Ophiolites and Intra-Oceanic Island Arc Assemblages of Eastern Australia, New Caledonia and New Zealand

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).     

Separation of nano-colloids in soils

The study of the physicochemical behaviour of colloids and particles in nature has emerged as a scientific problem of critical importance because of the widespread acknowledgement of their significance in controlling the speciation and fate of essential nutrients and contaminants in the aquatic and soil environments （Ledin et al., 1995; Lead et al., 1999, Doucet et al., 200 l; McCarthy et al., 1989; Koterba et al., 1993; Kretzschmar et al., 1999）. Se＇quaris and Lewandowski （2003） developed a method based on sedimentation and centrifugation steps to fractionate agricultural top soils after suspension in water. However, progress in the field has been limited by the lack of appropriate techniques for the isolation and characterization of colloids and particles in their native form （Lead et al., 1997）. The primary difficulties in separation and analysis are colloidal instability and their small size and low concentration. As a result, reliable, unbiased and minimally perturbing methods for sampling and fractionation are primary requirements for the study of colloids and particles if valuable information is to be obtained. In recent years, cross-flow ultra-filtration （CFUF） has become one of the most commonly used techniques for collecting and separating freshwater and marine colloids and particles （Petrus evski et al., 1995; Gustafsson et al., 1999; Benoit et al., 1999; Sigg et al., 2000; Gue＇guen et al., 2002; Benedetti et al., 2003）. CFUF has hitherto been used for studies of the biogeochemical cycling of a variety of elements, such as carbon （Benner et al., 1992; Santschi et al., 1998）, radionuclides （Moran et al., 1992）, trace metals （Reitmeyer et al., 1996） and nutrients （Bauer et al., 1996）. The purpose of this study was to develop a protocol to fractionate particles in soil, to measure particle size distributions and to quantify chemical characteristics within different particle size fractions.     

CONULARIID-LIKE FOSSILS FROM THE DOUSHANTUO FORMATION, NANGAOSHAN, WUNING, JIANGXI PROVINCE

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…     

http://www.sciencedirect.com/science/article/pii/S167498711400156X

<正>Continental reconstructions in Central Asia are represented by orogenesis along some large orogenic belts in the Altaid collage(Fig.1)or Central Asian Orogenic Belt(CAOB),which separate the East European and Siberian cratons to the north from the Tarim and North China cratons to the south(Sengor et al.,1993;Jahn et al.,2004;Windley et al.,2007;Qu et al.,2008;     

Stratal Carbonate Content Inversion Using Seismic Data and Its Applications to the Northern South China Sea

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…     

Clinopyroxene-melt Equilibrium of Cenozoic Basalts in Kuandian, Hannuoba and Mingxi areas, Eastern China and Its Importance

1. Introduction The depth of source of Cenozoic basalts and the genesis of mantle xenoliths in eastern China have been widely discussed by many geoscientists. There were basically two main opinions: one was that the relationship of basalts and the peridotite xenoliths are melt and residues (Cong et al, 1982; Liu et al, 1985; Qiu et al, 1986; E et al, 1987; Chi et al, 1988; Deng et al, 1988), and pyroxenite and gabrro enclaves are accumulation of fractional crystallization (Qiu et al, 1986;…     

THE MIANLUE TECTONIC ZONE IN SOUTH QINGLING AND ITS GEOLOGICAL SIGNIFICANCE

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…     

A Combined-Power Model for the Distribution of Axial Force in Shaft Anchor along Its Length

INTRODUCTIONThe anchorage of geomaterial , including shaftanchors and prestressed tendons ,is usually used ingeotechnical engineering. Owing to various advanta-ges ,these two anchorage types are widely used instructures in China ( Cao et al ., 2003 ; Fu et al .,1999 ;Lu et al .,1998 ; Li et al .,1995) . Shaft an-chors can be classifiedinto three kinds by the forceinthe shaft and cement grout :tensile ,press ,and sheartype (Lu et al .,1998) . The tensile type is the mostpopular in China…     

A Preliminary Report on Yong''''anpu Tectonic Window in Suizhong County, Western Liaoning Province

Several thrust faults have been mapped in theYanshan belt ,as the thrust structure was first iden-tified by Wong (1928) (Ji et al .,2005 ; Wang et al .,2005a ;Davis et al .,2001 ,1998 ; Yang et al .,2001 ;Zheng et al ., 2000 ; Chen, 1998 ; Zhang et al .,1986 ; He ,1957 ;Chern and Hsiung,1935) .Becausethe Archean basement was widely involved in thethrust systemof the Yanshan belt ,domestic popularrecognition emphasized the thick-skinned characteris-tics and li mited horizontal displacement…     

Impact,Mechanism,Monitoring of Land Subsidence in Coastal Cities(Annual Work of IGCP 663)

正Land subsidence is a worldwide geohazard consisting in the lowering of the ground surface due to natural and human-induced processes occurring in the shallow and deep subsoil.Over the last two decades,land subsidence has caused damages and widespread impacts to a variety of infrastructures in coastal cities (Ma et al.,2011;Liu et al.,2016;Minderhoud et al.,2018).Meanwhile,it is particularly alarming as it reduces the ground     

Geochronology of Granitoid Rocks and Geochemistry,Petrogenesis of Volcanic Rocks in the Dahalajunshan Formation Towards a Genetic Model for the Associated Iron Ore Deposits,Xinjiang, NW China

<正>There are many skarn deposits that occur in volcanic rocks as stratiform and lentoid bodies,for example the Lower Yangtze River Valley,Western Tianshan Mountains and Lhasa Terrane in China,the Nuuk in West Greeland and the Austroalpine Alps(e.g.Xv et al.,1984;Appel,1994;Raith and Stein,2000;Wang et al.,2001;Gu et al.,2007;Hou et al.,2011;Zhou et al.,2011;Jiang et al.,2012;Xu et al.,2010;Wang et al.,2012;Yu et al.,2011).Despite     

辽西建昌县玲珑塔含翼龙和带羽毛恐龙化石地层层序和时代归属

最近辽西建昌地区报道发现了一系列带羽毛恐龙和翼龙化石, 其赋存化石的地层层位时代一直富有争议。我们结合前人资料对玲珑塔含化石地层剖面进行了野外调查和实测, 厘定了含化石地层沉积层序和时代归属。剖面顶底岩石组合特征主要以溢流相中性熔岩和近火山口相火山碎屑岩为主, 中间层位为河流相-湖泊相碎屑岩。该剖面产有大量叶肢介、介形类、双壳类、昆虫、鱼类、植物化石和大量脊椎动物化石。上述化石指示含恐龙化石地层时代为中侏罗世。通过区域对比认为含恐龙化石地层与区域上髫髻山组地层层序和岩石组合相似, 因此认为含恐龙化石地层为中侏罗世髫髻山组(火山岩同位素年代学年龄范围为152~165 Ma)。     

INDIA/ASIA CONVERGENCE AND HIMALAYAN SHORTENING

INDIA/ASIA CONVERGENCE AND HIMALAYAN SHORTENING     

Geological evolution of the tethys belt from the atlantic to the pamirs since the LIAS

We discuss nine palinspastic geological maps (Plates 1–9), at scale, which depict the evolution of the Tethys belt from the Pliensbachian (190 Ma) to the Tortonian (10 Ma). A Present structural map (Plate 10) is shown for comparison at the same scale with the same conventions. Our reconstructions are based on a kinematic synthesis (Savostin et al., 1986), a paleomagnetic synthesis (Westphal et al., 1986) and geological compilations and analyses concerning in particular the western domain (Ricou et al., 1986), the eastern passive margins (Kazmin et al., 1986a), the eastern active margins (Kazmin et al., 1986b), the Black Sea-Caspian Sea basins (Zonenshain and Le Pichon, 1986) and the ophiolites (Knipper et al., 1986).     

浙江省东阳晚白垩世早期新的翼龙足迹

本文报道了浙江东阳发现的中国第2个翼龙足迹化石点, 也是亚洲发现的第8个翼龙足迹化石点。化石足迹产于晚白垩世早期方岩组的紫红色泥质粉砂岩中。发现有3个手的印迹和1个右足印。手的印迹的长宽分别为6.5 cm 和4cm. 非对称具有3个指的印迹。足迹9 cm长和1.5 cm宽。该足迹不同于以前发现的, 可能代表一新的类型。除了翼龙足迹外, 还发现鸟类、小型兽脚类、鸟脚类及蜥脚类脚印, 形成一个丰富的动物群, 它的发现为研究该地区的古生态环境及古地理具有重要意义。同时为以后在该地区发现这些造迹动物的骨骼化石提供了重要依据。     

Effects of Subduction of Pacific Plate on the Great Xing’an Range: Constriants from Geochronology and Geochemistry of the Shaxilate Granite Porphyry

As a widely‐developed mineral in various types of rocks, pyrite features important geological information such as temperature and pressure during its formation and evolution (An et al., 2014; An et al., 2018). It is an important geological formation for studying the origins of rocks, mineralization, and deposits (Xue et al., 2014; An et al., 2016). The study of the genesis of gold deposits is a research hotspot in current geology and mineral deposits not only because of high economic value, but also because of important practical significance (An et al., 2017; Yang et al., 2014). Shandong Zhaoyuan, as the third largest gold production area in the world, has important research significance of the origin and generation of gold‐bearing minerals (Xue et al., 2014; Wen et al., 2014). In this study, pyrite from augen granite (figure 1a), syenite (figure 1b), basite (figure 1c) and gold ore (figure 1d) at Zhaoyuan gold deposit Shandong Province, was selected as the research object. The morphological and structural micro‐fabrics were analysed by polarized light microscopy (PLM) and Raman spectroscopy to reveal the source and process of gold further.     

Comments on the paper “The nature of “Svecofennian” zircon in the Belomorian Mobile Belt and some geological implications” by A.A. Shchipanskii and A.I. Slabunov

Eclogites were relatively recently found in the Belomorian Mobile Belt (BMB) (Volodichev et al., 2004; Shchipanskii et al., 2005; Konilov et al., 2004). The very first isotopic dates (Volodichev et al., 2004; Mints et al., 2010) were obtained for these rocks in the northwestern (in the Salma and Kuru-Vaara areas) and central (Gridino area) portions of BMB and corresponded to the Archean: approximately 2.72–2.87 Ga. Because no crustal eclogites older that 2.0 Ga (Möller et al., 1995) had been known before these dates were obtained, these eclogites were regarded as unique. It is commonly believed that no crustal eclogites could be formed in the Archean because the crust was then relatively thin (Kröner, 2010), and hence, the find of crustal eclogites of Archean age in BMB called for a fundamental revision of geodynamic reconstructions of the crustal evolution and was one of the main arguments invoked to support the hypothesis that currently operating geodynamic mechanisms of plate tectonic can be extrapolated to the Early Precambrian (Rozen et al., 2008). However, these finds were practically immediately followed by serious doubts that the primary estimates of the timing of the eclogite metamorphism in the Belomorian Belt may be incorrect (Mitrofanov et al., 2009; and others).     

Diamond in Oceanic Peridotites and Chromitites: Evidence for Deep Recycled Mantle in the Global Ophiolite Record

Diamonds have been discovered in mantle peridotites and chromitites of six ophiolitic massifs along the 1300 km‐long Yarlung‐Zangbo suture (Bai et al., 1993; Yang et al., 2014; Xu et al., 2015), and in the Dongqiao and Dingqing mantle peridotites of the Bangong‐Nujiang suture in the eastern Tethyan zone (Robinson et al., 2004; Xiong et al., 2018). Recently, in‐situ diamond, coesite and other UHP mineral have also been reported in the Nidar ophiolite of the western Yarlung‐Zangbo suture (Das et al., 2015, 2017). The above‐mentioned diamond‐bearing ophiolites represent remnants of the eastern Mesozoic Tethyan oceanic lithosphere. New publications show that diamonds also occur in chromitites in the Pozanti‐Karsanti ophiolite of Turkey, and in the Mirdita ophiolite of Albania in the western Tethyan zone (Lian et al., 2017; Xiong et al., 2017; Wu et al., 2018). Similar diamonds and associated minerals have also reported from Paleozoic ophiolitic chromitites of Central Asian Orogenic Belt of China and the Ray‐Iz ophiolite in the Polar Urals, Russia (Yang et al., 2015a, b; Tian et al., 2015; Huang et al, 2015). Importantly, in‐situ diamonds have been recovered in chromitites of both the Luobusa ophiolite in Tbet and the Ray‐Iz ophiolite in Russia (Yang et al., 2014, 2015a). The extensive occurrences of such ultra‐high pressure (UHP) minerals in many ophiolites suggest formation by similar geological events in different oceans and orogenic belts of different ages. Compared to diamonds from kimberlites and UHP metamorphic belts, micro‐diamonds from ophiolites present a new occurrence of diamond that requires significantly different physical and chemical conditions of formation in Earth's mantle. The forms of chromite and qingsongites (BN) indicate that ophiolitic chromitite may form at depths of >150‐380 km or even deeper in the mantle (Yang et al., 2007; Dobrthinetskaya et al., 2009). The very light C isotope composition (δ13C ‐18 to ‐28‰) of these ophiolitic diamonds and their Mn‐bearing mineral inclusions, as well as coesite and clinopyroxene lamallae in chromite grains all indicate recycling of ancient continental or oceanic crustal materials into the deep mantle (>300 km) or down to the mantle transition zone via subduction (Yang et al., 2014, 2015a; Robinson et al., 2015; Moe et al., 2018). These new observations and new data strongly suggest that micro‐diamonds and their host podiform chromitite may have formed near the transition zone in the deep mantle, and that they were then transported upward into shallow mantle depths by convection processes. The in‐situ occurrence of micro‐diamonds has been well‐demonstrated by different groups of international researchers, along with other UHP minerals in podiform chromitites and ophiolitic peridotites clearly indicate their deep mantle origin and effectively address questions of possible contamination during sample processing and analytical work. The widespread occurrence of ophiolite‐hosted diamonds and associated UHP mineral groups suggests that they may be a common feature of in‐situ oceanic mantle. The fundamental scientific question to address here is how and where these micro‐diamonds and UHP minerals first crystallized, how they were incorporated into ophiolitic chromitites and peridotites and how they were preserved during transport to the surface. Thus, diamonds and UHP minerals in ophiolites have raised new scientific problems and opened a new window for geologists to study recycling from crust to deep mantle and back to the surface.     

瓮安生物群中海绵化石的新证据

近年来笔者依据现存的瓮安生物群中一些海绵及动物胚胎化石标本的研究，对那些可能的球形海绵体及有争议的海绵幼虫标本进行了简略的评述。本文提供的保存完好的具单轴骨针的球形海绵体化石及可能的海绵幼虫标本，对于陡山沱期出现海绵动物的推测提出了新的证据。     

由铁、镁水合氢氧化物表面吸附导致的Mo同位素分馏

Although Mo isotopes have been increasingly used as a paleoredox proxy in the study of paleo-oceanographic condition changes (Barling et al., 2001;Siebert et al., 2003, 2005,2006; Arnold et al.