Study on the Marine Sedimentary Environment Evolution of the Southern Laizhou Bay Under the Impact of Port Projects

The southern Laizhou Bay is mainly composed of silt-sandy coasts with diverse landforms, and its marine hydrodynamic environment is sensitive to human activities. Marine hydrodynamic and sedimentary environments of the study area have changed under the influence of large-scale port projects in recent years. In this paper, the evolution of hydrodynamic environment, deposition rate, and geochemical characteristics were studied based on sediment grain size, element analysis and ^(210)Pb dating of two cores, in order to analyze the influence of Weifang Port on marine environmental evolution, and provide theoretical and practical basis for protecting marine environment in developing marine resources reasonably. Results showed that sediments of the two cores were relatively coarser and mainly composed of silty sand. Sediments above 230 cm in core WF1 and 218 cm in core WF2 were deposited since 1855 when the Yellow River appeared to deposit its sediments within the modern active delta, and the average deposition rate was between 0.3 and 0.5 cm a^(-1). Implement of Weifang Port projects in 1997 and 2007 created great influence on the sedimentary environment evolution in the surrounding waters, and the deposition rate was significantly increased. The average annual deposition rates were 5.1 cm and 3.5 cm in WF1 and WF2 respectively between 1997 and 2007. Content of heavy metals in sediments showed no obvious change in the vertical, indicating that the heavy metals were less affected by human activity and there was no significant accumulation of such metals in the study area.

Felsic Igneous Rocks in the Hua'aobaote Pb-Zn-Ag Polymetallic Orefield,Southern Great Xing'an Range:Genesis,Metallogenetic and Tectonic Significance

The Hua’aobaote Pb-Zn-Ag Polymetallic orefield is situated in the southern section of the Great Xing’an Range(GXAR),which has experienced extensive magmatism.Since the Paleozoic,there are two stages of magmatism in Hua’aobaote orefield occurred in the Paleozoic and Mesozoic.The Mesozoic magmatism is of great significance for the PbZn-Ag Polymetallic mineralization in Hua’aobaote orefield.In this study,new geochemical data was obtained to discuss the timing and petrogenesis of the magmatic rocks and its geodynamic and metallogenic significance.Zircon U-Pb ages reveal that the felsic igneous rocks from the Hua’aobaote orefield were formed in the Early Permian(294.8±3.2 Ma)and Early Cretaceous(132.6±1.4 Ma).Geochemically,the Early Permian granodiorite porphyrite is characterized by high Sr/Y(42-63)ratios and Mg^(#)(62.24-70.74)values and low heavy rare earth element(HREE)(5.09-6.79 ppm)contents.The granodiorite porphyrite is also characterized by depleted Sr-Nd initial isotopic signatures[ε_(Nd)(t)=5.91-7.59,(^(87)Sr/^(86)Sr)i=0.7029-0.7030],exhibiting adakitic characteristics.The Early Cretaceous granite porphyry and rhyolite are A-type felsic igneous rocks,and demonstrate high SiO_(2),Na_(2)O+K_(2)O and rare earth element(REE)contents,low CaO and MgO contents,low(^(87)Sr/^(86)Sr)i ratios(0.7044-0.7058),and positive ε_(Nd)(t)values(2.57-4.65).Whole-rock Pb isotopic compositions in granodiorite porphyrite are:206Pb/204Pb=17.631-18.149,^(207)Pb/^(204)Pb=15.422-15.450,and ^(208)Pb/^(204)Pb=37.325-37.729.The granite porphyry and rhyolite have initial ^(206)Pb/^(204)Pb,^(207)Pb/^(204)Pb,and ^(208)Pb/^(204)Pb ratios of 18.106-19.309,15.489-15.539,and 37.821-38.05,respectively.Sr-Nd-Pb isotopic evidence suggests that the Early Permian granodiorite porphyrite is likely to derive from slab melts and modified by peridotitic mantle wedge in the subduction tectonic setting of the Paleo-Asian Ocean.The Early Cretaceous A-type felsic igneous rocks were derived from juvenile lower crust,accompanied by limited crustal contamination and various degree of fractional crystallisation during magma emplacement.The Early Cretaceous magmatism and related mineralization were formed in a post-orogenic tectonic setting that attributed to the closure of the Mongol-Okhotsk Ocean.Pb isotopic data for the various rock units in the study area indicate that the Mesozoic magma source contributed substantial Pb,Zn,and Ag to the Hua’aobaote deposit.

Magmatic Evolution and Mineralization Process of the Super-Large Shihuiyao Rb–Nb–Ta Deposit,Southern Great Xing'an Range,China

Rare metal ore reserves are an important strategic resource, and their metallogenic mechanism and mineralization studies have also been received widespread international attention.

Geology, Mineralization, Fluid Inclusion and Stable Isotope of the Early Cretaceous Sn and Associated Metal Deposits in the Southern Great Xing’an Range, NE China: A Review

The Southern Great Xing’an Range(SGXR) hosts a number of Early Cretaceous Sn and associated metal deposits, which can be divided into three principal types according to their geological characteristics: skarn type deposits, porphyry type deposits and hydrothermal vein type deposits. Fluid inclusion assemblages of different types of deposits are quite different, which represent the complexities of metallogenic process and formation mechanism. CH4 and CO2 have been detected in fluid inclusions from some of deposits, indicating that the ore-forming fluids are affected by materials of Permian strata. Hydrogen and oxygen isotope data from ore minerals and associated gangue minerals indicate that the initial ore fluids were dominated by magmatic waters, some of which had clearly exchanged oxygen with wall rocks during their passage through the strata. The narrow range for the δ34S values presumably reflects the corresponding uniformity of the ore forming fluids, and these δ34S values have been interpreted to reflect magmatic sources for the sulfur. The comparation between lead isotope ratios of ore minerals and different geological units’ also reveals that deeply seated magma has been a significant source of lead in the ores.

Delineation of spring capture zones in southern Great Basin,USA based on modeling results and geochemical data

The protection zones or capture zones of springs in desert environments can be hard to identify,but they are critical to spring protection.Most springs fed by regional aquifers are susceptible to contamination and groundwater development.The U.S.Environmental Protection Agency has established hydrogeologic mapping methods to delineate protection zones for springs.However,it is often difficult to determine a regional aquifer system's flow pattern with this technique alone,and the use of these methods is not conducive to efficient groundwater management.Particle tracking analysis using a well-conceptualized and calibrated numerical model for the three-dimensional groundwater flow domain feeding a given group of springs can help facilitate the identification of spring capture zone boundaries.Building upon this basis,a multifaceted approach was developed to define clear boundaries of the capture zones for the springs in the Furnace Creek,Ash Meadows,and the Muddy River areas in the southern Great Basin,USA.Capture zones were first delineated from inverse particle tracking and Hydrologic Unit 12 watersheds.Afterwards,they were adjusted based on water budgets,geology,and hydrologically significant faults.Finally,a geochemical analysis of the groundwater chemistry and isotopic data was conducted to verify the extent of each spring capture zone.This multifaceted approach adds confidence to the new delineations.

Geochronology and Geochemistry of Early Cretaceous A-type Granites in Central-Eastern Inner Mongolia,China:Implications for Late Mesozoic Tectonic Evolution of the Southern Great Xing'an Range

The southern Great Xing'an Range is the most critical Sn-polymetallic metallogenic belt in northeast China.However,the tectonic setting of the Early Cretaceous magmatic-metallogenic”flare-up“event remains uncertain.This paper presents an integrated study on the occurrence,petrology,zircon U-Pb ages,whole-rock geochemistry,and in situ zircon Hf isotopes for Wenduerchagan granites of Xi Ujimqin Banner,central-eastern Inner Mongolia.These granites consist primarily of granite porphyry(with ages of 137±1 Ma and 138±1 Ma)and(porphyritic)alkali feldspar granite(with an age of 141±2 Ma),corresponding to the early Early Cretaceous.They are A-type granites characterized by high silicon,alkali,and TFeO/MgO contents while being depleted of Ba,Nb,Ta,Sr,P,and Ti.They show right-dipping trend rare-earth element distribution characteristics with negative Eu anomalies(Eu/Eu^(*)=0.01-0.20)and weak heavy rare-earth element fractionation((Gd/Yb)_(N)=0.77-2.30).They demonstrate homogeneous zircon Hf isotopic compositions(positiveε_(Hf)(t)values from+5.3 to+7.1 and young two-stage Hf model ages of 851-742 Ma)and high zircon saturation temperatures(av.810℃).These geochemical characteristics indicate that Wenduerchagan granites originated from the partial melting of juvenile crust under high-temperature and low-pressure conditions.Wenduerchagan granites most likely formed in a post-collisional compression-extension transition regime caused by the closure of the Mongol-Okhotsk Ocean,when combined with regional geology.Such a transition regime can probably be attributed to the upwelling of the asthenospheric mantle caused by the break-off of a subducted Mongol-Okhotsk oceanic slab.Upwelling asthenospheric mantle provided sufficient energy and favorable tectonic conditions for magmatism and mineralization of the Early Cretaceous.

大兴安岭南段莲花山铜银矿床钨矿化的发现及找矿指示意义

大兴安岭成矿带是中国北方重要的铅、锌、银、铜、锡多金属成矿带,内蒙古莲花山矿床是该成矿带南段东坡的一个中型的热液脉型铜银矿床。文章在详细的研究矿床成矿系列和成矿规律的基础上,采用“全位成矿”和“缺位找矿”的思路,提出该矿床存在中高温钨多金属成矿作用的可能,并通过实施找矿勘查示范研究工作,新发现了白钨矿体,确认钨矿化的存在。该发现不仅对莲花山地区新一轮找矿突破战略行动实施提供指导,同时也对大兴安岭南段东坡钨矿潜力评价及成矿规律研究具有重要意义。

大兴安岭南段北大山岩体的年代学和地球化学:对岩石成因及成矿潜力的指示

大兴安岭南段发育包括维拉斯托、黄岗、安乐、大井、毛登和边家大院等锡多金属矿床,是我国北方最重要的锡多金属成矿带。北大山岩体是该锡多金属成矿带规模最大,出露最完全的花岗质侵入体,其北部主要为石英二长斑岩,南部为黑云母花岗岩,且南部岩相中常见电气石和绿柱石,被认为是区内锡多金属矿床的成矿母岩。然而,目前对该岩体岩石成因及其稀有金属成矿潜力的认识却存在较大争议。本文在对北大山岩体开展岩相学观察和锆石U-Pb定年的基础上,通过全岩地球化学和锆石Hf同位素分析,结合MELTS热力学模拟计算,试图阐明该岩体的成因类型、源区特征和演化过程,并讨论其成矿潜力。锆石U-Pb定年结果显示,北大山岩体北部的石英二长斑岩形成于143.4±1.3Ma,南部黑云母花岗岩形成于142.6±1.3Ma,与大兴安岭南段早白垩世锡多金属成矿年龄峰值相一致。北大山岩体中含自形富水矿物角闪石及黑云母、富碱(K_(2)O+Na_(2)O=8.58%~9.34%)、ACNK/CNK值介于0.97~1.02,P_(2)O_(5)含量低(<0.14%)且与SiO_(2)含量呈负相关,指示该岩体为高钾钙碱性I型花岗岩。岩体的锆石Hf同位素组成较为亏损(ε_(Hf)(t)值平均6.81,n=20),且全岩锆饱和温度较高(平均值为813℃),指示其为新生地壳物质高温熔融的产物。主量元素变化关系和MELTS模拟结果表明,北大山岩体为高钾钙碱性岩浆体系不同程度分离结晶的产物,其中北部石英二长斑岩样品之间结晶分异程度较低,而南部黑云母花岗岩的结晶分异程度较高。北大山岩体的形成时代、源区特征和氧化还原条件(△FMQ-2.5)与大兴安岭南段稀有金属花岗岩类似,具有一定的锡多金属成矿潜力,但其初融温度、挥发分组成(相对富B贫F)、分异演化程度(结晶分异和熔体-流体相互作用程度相对较低)明显不同于维拉斯托矿床成矿碱长花岗斑岩,不会是该矿床的成矿母岩。

大兴安岭中南段哈力黑坝岩体的年代学、地球化学及其构造拆沉作用

【研究目的】在区域地质调查基础上,本文探讨了大兴安岭中南段哈力黑坝岩体早白垩世花岗岩成岩年代、岩石成因类型、源区性质及地球动力学背景。【研究方法】本文基于显微镜、XRF和(LA-)ICP-MS等手段对哈力黑坝岩体早白垩世花岗岩进行了岩相学、锆石U-Pb年代学、地球化学及Hf同位素组成研究。【研究结果】哈力黑坝早白垩世花岗岩主要包括中细粒黑云母花岗岩和细粒斑状黑云母花岗岩,LA-ICP-MS锆石U-Pb定年结果分别为(139.1±0.7)Ma和(138.4±1.0)Ma。岩石主量元素具有高硅(74.09%~77.19%)、富碱(7.92%~8.46%),低CaO(0.35%~1.14%)和低MgO(0.15%~0.47%)的特征,属高钾钙碱性系列;其A/CNK值介于0.95~1.08,为准铝质—弱过铝质岩石。岩石相对富集轻稀土元素,(La/Yb)N=3.69~13.17,稀土配分模式图呈右倾海鸥型,具有较为明显的负铕异常(δEu=0.11~0.47)。岩石微量元素组成显示岩石富集Rb、U、Th、Zr、Hf等元素,强烈亏损Sr、Ba、Ti、P等元素。岩石具有高正的ε_(Hf)(t)值(+5.0~+11.2)和年轻的二阶段Hf模式年龄(408~731 Ma)。【结论】哈力黑坝岩体早白垩世花岗岩为铝质A型花岗岩,其源区主要为年轻地壳物质,并有老地壳物质的贡献,形成于伸展的大地构造背景,受控于岩石圈拆沉减薄过程。

内蒙古边家大院锡多金属矿床成矿岩体岩石地球化学特征及成矿潜力评价

内蒙古边家大院锡多金属矿床是大兴安岭南段多金属成矿带的代表性矿床之一,其西矿区主要发育斑岩型Sn-Cu-Mo矿体,矿体发育于石英斑岩体内。文章通过对石英斑岩开展全岩地球化学、锆石Hf同位素以及锆石微量元素地球化学分析研究,确定了该含矿岩体岩浆性质、来源及演化历史,探讨了成岩成矿关系,并进一步评估了该岩体成锡、铜矿潜力。研究表明,边家大院石英斑岩为准铝质-弱过铝质,高钾钙碱性花岗岩。稀土元素具有轻稀土元素富集、重稀土元素亏损,Eu负异常明显的特征。微量元素具有富集大离子亲石元素,亏损高场强元素的特征。结合其较低的Zr/Hf和Nb/Ta比值以及较高的Rb/Sr比值判断其经历了高分异结晶演化。根据锆石微量元素地球化学特征,确定边家大院石英斑岩源于还原性(ΔFMQ-0.15)、高温贫水(>750℃)岩浆。边家大院石英斑岩ε_(Hf)(t)为-0.86~5.99,TDM2=809~1240 Ma,为中元古代—新元古代年轻地壳部分熔融形成。根据锆石微量元素Ce^(4+)/Ce^(3+),Ce_(N)/Ce_(N)^(*),Ce/Nd和Eu_(N)/Eu_(N)^(*)指针性比值及岩浆特性判断,该石英斑岩有利于锡金属富集成矿,而成铜钼矿潜力小。

南宋临安大石佛院园林复原研究

大石佛院是南宋时期西湖最负盛名的寺庙园林之一,至今最远可追溯到公元前秦朝时,当时相传其作为秦始皇揽船石。南宋时期,大佛头作为泛舟西湖北望宝石山的重要地标,是《西湖清趣图》中突出且重要的寺庙园林,其睒电窗的窗式与朱墙壶门是南宋时期极具代表性的寺庙建筑形式。在详细考据有关大石佛院的文献古籍和历史绘画的基础上,梳理其历史沿革,并从周边环境、空间布局、建筑形制、园林活动等诸方面展开深入研究,将大石佛寺分为大石佛院、十三间楼和兜率寺三个部分,并结合《西湖清趣图》进行寺庙内外的复原想象,还原南宋时期大石佛院的园林盛景。大石佛院的复原研究为山地寺庙园林的研究提供较为重要的参考依据,同时也为南宋西湖园林研究的后续展开提供基础。

Zircon Hf Isotope Mapping for Understanding Crustal Architecture and Its Controls on Mineralization during Early Cretaceous in the Southern Great Xing'an Range,NE China

Voluminous Early Cretaceous granitoids and associated large-scale ore deposits are distributed within the southern Great Xing'an Range(SGXR),NE China.Based on previously published geochronology and zircon Hf-isotope data,Hf isotope mapping is undertaken to improve our understanding of crustal architecture and its controls on ore deposits.The ore-related Early Cretaceous granitoids were sourced predominantly from juvenile crust,with the involvement of variable proportions of ancient crustal materials.The crustal architecture,as inferred from Hf isotopic contour maps,indicates two distinct Hf isotopic domains in SGXR,including(1)a higher-ε_(Hf)(+7 to+11)juvenile crust containing minor ancient crustal material,and(2)a lower-ε_(Hf)(+2 to+6)juvenile crust containing a greater proportion of ancient crustal materials.The Hf isotopic maps identify links between crustal architecture and regional metallogeny.Copper deposits and other deposits with significant Cu production are restricted mainly to the higher-ε_(Hf)juvenile crustal regions in the northern and eastern SGXR.Deposits dominated by other metals(e.g.,Mo,Sn,W,Pb,Zn,and Ag)occur mainly in the lower-ε_(Hf)juvenile crustal regions in the southern and western SGXR.Interaction between juvenile crust-derived melts and ancient crustal components played an important role on the distribution of various ore metals.

大兴安岭南段不同退化程度草甸草原植物群落结构与物种多样性

【目的】探究大兴安岭南段草甸草原退化过程中植物群落结构及多样性的变化规律。【方法】采用样方法对大兴安岭南段不同退化程度草甸草原植被群落结构和物种组成进行调查分析,并计算重要值和多样性指数,研究其物种多样性变化。【结果】1)研究区植物共22科52属61种,植物种类主要集中在禾本科、菊科、莎草科、蔷薇科、豆科。2)随着退化程度的加剧,植物种类,群落的生物量、高度、盖度、Shannon-Wiener指数和Simpson指数显著降低。3)狼毒(Stellera chamaejasme)在群落中的重要值逐渐增加,形成狼毒型退化草地。【结论】随着大兴安岭南段草甸草原退化程度加重,群落结构趋向单一,多样性逐渐降低,草地质量急剧下降,草地生态系统原有的稳定性被破坏。

塑造“漠南股肱”——《清史稿·贻穀传》研究

《清史稿·贻穀传》是目前仅存的官方所撰贻穀个人传记。比较台北故宫博物院藏稿本与各通行版本发现,该传虽未明确记录撰者,但刊刻前仍被私自修改。该传以《清实录》为主要史源,并辅之以部分档案。该传亦有部分疏漏。同时,贻穀的历史形象受不同时代背景的影响而不断变化,从清末民初的“贪官污吏”到《清史稿》中效忠清廷的“股肱之臣”,最终在民国时期被正式确立为造福当地的“漠南股肱”。《清史稿》在贻穀历史形象演变的过程中起到重要的逆转作用。

大兴安岭南部山地植物区系多样性研究

大兴安岭南部山地坐落在蒙古高原草原区与辽河平原草原区的分水界上，北边与大兴安岭北部山地针叶林区一脉相连，南边与华北燕山山地夏绿润叶林相接．因此本区植物区系与周边植物区系发生广泛的相互交流与分化．对大兴安岭南部山地植物区系多样性及其性质进行了统计、分析，并与周边地区植物区系作了比较．该地区拥有野生维管植物１０４科，４３１属１０３１种．其植物属可划分为１５个分布区类型和３１个变型，植物种可划分为２８个分布区类型．其中温带成分数量最多，东亚成分在群落中的作用最为突出，蒙古草原成分渗透强烈，是一个植物种类相对较丰富、成分混杂、过渡性的年轻植物区系。

大兴安岭中南段二叠纪砂岩主量元素地球化学特征及物源区构造环境的判别

通过对研究区内广泛发育的二叠系哲斯组和林西组砂岩进行岩相学及主量元素地球化学研究,探讨其物源区及其古构造环境。岩相学研究结果表明:二叠系哲斯组和林西组砂岩成分成熟度较低,表现为源区相对不稳定、快速剥蚀、快速搬运的特征。A-CN-K三角图解显示砂岩母岩中斜长石含量要高于钾长石含量,指示两组砂岩物源区母岩应以具英云闪长岩和花岗闪长岩等岛弧性质的岩浆岩系列为主。主量元素判别图解揭示了物源区主要具活动大陆边缘和大陆岛弧型并含有少量被动大陆边缘物源区特点,且总体呈现出由活动大陆边缘向大陆岛弧型物源区过渡的趋势。结合前人的研究成果,推测二叠纪砂岩的物源区主要为区域内广泛分布的大石寨组火山岩及研究区北侧及北西侧的苏尼特左旗—锡林浩特—西乌旗南岩浆弧物质并含有少量来自华北板块基底的物源供给。

内蒙古双尖子山银多金属矿床侏罗纪成矿的年代学证据及其找矿意义

双尖子山银多金属矿床是近年来在大兴安岭南段发现的一超大型规模矿床,其银资源量为2.6×10~4t,锌3.3Mt,铅1.1Mt,但矿床的成矿时代目前还未得到精确的厘定,这制约了对矿床成因、区域成矿规律及找矿方向的认识。本文在详细的矿床地质特征调查基础上,识别出了与双尖子山银多金属矿床成矿有关的斑状花岗岩。该岩体内部发育浸染状方铅矿和矿化的隐爆角砾岩,岩体外接触带硅化、绿泥石化及银铅锌矿化强烈,这指示双尖子山矿床的银铅锌矿化和蚀变作用与斑状花岗岩的侵入作用密切相关。鉴于此,作者对斑状花岗岩的锆石进行了LA-MC-ICP-MS U-Pb定年,获得该岩体16颗锆石的^(206)Pb/^(238)U加权平均年龄为159.3±2.3Ma,该年龄可近似代表双尖子山矿床的成矿年龄。上述结果表明,双尖子山银多金属矿床为与晚侏罗世斑状花岗岩有关的热液脉型矿床。尽管精确的成矿年龄数据已揭示大兴安岭南段存在侏罗纪成矿事件,但大多数的观点认为早白垩世(~135Ma)是大兴安岭南段内生金属矿床成矿作用的峰期,因此忽视了侏罗纪成矿事件的重要性。鉴于双尖子山矿床银、铅和锌的资源量均已达超大型矿床规模,作者认为,大兴安岭南段侏罗纪成矿作用的强度可能并不亚于早白垩世,应在今后的找矿勘察中得到足够的重视。

大兴安岭南段内蒙古白音查干Sn多金属矿床石英斑岩的锆石U-Pb年龄、地球化学和Nd-Hf同位素特征及地质意义

白音查干矿床位于内蒙古自治区西乌珠穆沁旗,是大兴安岭南段新发现的一处大型Sn多金属矿床,也是该地区近些年来Sn矿找矿的重大突破。本文利用LA-ICP-MS锆石U-Pb法首次测得与成矿有关的石英斑岩成岩年龄为141.7±0.8Ma至140.2±1.1Ma。这一年龄与区内其他Sn多金属矿床成矿岩体的成岩年龄范围基本一致,说明大兴安岭南段与Sn成矿作用有关的花岗质岩石主要形成于早白垩世(140Ma左右)。全岩主量、微量和稀土元素地球化学特征显示,石英斑岩具有较高的SiO_2含量(70.99%~76.98%)、FeOT/(FeOT+MgO)值(0.90~0.97)、FeOT/MgO值(9.45~36.3)及10000×Ga/Al值(5.9~8.2)和较低的MgO(0.13%~0.18%)、TiO_2(0.10%~0.12%)及P2O5含量(0.02%~0.03%);稀土元素总量较低,配分模式呈轻稀土元素富集和明显负δEu异常的特点;微量元素富集Rb、U、Ta、Nd、Hf等元素,亏损Ba、K、Sr、P、Ti等元素。以上这些特征均说明,石英斑岩具备A型花岗岩的特点。微量元素、全岩Nd同位素和锆石Hf同位素结果显示,岩石具有较高的εNd(t)(+3.6^+3.8)和εHf(t)(+8.2^+11.6)值以及年轻的二阶段模式年龄(t_(NdDM2)为0.63~0.62Ga;t_(HfDM2)为0.67~0.45Ga),说明石英斑岩可能为幔源新生地壳物质部分熔融的产物,并在岩浆演化过程中经历了结晶分异作用。结合区域地质特征、成岩年代学、岩石地球化学和Nd-Hf同位素数据可知,大兴安岭南段晚中生代与Sn成矿作用有关的花岗岩以源区富含大量幔源新生地壳物质为特点,主要形成于晚中生代软流圈上涌所导致的岩石圈伸展的背景下。

深圳湾海底沉积层的研究

本文用全球定位系统（ＧＰＳ）与地脉冲剖面系统（ＧＥＯＵＩＳＥ）对深圳湾进行网格状断面勘测，经室内剖面记录解译及与钻孔记录校核，将全部剖面录入计算机，再经地理信息系统（ＧｌＳ）分析处理，得出深圳湾海底沉积层的空间分布与各种数据。

大兴安岭南段阿鲁科尔沁旗地区林西组沉积环境特征及其时限的地质意义

针对兴蒙-松嫩地区林西组沉积环境、沉积时限及古亚洲洋最终闭合时间等争议问题,通过对阿鲁科尔沁旗罕庙地区林西组的岩性、古生物、微量元素及碎屑锆石U-Pb测年等综合研究认为:林西组发育淡水双壳类和叶肢介化石,微量元素Sr/Ba值主要分布在0.05~0.18之间(平均值为0.12),B/Ga值主要分布在1.84~3.22之间(平均值为2.50),V/Cr值介于1.36~2.21之间(平均值为1.81),其沉积时期应为缺氧或贫氧的淡水湖泊环境。结合林西组砂岩碎屑锆石具有多时代物源特征、最年轻年龄为251 Ma、沉积下限年龄为晚二叠世等特征推测,古亚洲洋在研究区的最终闭合时限应为中二叠世末期,晚二叠世时期研究区即已转化为陆相沉积。