新疆西准噶尔板块构造及演化

依据沉积建造、岩浆岩、蛇绿岩、变形、变质及其它板块构造特征，西准噶尔地区划分出２个一级构造单元，即西伯利亚板块、哈萨克斯坦板块；４个二级构造单元（板段）；５个三级构造单元；１４个四级构造单元。在此基础上，分６个阶段讨论了各地质时期的演化特征。西准噶尔地区的＂洋壳建造＂时限为中奥陶世－中泥盆世，东西准噶尔在晚古生代（Ｄ１－Ｄ）是相互沟通的海域。西伯利亚板块与哈萨克斯坦板块间的缝合线在达尔布特－克拉麦里。产生洋壳建造的所谓准噶尔古洋在其未闭合前尚包括了其间的一些小洋盆和岛屿。蛇绿混杂体中高压变质蓝片岩的存在，表明曾发生过古洋壳的俯冲，而蛇绿岩构造岩片间的相互叠覆，说明其侵位过程中发生过由北而南的推覆作用。残留海盆及其碰撞期后深成岩浆岩的存在，说明哈萨克斯坦板块和西伯利亚板块的最后焊接发生在残留海盆演化的晚期（闭合），据古地磁资料，两大板块在二叠纪固结并进入欧亚大陆的发展时期。     

Trace element redistribution in high-temperature deformed gabbros from East Ligurian ophiolites (Northern Apennines, Italy): constraints on the origin of syndeformation fluids

Abstract Mg-gabbros from East Ligurian ophiolites (Northern Apennines, Italy) display a high-temperature/low-pressure recrystallization localized along ductile shear zones. In deformed gabbros, the igneous diopside is recrystallized into granoblastic aggregates of neoblastic diopside and minor red-brown amphibole. The latter displays a pargasitic composition, with high amounts of Al^IV Na(A) and Ti (± 1.8, 0.7 and 0.4 atoms per formula unit, respectively). Major element composition of neoblastic minerals highlight equilibration temperature conditions in the range 800–950° C. Red-brown Ti-pargasite also occurs as a minor interstitial constituent, presumably growing from a residual trapped liquid, in the differentiated lithologies (Fe-Ti-diorites) of the plutonic ophiolitic complex. By means of ion microprobe (SIMS technique), rare earth (La, Ce, Nd, Sm, Eu, Gd, Dy, Er, Yb) and selected trace elements (Sr, Y, Cr, V, Sc, Zr, Ti) have been analysed in igneous and neoblastic diopside, as well as in Ti-pargasites. Ti-pargasites have also been analysed for F and Cl, and compared with the halogen composition of the amphiboles, mainly hornblendes to actinolites, which are related to the subsequent low-temperature brittle evolution. Neoblastic Ti-pargasite from deformed Mg-gabbros bears close compositional similarities with igneous Ti-pargasite from undeformed Fe-Ti-diorites, whereas it is geochemically distinct from the amphiboles post-dating the ductile event. In particular, Ti-pargasites have relatively high contents of F, REE, Y, Zr and Sr, which are not consistent with crystallization in the presence of seawater-derived hydrothermal fluids. High-grade recrystallization probably developed in the presence of volatile-rich igneous fluids, either trapped between the cumulus minerals or injected into the ductile shear zones from outside the local system. An alternative hypothesis comprises the absence of fluid phase and the development of ductile shear zones in Ti-pargasite-rich layers. The petrological features of deformed gabbros recovered from present-day slow-spreading ridges and fracture zones bear close similarities with the investigated ophiolitic metagabbros. In East Ligurian ophiolites, high-grade ductile shear zones have been related to the initial stages of the uplift of the gabbro-peridotite complex to the sea-floor.     

北准噶尔洪古勒楞蛇绿岩研究的新进展

通过对洪古勒楞东段蛇绿岩的研究，基本搞清了蛇绿者组合特征及其形成时代，首次指出该区在晚震旦世为广阔大洋环境，为研究准噶尔的大地构造演化提供了证据。依据蛇绿岩与围岩的接触关系，指出了其构造侵位时间为奥陶纪末，而与泥盆系则为断层接触。通过Ｓｍ－Ｎｄ等时线法测年结果确定蛇绿岩形成于６２６±２５Ｍａ。从稀土元素、岩石化学和εＮｄ（Ｔ）＝十８．４等综合分析，蛇绿岩来自亏损地幔岩浆，纯属洋中脊产物。     

西藏多龙矿床技术经济评价指标框架

班公湖一怒江成矿带是近年来在西藏地区发现的继玉龙铜矿带和冈底斯铜矿带之后的又一成矿带,以多龙矿集区为典型代表,目前已在区内发现拿顿、波龙、多不杂、拿若、色那、铁格龙、尕尔勤等矿床,已经探明的铜达到18.0 Mt,金300 t,其中多不杂和波龙的铜金属量达到7.047 Mt,金达到168.8 t。多龙矿床已经成为我国最大的铜矿床,并具有巨大的找矿潜力（符家骏等,2014;陈红旗等,2015）。     

Southern borderland of Triassic Laurasia in north-east Iran

Results obtained by Iranian and European geoscientists in the critical area to the north-east of the North Iran Suture east of Mashhad are desribed and discussed. A slightly metamorphosed ophiolite belt, outcropping as the south easterly continuation of the previously known ophiolites of Mashhad along the north eastern perimeter of the Fariman-Torbat-e-Jam depression, proved to be either the remnant of a Permian ocean floor or more likely the remnant of a narrow ocean trough. There is as yet no proof of a Triassic age for this ophiolitic belt. To the north of this ophiolitic belt an epicontinental Triassic sequence is exposed at the southern edge of Laurasia in the erosional Window of Aghdarband. This is the result of intermittent sedimentation in a pull-apart basin along sinistral strike-slip faults. The Triassic of Aghdarband has much in common with other deposits of the Triassic Tethys; however, it shows a few unique features, e.g. the Early AnisianNicomedites fauna of a palaeobiogeographic North Tethyan Subprovince, or volcanogenic sedimentation during the late Anisian and the entire Ladinian.Permian ophiolites outcropping at the south-west corner of the Aghdarband erosional Window are transgressively overlain by basal conglomerats of this Triassic sequence. Hence the existence of a Triassic ocean south of Laurasia is very unlikely. This is an agreement with paleomagnetic data which suggest that the Central Iranian microcontinent was in direct contact with Laurasia during Triassic times. These palaeomagnetic data also suggest a clockwise rotation of the Central East Iran microplate during Triassic times (contrary to the anticlockwise rotation of this microplate in post-Triassic times). The sinistral strike-slip faulting and compression from the south-west which controls the structure of the Triassic may be derivative sequels to this clockwise rotation. All Eo-Cimmerian deformations of the Triassic rocks (e.g. folding, thrust faulting, strike-slip faulting) had stopped by Rhaetian times.     

蛇绿岩套中超基性岩体的岩石组合:蛇纹岩、异剥钙榴岩和蛇绿碳酸岩——以西阿尔卑斯Zermatt-Saas蛇绿岩为例

蛇纹岩、异剥钙榴岩和蛇绿碳酸岩是蛇绿岩套中超基性单元特有的3类岩石组合,该套岩石组合的形成过程复杂,经历了从地幔岩浆结晶分异、洋脊变质作用改造和俯冲-仰冲构造过程,记录了从地幔岩浆侵位到造山带形成、演化的全程信息。蛇纹岩由方辉橄榄岩、二辉橄榄岩和纯橄岩通过水化和氧化过程而形成;异剥钙榴岩由含水石榴石、符山石、绿帘石族矿物、透辉石和绿泥石等含水和含钙的硅酸盐矿物组成,是由基性岩经历钙交代和水化作用而形成;蛇绿碳酸岩则由高度破碎变形的蛇纹岩角砾和碳酸岩基质(方解石、白云石或菱镁矿)共同组成,碳酸钙主要来自海水参与蛇纹岩化过程产生的富钙热液。阿尔卑斯西部的Zermatt-Saas蛇绿岩体中这3种岩石的组合研究表明:蛇纹岩化过程发生在大洋变质时期,超基性岩体在海水的作用下形成蛇纹岩。蛇纹岩化过程中释放出主要来自斜方辉石和单斜辉石的钙,与水共同作用交代超基性岩体中的基性岩脉,从而形成异剥钙榴岩。蛇绿碳酸岩形成于俯冲变质之前或俯冲变质的早期。这3类岩石一经形成,都经历了其后的叠加变质作用,进而表明Zermatt-Saas蛇绿岩经历了大洋变质、与俯冲、折返和抬升有关的高压变质和区域变质、绿片岩相变质和晚期热液变质作用的pT轨迹演化,代表着西阿尔卑斯从洋脊变质作用到俯?     

Geochemistry and geochronology of the Neoproterozoic Pan-African Transcaucasian Massif (Republic of Georgia) and implications for island arc evolution of the late Precambrian Arabian–Nubian Shield

The Transcaucasian Massif (TCM) in the Republic of Georgia includes Neoproterozoic–Early Cambrian ophiolites and magmatic arc assemblages that are reminiscent of the coeval island arc terranes in the Arabian–Nubian Shield (ANS) and provides essential evidence for Pan-African crustal evolution in Western Gondwana. The metabasite–plagiogneiss–migmatite association in the Oldest Basement Unit (OBU) of TCM represents a Neoproterozoic oceanic lithosphere intruded by gabbro–diorite–quartz diorite plutons of the Gray Granite Basement Complex (GGBC) that constitute the plutonic foundation of an island arc terrane. The Tectonic Mélange Zone (TMZ) within the Middle-Late Carboniferous Microcline Granite Basement Complex includes thrust sheets composed of various lithologies derived from this arc-ophiolite assemblage. The serpentinized peridotites in the OBU and the TMZ have geochemical features and primary spinel composition (0.35) typical of mid-ocean ridge (MOR)-type, cpx-bearing spinel harzburgites. The metabasic rocks from these two tectonic units are characterized by low-K, moderate-to high-Ti, olivine-hypersthene-normative, tholeiitic basalts representing N-MORB to transitional to E-MORB series. The analyzed peridotites and volcanic rocks display a typical melt-residua genetic relationship of MOR-type oceanic lithosphere. The whole-rock Sm–Nd isotopic data from these metabasic rocks define a regression line corresponding to a maximum age limit of 804 ± 100 Ma and εNd_int = 7.37 ± 0.55. Mafic to intermediate plutonic rocks of GGBC show tholeiitic to calc-alkaline evolutionary trends with LILE and LREE enrichment patterns, Y and HREE depletion, and moderately negative anomalies of Ta, Nb, and Ti, characteristic of suprasubduction zone originated magmas. U–Pb zircon dates, Rb–Sr whole-rock isochron, and Sm–Nd mineral isochron ages of these plutonic rocks range between  750 Ma and 540 Ma, constraining the timing of island arc construction as the Neoproterozoic–Early Cambrian. The Nd and Sr isotopic ratios and the model and emplacement ages of massive quartz diorites in GGBC suggest that pre-Pan African continental crust was involved in the evolution of the island arc terrane. This in turn indicates that the ANS may not be made entirely of juvenile continental crust of Neoproterozoic age. Following its separation from ANS in the Early Paleozoic, TCM underwent a period of extensive crustal growth during 330–280 Ma through the emplacement of microcline granite plutons as part of a magmatic arc system above a Paleo-Tethyan subduction zone dipping beneath the southern margin of Eurasia. TCM and other peri-Gondwanan terranes exposed in a series of basement culminations within the Alpine orogenic belt provide essential information on the Pan-African history of Gondwana and the rift-drift stages of the tectonic evolution of Paleo-Tethys as a back-arc basin between Gondwana and Eurasia.     

西藏多龙尕尔勤——一个遭受过剥蚀的浅成低温热液金矿床

西藏具有形成巨型斑岩铜成矿系统的地质背景。浅成低温热液型金矿常发育于斑岩铜成矿系统上部,极具经济价值,但由于形成深度较浅,易于剥蚀,目前西藏地区尚未发现独立的浅成低温热液型金矿床。多龙超大型铜金矿集区位于西藏班公湖-怒江成矿带西段,产出有大型-超大型斑岩-浅成低温热液型铜金矿床,而是否存在独立的浅成低温热液型金矿,既是重大科学问题,也是勘查的重点方向。文章运用超景深高分辨数码显微镜、扫描电镜及电子探针等手段,系统研究了多龙矿集区尕尔勤矿区内的残坡积物和外围水系沉积物中746颗砂金的大小、形貌、核部元素及不透明矿物包体特征,发现尕尔勤矿区内广泛分布的砂金不是表生环境下生物化学或化学成因金,而是尕尔勤产出的金矿(化)体剥蚀的产物。砂金普遍含有较高的w(Bi)、极低的w(Cu),部分含有高的w(Hg)、w(Te);砂金w(Ag)变化较大（0.05%～40.21%）;金成色变化范围较大（588～999）;砂金富含Bi-Pb-Te-S系列矿物包体等,显示尕尔勤矿区可能存在一个遭受过剥蚀的浅成低温热液金矿床。     

Mineralogy,geochemistry and geotectonic significance of harzburgites from the southern Dramala upper mantle suite,Pindos ophiolite complex,NW Greece

The Dramala massif, located in the Dinarides–Hellenides orogenic belt, forms the mantle section of the Neotethyan Pindos ophiolite complex in NW continental Greece. Its southern domain is comprised mainly of voluminous harzburgite masses with variable clinopyroxene and olivine modal abundances, ranging from clinopyroxene‐bearing to typical and olivine‐rich harzburgites. The harzburgite varieties are characterized by elevated Cr# [Cr/(Cr + Al)] in Cr‐spinel (0.43–0.79), high forsterite (Fo) content in olivine (0.90–0.93), low Al₂O₃ content in clinopyroxene (≤1.77 wt.%) and poor whole‐rock abundances of Al₂O₃ (≤0.68 wt.%), CaO (≤0.68 wt.%), Sc (≤11 ppm) and REE, which are indicative of their refractory nature. In terms of fO₂ values, the southern Pindos harzburgites plot between the FMQ‐2 (Fayalite–Magnetite–Quartz) and FMQ + 2 buffers. Simple batch and fractional melting models are not sufficient to explain their depleted composition. Their Ni/Yb ratios vs. Yb bulk‐rock abundances can be reproduced by up to 22–31% closed‐system non‐modal dynamic melting of an assumed spinel‐bearing lherzolite source. Cr‐spinel chemistry data suggest that the southern Dramala harzburgites were formed in an oceanic centre and then were reworked in the mantle wedge above a subducted slab. Combined petrographic and compositional data indicate that the studied harzburgites interacted with arc‐derived tholeiitic melts. This interaction resulted in substantial olivine and minor Cr‐spinel addition to the studied harzburgites, thus enhancing their refractoriness. Cryptic metasomatism was plausibly responsible for the demolition of any strong geochemical signatures suggestive of a previous melting event in a spreading centre. Comparable observations from the neighbouring Vourinos suite imply that the southern Dramala harzburgites probably represent an arc/fore‐arc mantle region within the mutual Pindos–Vourinos, Mesohellenic lithospheric mantle. Copyright © 2014 John Wiley & Sons, Ltd.     

西藏多龙矿集区尕尔勤铜金矿砂金矿物学特征及意义

正多龙矿集区位于西藏羌塘地体南缘,班公湖—怒江成矿带西段,是我国藏西北地区最重要的铜多金属资源基地之一。区内发育有铁格隆南、多不杂、波龙、拿若、拿厅、色那、赛角、尕尔勤、地堡那木岗等众多斑岩—浅成低温热液型矿床,累计铜资源量超过2000×10~4 t,伴生金资源量超500 t,