka terrane in NW Nelson,New Zealand(Münker and Cooper,1999)and the Bowers terrane in Northern Victoria Land,Antarctica(Weaver et al.,1984;Münker and Crawford,2000;Rocchi et al.,2011;Palmeri et al.,2012).The Late Ordovician saw the development of the intra-oceanic Macquarie island arc(Glen et al.,1998;Glen et al.,2007).This system contains important economic mineral deposits.The way in which these arcrocks developed and were juxtaposedagainst a surrounding suite of Lachlan Fold Belt,eastern Australia remains the subject of investigation(see Aitchison and Buckman,2012 for discussion).In a similar area,enigmatic rocks of the Tumut ophiolite also crop out(Graham et al.,1996;Belousova et al.,2015).Further to the east in the New England orogeny Siluro-Devonian rocks of the Gamilaroi terrane and it’s along strike correlatives near Mt Morgan in Queensland represent another intra-oceanic island arc assemblage emplaced onto the Gondwana margin in the Late Devonian(Aitchison and Flood,1994;Offler and Murray,2011).The Late Carboniferous-Permian saw development of significant intra-oceanic island arc and ophiolitic complexes remnants of which crop out in New Zealand,eastern Australia,and New Caledonia.These include the Brook Street terrane(Spandler et al.,2005;Mc Coy-West et al.,2014)and Dun Mountain Ophiolite Belt in New Zealand(Coombs et al.,1976;Stewart et al.,2016),the Gympie terrane in southeast Queensland(Waterhouse and Sivell,1987;Sivell and Waterhouse,1988)and the Koh terrane in New Caledonia(Meffre et al.,1996;Ali and Aitchison,2002).The youngest on-land association of ophiolitic and intra-oceanic island arc rocks in the region is of Eocene age.Ultramafic rocks are well exposed in New Caledonia where they structurally overlie continental rocks of Gondwana margin affinity that,in the northeast of the island,have experienced eclogite facies metamorphism(Aitchison et al.,1995).The emplacement of these rocks was a widespread regional event with potentially correlative rocks exposed in Papua New Guinea(Parrot and Dugas,1980)as well as Northland and East Cape in New Zealand(Whattam et al.,2005;Whattam et al.,2008). 相似文献
5.
《Scientia Geologica Sinica》2000,(3)
1. IntroductionThe discovery of delicately persevered multicellular algae and possible animal embryos from the terminal Proterozoic Doushantuo Formation has greatly changed our views on the origin and early evolution of metaphyte and metazoan (Chen et al., 1991, 1992; Zhang et al., 1992, 1998; Li et al., 1997; Xiao et al., 1998), and encourages us to look for the evidences of advanced lives in older rocks. Some jellyfish fossils were reported in the Piyuancun Formation (equated with Dengyi… 相似文献
6.
Yoshihito KAMATA 《地球学报》2009,30(Z1):19-20
In the last decade, radiolarian biostratigraphy has clarified the ages of siliceous sedimentary rocks in vari-ous parts of Thailand (e.g., Sashida et al., 1993; Ka-mata et al., 2002; Wonganan and Caridroit, 2005). These age determinations have yielded not only new litho- and chronostratigraphic interpretations, but also data on the time duration and spatial distribution of the Paleo-Tethys and its associated seaways. Recently, Kamata et al. (2009) has classify the chert into two types of “pelagic” and “hemipelagic” based on lithol-ogy, faunal content, and stratigraphy in Thailand, and presumed that the pelagic environments of the Pa-leo-Tethys would have been suitable for the deposi-tional site for the former whereas the vicinity of a continental slope and rise located in the eastern margin of the Sibumasu would have been suitable for the latter. Kamata et al., (2009) also clarified that the hemipale-gic and pelagic cherts are exposed in two north- trending zones. The western zone includes the hemipelagic chert, as well as glaciomarine and other Paleozoic to Mesozoic successions, overlying a Pre-cambrian basement of Sibumasu elements. The eastern zone contains pelagic chert and limestone and should be correlated to the Inthanon Zone (Ueno, 1999; 2002). The Inthanon zone is characterized by the presence not only of Paleo-Tethyan sedimentary rocks, but also of Sibumasu elements that structurally underlie the Pa-leo-Tethyan rocks. The boundary between the Sibu-masu and Paleo-Tethys zones is a north-trending, low-angle thrust that resulted from the collision of the Sibumasu and Indochina Blocks (Ueno, 2002; Kamata et al., 2009) 相似文献
7.
Toshifumi KOMATSU Reishi TAKASHIMA TA Hoa PHUONG Tran Huyen DANG Duc Phong NGUYEN Huu Hung NGUYEN Satoru KATO Kento HIRATA Takumi MAEKAWA 《地球学报》2012,33(S1):38-38
The Pho Han Formation is exposed on southern Cat Ba Island, Hai Phong Province in northeastern Vietnam, and intercalates the Devonian and Carbonif-erous (D-C) boundary (Ta and Doan, 2007; Komatsu et al., 2012). The D-C boundary section consists mainly of limestone beds, numbered from 1 to 167, interca-lated with alternating black organic-rich shales. The limestone yields abundant brachiopods, crinoid-stems and conodonts. Preliminary investigations on strati-graphy (conodont biostratigraphy and δ13C) and sedi-mentology of beds 113-133 were undertaken in this study. 相似文献
8.
CHEN Bin LIU Shuwen WANG Rui CHEN Zhichao LIU Chaoqun Key Laboratory of Orogenic Belts Crustal Evolution MOE School of Earth Space Sciences Peking University Beijing 《《地质学报》英文版》2006,80(6)
1 Introduction The tectono-thermal evolution of the North China Craton (NCC) in Late Archean to Paleoproterozoic times has long been attractive to many researchers (Wan et al., 2000; Zhao et al., 2000, 2002; Guo et al., 2001; Liu et al., 2002; Zhai and Liu 2003; Zhai, 2004; Yu et al., 2004; Kr?ner et al., 2005; Wilde et al., 2005). Zhao et al. (2000, 2002) proposed a tectono-thermo framework for the evolution of the NCCbased on detailed petrological and geochronological data, and they … 相似文献
9.
《Scientia Geologica Sinica》2000,(3)
1. IntroductionThe discovery of the ophiolites (composed of mafic-ultramafics plutons, radiolarian silicalites and the basic metavolcanic rocks) in Mianlue zone was one of the most important progresses in the study on Qingling orogen in recent years (Zhang G W et al., 1995, 1996; Zhang Z Q et al., 1996; Yin et al., 1998; Lai, 1997; Lai et al., 1996; Meng et al., 1999). Many geologists got the conclusions as followings. (1) along the Mianlue zone, the oceanic crust developed in late Paleoz… 相似文献
10.
Data on the carbonate content in marine sedi-ments are one of the most i mportant proxies to paleo-ceanography,paleoenvironment,and paleocli mate.Itis directly related to the changes in the global carbonreservoir and has unique significance and wide appli-cations in both scientific research and resource explo-ration(Huang et al.,2003;Chen et al.,2002;Trentesaux et al.,2001).The data on the carbonatecontent in sedi ments are pri marily acquired by meas-uring core samples(Fabricius,2003;Kenter… 相似文献