Distribution and characteristics of volcanic reservoirs in China

About forty productive oil/gas fields hosted in volcanic reservoirs have been found since 1957 in fourteen basins of China. They can be simply subdivided into two groups, the east and the west. Reservoir volcanic rocks of the east group are predominantly composed of Late Jurassic to Early Cretaceous rhyolite and Tertiary basalt, preferred being considered as rift type volcanics developed in the circum-Pacific tectonic regime. Those of the west are Permo-Carboniferous intermediate/basic volcanic rocks, being island-arc type ones developed in paleo-Asian Ocean tectonic regime.     

柴达木盆地地质灾害遥感调查

柴达木盆地是中国重要的大型盐类矿产基地之一。但随着当地气候的恶化和人类活动的影响,导致地质灾害不断加剧,给人们的生产和生活带来了直接的威胁,并严重地影响着该地区社会经济的可持续发展。利用极轨卫星具有运行周期短,覆盖范围广的优点,以ETM数据为主要遥感信息源对柴达木盆地及其周边地区的地质灾害进行遥感特征分析,可对该区地质灾害现状有宏观的了解,为柴达木盆地及其周边地区的地质灾害防治工作提供科学依据。     

深反射地震揭示喜马拉雅地区地壳上地幔的复杂结构

报告了中、美两国在喜马拉雅山区进行的第一次深反射地震试验的结果．试验剖面南起喜马拉雅山山脊南亚东县的帕里镇,向北穿过喜马拉雅山脊的荡拉,到达康马南的萨马达．剖面长约１００ｋｍ．共中心点（ＣＭＰ）叠加剖面上显示出：１．在地壳中部有一强反射带,向北缓倾斜下去,延长达１００ｋｍ以上．它可能代表了一个活动的逆冲断裂或是一条巨大的拆离带,印度地壳整体或下地壳沿此拆离层俯冲到藏南之下．２．上部地壳的反射很丰富,显示了上地壳存在着大规模的叠瓦状结构．３．下地壳的反射同相轴呈现短而有规律的分布,显示了塑性流变特征．４．在测线南部莫霍反射明显,深度达７２－７５ｋｍ．发现南部有双莫霍层的存在．５．试验中还取得莫霍层下面３２,３８,４８ｓ等双程走时的多条反射,向北倾斜,反射同相轴延续较长,信息丰富,反映了上地幔的成层结构和变形特征．这些结果对印度大陆地壳整体或其下地壳俯冲到藏南特提斯喜马拉雅地壳之下,并导致西藏南端地壳增厚的观点,给予了实质性的支持．     

基于深度学习的2D-3D地下密度异常体反演方法

地下密度异常体反演需要由二维数据反演三维结果,为了高效、高精度地反演地下异常体的位置及密度信息,本文提出2D-3D InvNet深度学习反演方法.方法的编-解码器结构,在编码阶段利用二维卷积网络结构提取地表重力异常及重力梯度异常数据信息,解码阶段利用三维卷积网络结构恢复异常体地下形态,实现了二维和三维网络结构的结合.为了精确地反演异常体密度,提出利用加权均方误差（WtdMSE）作为损失函数,同时为了更好地评估反演结果,引入核密度函数作为评价手段.与均方误差（MSE）相比,利用WtdMSE作为损失函数对异常体密度的反演结果更为准确,异常体所在区域的密度误差减少50%以上.对理论样本的反演结果表明,2D-3D InvNet在准确反演异常体地下位置的同时,也能给出准确的密度信息.应用此方法对西澳大利亚Kauring地区实测数据进行反演,我们成功获得了此区域地下异常体的密度分布.理论与实际应用结果表明,2D-3D InvNet深度学习方法稳定且具有较强的泛化性能,能在无需规定限制条件的情况下快速获得准确的反演结果.

     

盆地形成及成矿与地幔流体间的成因联系

文中共讨论以下5个问题:(1)盆地起源于幔壳溃变和膨隆,后者是地幔流体(超临界态(>375℃)HACONS流体,简称幔汁)上涌、渗入、交代、富化、致熔的产物。地幔流体造成油气盆地深部的高热流、异常超高压、伊利水云母化、硅化和地层有机碳的加氢成油作用。(2)盆地成矿可分两大阶段,先是沉积时的同生成矿;地层沉积后还有众多的后生成矿。两者组成“盆地矿套”(杜乐天,2002)。成矿无论同生还是后生,其分布均受断裂控制,都和地幔流体活动有关。(3)黑色页岩的实质是碳-硅-泥三元岩系,和热液成矿中的碳酸盐-硅质-泥质蚀变三元完全相当。此类岩系中总是有几十种亲壳亲幔亲气元素的特殊富集。奇异的是,石油、油页岩、沥青及砂岩型铀矿彼此有完全类似的继承性元素特殊富集。此等元素群不可能都是来自盆地之外蚀源区岩体的风化。研究证明,相当多的元素是地幔流体携带上来的。(4)盆地地层中广泛发育由地幔流体衍生的热液作用。(5)盆地实质上是气盆,全盆地排气。许多气田是地幔流体排气形成的。沙漠(原地型)和天然气田的共生很值得注意,两者皆源于地球强烈排气,导致地下和大气增温,过度蒸发,不易降雨,长期干旱而形成沙漠。     

塔里木板块东南缘多坝沟金矿区花岗岩类年代学、地球化学特征及找矿意义

多坝沟金矿是近年来塔里木盆地东南缘新发现的一处具有一定规模的金矿床,矿区内出露的英云闪长岩侵入闪长岩中,金矿体主要赋存在英云闪长岩体内部的构造蚀变带中。笔者对矿区闪长岩、英云闪长岩和金矿石进行了岩石学和地球化学研究,闪长岩具有埃达克型花岗岩特征,英云闪长岩具有喜马拉雅型花岗岩特征,全岩δ18OV-SMOW‰为11.0‰~13.4‰。通过金矿石的LA-ICP-MS锆石U-Pb测年,获得具有多期峰值的变质年龄,206Pb/238U年龄值在422~1 284 Ma,这组年龄显示出闪长岩形成年龄为（497±13）Ma,英云闪长岩的形成年龄为（435.9±6.6）Ma,伴随构造热液活动的年龄,成矿年龄稍晚于英云闪长岩的年龄,矿区的2期岩浆活动与塔里木东南缘-阿尔金北缘早古生代2期主要成矿阶段一致,多坝沟金矿成矿阶段主要集中在第二阶段,表明在塔里木盆地东南缘寻找与早古生代形成的埃达克型和喜马拉雅型花岗岩有关金铜矿床具有一定的潜力。     

Characteristics of China’s oil and gas pool formation in latest geological history

The structural activities took place extensively in the Asia continent during the Cenozoic era owing to the strong continent-to-continent collision and continuous compression between the India Plate and the Eurasia Plate. Huang Jiqing called such structural activities Himalayan movement. China’s sedimentary basins developed and took shape mainly during the Himalayan movement period. It is also the main period for formation and development of the oil and gas reservoirs. Of 366 large and medium-sized oil and gas fields currently found in China, 212 reservoirs were formed in the Neogene-Quaternary period. The proportion is as high as 68.2%. The oil and gas migration and accumulation in the latest geological period, which were controlled by the times, properties, styles and strength of the Himalayan movement, took place mainly in eight regions, such as the low uplift area of Bohai Sea, the onshore faulted sag area of Bohai Bay, anticlinorium zone in Daqing, the foreland fold-and-thrust belt in West China, the tilted structural zone in West China, the cratonic palaeohigh in the Tarim Basin, the zone of fault and fold belt in the East Sichuan Basin, and the biological gas zone in the East Qaidam Basin. The oil and gas pool formations in those regions have their own characteristics. With the great potential and broad prospect, those regions are the main exploration areas in China in the future.     

喀斯特高原盆地聚落空间演变——以贵州省红枫湖水系盆地为例

贵州是我国喀斯特分布最广的地区,喀斯特高原盆地是贵州主要的人口聚集地。充分认识高原盆地聚落的空间分布及其演化态势,对区域城镇规划、社会主义新农村建设及可持续发展有重要意义。以红枫湖水系盆地为例,基于GIS技术及相关软件,主要利用景观格局指数、Moran’s I系数以及居民点数据与等高线数据的空间叠置及转换技术,从水平和垂直两个维度对案例地区聚落空间分布的变化进行研究。研究表明:喀斯特高原盆地聚落的空间分布和演变具有强烈的喀斯特地域基因,在喀斯特地貌的限制下聚落总体分布分散;近年来聚落规模不断增加,在局部有一定小规模集聚并随地形限制而表现出不同的集聚形式和集聚程度;而随着数量的增多和规模的增大,聚落形态更为复杂且景观趋于破碎,空间分布更加复杂;喀斯特地貌的垂直空间特点在决定聚落的垂直分布及演变规律的同时也加剧了聚落空间分布的复杂性。     

基于TRMM数据的鄱阳湖流域降雨时空分布特征及其精度评价

基于1998-2007 年热带测雨卫星(TRMM) 3B42 V6 降雨数据分析鄱阳湖流域降雨时空分布特征, 并利用40个气象站观测日降雨数据对TRMM数据在不同子流域、不同降雨强度及不同季节里的精度进行了对比分析, 弥补了以往只评价整体精度的不足。结果显示:鄱阳湖流域北部地区修水、饶河子流域较易出现暴雨, 导致雷达信号衰减, 使TRMM对大雨强降雨的探测出现较大偏差;流域内降雨以10~50 mm为主, 其雨量占到总雨量的60%;流域降雨在年内1-3 月中旬为干旱少雨期, 3 月下旬-9 月初为湿润多雨期, 9-12 月再次进入干旱少雨期;而空间分布呈东、西部大, 中部小的格局;同时发现, 在赣南山区TRMM降雨较观测雨量低300~400 mm, 这可能受高程和坡度的影响, 使TRMM对山区降雨的探测精度也出现较大偏差。     

The Taconite Inlet Lakes Project: a systems approach to paleoclimatic reconstruction

A comprehensive study of meteorological, hydrological, limnological and sedimentological conditions in the watersheds of density-stratified (meromictic) lakes around Taconite Inlet, Northern Ellesmere Island, N.W.T., Canada was carried out from 1990–1992. Lakes C1 and C2 contain seawater trapped by isostatic uplift as the former embayments became isolated from the sea. These lakes, and Lake C3, contain varved sediments which provide an annually resolvable paleoclimatic record. By studing the major systems influencing sedimentation in one of these lakes (Lake C2) a better understanding of the climatic controls on varve formation, and hence on the paleoclimatic signal in the varved sediment record, was obtained. The varves of Lake C2 provide a proxy record of summer temperature for the region.This is the first in a series of papers published in this issue on the Taconite Inlet Lakes Project. These papers were collected by Dr R. S. Bradley.