川中-川南过渡带雷口坡组沉积相特征

根据四川盆地中三叠统雷口坡组的区域背景资料,对川中—川南过渡带雷口坡组的沉积特征进行研究,认为雷口坡组属于陆表海型局限～蒸发海台地相沉积,可进一步划分为粒屑滩、半局限泻湖、局限泻湖、蒸发泻湖等4种亚相及10余种微相,其中,雷一^1亚段的颗粒滩亚相是本区雷口坡组主要的有利储集相带。通过对重点层段雷口坡组雷一^1亚段的沉积微相平面展布特征分析,建立了该亚段颗粒云岩沉积期的陆表海碳酸盐岩台地相的沉积演化模式,并认识到本区雷口坡组沉积相受古气候、相对海平面变化、构造活动以及继承性古隆起的影响,在纵向上具有继承性,平面上分布稳定。     

海州式磷矿床沉积环境探析

海州式磷矿床属沉积变质矿床，中元古代海州群锦屏组、肥东群双山组、宿松群柳坪组和虎踏石组及红安群七角山组等为赋矿岩层。在沉积阶段，磷块岩的沉积严格受岩相吉地理控制。磷块岩沉积在浅海相区台地相边缘的浅滩之中。     

鄂尔多斯盆地三道坎组混合沉积的生物扰动构造与古地理

首次在鄂尔多斯盆地西北缘桌子山地区下奥陶统三道坎组发现遗迹化石，其中绝大部分为无法鉴定遗迹属种的生物扰动构造。该组属碳酸盐岩与陆源碎屑岩互层的混合沉积，按岩性及韵律性将其分为5段，分析概括了生物扰动构造的分布、特征及形成的沉积环境。本组沉积期出现的古地理环境主要包括前滨沙滩及沙坝、云坪及含沙云坪、局限台地潮下低能、台地粒屑滩(介壳滩)和开阔台地潮下带。采用沉积学与实体化石及生物扰动构造半定量分析相结合的研究方法，阐述了各古地理单元的特征与各段沉积期的古地理环境，认为：本组沉积早期先后以含沙云坪环境、局限台地潮下低能环境为主，中、晚期则开阔台地潮下带环境频繁出现并时而占优势，反映了海平面上升的总体趋势；同时在海进的背景下，前滨沙滩、沙坝与云坪、含沙云坪或开阔台地潮下带等环境的交互出现，则反映了阿雷尼格中期本区是接近古陆的，随着相邻古陆的周期性抬升或海平面的周期性上升，出现了海陆争夺、频繁的海水进退的古地理变化，从而混合沉积发育。直形壳鹦鹉螺类化石产出状态的研究等表明三道坎组古流向是自北而南的。据岩性和古生物化石分析，本组沉积期气候干热，桌子山地区应归属早奥陶世华北亚热带干旱气候区。     

江绍断裂两侧早元古代变质基底特征及形成的构造环境

江绍断裂东侧出露的早元古代变质基底以一套遭受中压型角闪岩相区域热流变质作用改造的黑云斜长变粒岩、云母石英片岩为主，夹少量斜长角闪岩和大理岩，已遭受４期构造变形作用改造，从原岩建造和主要岩类地球化学特点推测它可能形成于大陆或大陆边缘类似于内硅铝盆地环境。江绍断裂西侧早元古代变质基底则以星子杂岩为代表，由变粒岩、浅粒岩、（十字一石榴）云母片岩和少量斜长角闪岩组成，已遭受中压型高绿片岩相一低角闪岩相区域热流变质作用改造，推测其形成于活动性较强大陆一大陆边缘环境。江绍断裂两侧早元古代变质基底在原岩建造、变质一变形作用等特征上存在明显差异，因此华夏地块和扬子地块在早元古代可能是两个地块。     

深海钻探与南海

本文从南海北部陆缘，南部陆缘和南海中央海盆的地质构造与地球物理主要特下及尚未解决的重要地质问题来阐述在南海进行深海钻探的意义。南海北部陆缘是离散型大陆边缘，在陆壳与洋壳之间的磁静区是两者的过渡区。对它的研究直接关系到南海的形成演化与沉积盆地的成因，深海钻探需要解决的主要问题是了解磁静区基底下的物质是减薄的过渡壳还是古洋壳。地海南部南缘与北部陆缘不同，是聚敛型大陆边缘，它的构造与地球物理场特征与北部     

海平面变化成因及其盆地响应

海平面及海平面变化研究成果可概括为10个方面,但应将海平面与海平面变化,海平面升降与振荡、波动,全球与相对、高频、复合海平面、T-R旋回与海平面变化等的概念理清,限制其概念的外延和内涵及其相互之间的关系。对利用沉积记录来研究海平面变化的重视程度很高,但对海平面变化对沉积盆地的影响注意甚少。建议关注海平面升降变化对盆地充填物的作用,对沉积型矿床的控制和对大陆边缘地壳变形的反弹作用过程的研究及定量模拟是一个重要方向,它可能为大陆边缘动力学研究提供一方面的思路。     

绿洲边缘内外大气中水汽影响辐射传输分析

水汽是大气中影响辐射传输的重要因子之一,实验观测表明在绿洲内外近地层大气中水汽含量存在一定的差异,因此绿洲边缘内外在气中辐射传输特征也不同。本文通过应用ＭＯＤＴＲＡＮ辐射模式和“干旱环境综合研究计划９５”（简称ＡＥＣＭＰ９５）野外实验近地面观测资料,分析了局地大气对达到地面辐射通量密度或辐射率、透射的影响,并与地面观测结果进行了比较,同时对绿洲边缘内外太阳辐射近红外１．５５￣１．７μｍ带和大气窗区     

Geochemical and isotopic characteristics of volcanic rocks from the northern East China Sea shelf margin and the Okinawa Trough

Volcanic rocks both from the northern East China Sea (NECS) shelf margin and the northern Okinawa Trough are subalkaline less aluminous,and lower in High Field Strength Elements (HFSE).These rocks are higher in Large Ion Lithophile Elements (LILE),thorium and uranium contents,positive lead anomalies,negative Nb-Ta anomalies,and enrichment in Light Rare Earth Elements (LREE).Basalts from the NECS shelf margin are akin to Indian Ocean Mid-Ocean Ridge Basalt (MORB),and rhyolites from the northern Okinawa Trough have the highest 207 Pb/ 204 Pb and 208 Pb/ 204 Pb ratios.The NECS shelf margin basalts have lower 87 Sr/ 86 Sr ratios,ε N d and σ 18 O than the northern Okinawa Trough silicic rocks.According to 40 K– 40 Ar isotopic ages of basalts from the NECS shelf margin,rifting of the Okinawa Trough may have been active since at least 3.65–3.86 Ma.The origin of the NECS shelf margin basalt can be explained by the interaction of melt derived from Indian Ocean MORB-like mantle with enriched subcontinental lithosphere.The basalts from both sides of the Okinawa Trough may have a similar origin during the initial rifting of the Okinawa Trough,and the formation of basaltic magmas closely relates to the thinning of continental crust.The source of the formation of the northern Okinawa Trough silicic rocks was different from that of the middle Okinawa Trough,which could have been generated by the interaction of basaltic melt with an enriched crustal component.From the Ryukyu island arc to East China,the Cenozoic basalts have apparently increasing trends of MgO contents and ratios of LREE to Heavy Rare Earth Elements (HREE),suggesting that the trace element variabilities of basalts may have been influenced by the subduction of the Philippine Sea plate,and that the effects of subduction of the Philippine Sea plate on the chemical composition of basaltic melts have had a decreasing effect from the Ryukyu island arc to East China.     

Depositional environment in the southern Ulleung Basin, East Sea (Sea of Japan), during the last 48 000 years

The present study is based on the sedimentological data from a piston core KCES1 off the southern Ulleung Basin margin, the East Sea (Sea of Japan). The data include sediment color (L^*), X-ray radiographs, grain size distribution and AMS¹⁴C date. Four kinds of sediments (homogeneous, laminated, crudely laminated and hybrid sediments) are identified according to the characters of the sedimentary structures that were considered to reflect changes in bottom-water oxygenation. Alternations of dark laminated/crudely laminated sediments and light homogeneous sediments represent millennial-scale variations that are possibly associated with the high-resolution changes in the East Asian monsoon (EAM). The relative contributions of the East China Sea Coastal Water (ECSCW) and the Tsushima Warm Current (TWC) were likely the main reasons for the repetition of the anoxic and oxic depositional conditions in the East Sea since the last 48 ka BP. During the interstadial, the strengthen summer EAM was attributed to the expansion of the ECSCW because of more humid climate in central Asia, and then more strongly low-salinity, nutrient-enriched water was introduced into the East Sea. The ventilation of deep water was restricted and therefore the dark laminated layer deposited under the anoxic bottom water condition. During the lowest stand of sea level in the last glacial maximum (LGM), the isolated East Sea dominated by stratiˉed water masses and the euxinic depositional environment formed. The homogenous sediments have been predominating since 17.5 ka BP indicating that the TWC has intruded into the East Sea gradually with the stepwise rise of sea level and the bottom water oxygen level was high. During the late Younger Dryas (YD) period, the last dark laminated layer deposited because the ventilation of bottom water was restricted by stronger summer EAM. The TWC strengthened and the bottom water became oxic again from 10.5 ka BP.