中亚地区阿拉伊盆地构造地质特征与油气条件分析

阿拉伊盆地位于特提斯构造带北缘,是在古生界基底之上发展起来的山间盆地,紧邻我国西部塔里木盆地。自中生代至新生代经历了陆表海沉积期、类前陆盆地期、山间盆地发育期、拗陷期、定形期等5个演化阶段,具有海陆交互、沉积多变、多期叠加、断-拗转换的性质。生储盖匹配良好;烃源岩为古近系、白垩系和中—下侏罗统的海相与潟湖相泥岩、石灰岩和泥灰岩;主要油气储集层为碳酸盐岩裂缝性储层和砂砾岩储层;多套泥岩、膏岩和泥灰岩为区域性和局部盖层;褶皱构造发育,以背斜、断块、断鼻等构造为主。盆地具有一定的油气勘探前景。     

甘肃省阿克塞县化石沟斑岩型铜矿床特征研究

甘肃省阿克塞县化石沟铜矿是柴达木北缘缝合带上近年来发现并取得重大突破的斑岩型铜矿床。本文对矿床区域构造定位;区内近南北向弧形弯曲构造系列的形成机制及与成矿的关系;含矿浅成英云闪长斑岩的形成演化及其与成矿的关系;多种蚀变与矿化的关系以及矿床成因等方面进行了全面分析论证。这些认识有助于开拓区域上找矿的新思路。     

鄂西崆岭杂岩的组成,时代及地质演化

崆岭杂岩包括下部基底片麻岩和上部表壳岩两部分。作者采自下部的１３个斜长角闪岩样品获得ＳｍＮｄ等时线年龄３２９０±１７０Ｍａ（２σ），加入４个伴生灰色片麻岩样品后等时线年龄变为３１５０±７９Ｍａ（２σ）。采自上部的变粒岩和斜长角闪岩分别获得锆石Ｕ＿Ｐｂ一致曲线年龄为２４２７±４２Ｍａ（２σ）和２０３１±４Ｍａ（２σ）。基于这些新的数据和前人的工作成果，探讨了崆岭杂岩的形成和地质演化。     

Nature and Evolution of Pre-Neoproterozoic Continental Crust in South China: A Review and Tectonic Implications

South China as an amalgamation of the Yangtze and Cathaysia blocks is composed of Archean to Mesoproterozoic basement overlain by Neoproterozoic and younger cover. Both the constituent Yangtze and Cathaysia blocks contain well-preserved Neoproterozoic rocks that have been extensively studied in terms of the age and tectonic nature, but less is known about their earlier crustal history due to the incomplete rock record. Recent efforts in investigating the yet survived crustal nature based on isotopic and elemental signatures preserved in igneous and sedimentary rocks have steadily improved our knowledge about the pre-Neoproterozoic continental crustal evolution in South China. In this paper, we summarize the up-to-date pre-Neoproterozoic records, including petrological, geochronological, geochemical and geophysical data, across South China, and discuss its spatiotemporal patterns of the pre-Neoproterozoic crust and the relevant tectonic events. While the xenocrystic/inherited and detrital zircon records suggest widespread Archean (mainly ca. 2.5 Ga) crustal components within both the Yangtze and Cathaysia blocks, exposed Archean rocks are only limited to isolated crustal provinces in the Yangtze Block. These Archean rocks are dominated by TTGs (tonalite-trondhjemite-granodiorite) with varied ages (3.3–2.5 Ga) and zircon Hf isotopes, indicating a compositionally heterogeneous nature of the Archean Yangtze Block and, by inference, the development of multiple ancient terranes. The early Paleoproterozoic (2.4–2.2 Ga) tectonomagmatic events characterize the western Yangtze Block and are supportive of an east-west subdivision of the Yangtze basement, whereas the late Paleoproterozoic (2.1–1.7 Ga) orogeneses may have affected a larger area covering both the western and eastern parts of the Yangtze Block, and also the Cathaysia Block. The eastern Yangtze Block with generally northeastward-younging late Paleoproterozoic magmatism and metamorphism likely experienced a prolonged 2.05–1.75 Ga orogenic process welding the various Archean proto-continents, consistent with the documentation of a buried late Paleoproterozoic orogenic belt imaged by deep seismic profiling from its central part and of a slightly older ophiolitic mélange in the northern part. The Cathaysia Block was probably involved in a short-lived 1.9–1.8 Ga orogenic event. The two orogeneses overlapped in time and may have contributed to the cratonization of a possible unified South China, and are referred to be linked with the assembly of the Nuna Supercontinent. The subsequent late Paleoproterozoic to early Mesoproterozoic rift successions and intrusions (1.7–1.5 Ga) in the southwestern Yangtze Block, and the ca. 1.43 Ga rifting in Hainan Island of the Cathaysia Block could be responses to the Nuna break-up. Late Mesoproterozoic (1.2–1.0 Ga) magmatism of varied age and nature in different localities of the Yangtze Block is reflective of a complex tectonic process in the context of the assembly of the Rodinia Supercontinent. Similar-aged metamorphism (1.3–1.0 Ga) is recorded in Hainan Island, reflecting the Grenvillian continental collision during the Rodinia assembly, but further studies are necessary to better constrain the late Mesoproterozoic tectonic framework of South China.     

我国湖泊环境演变及其成因机制研究现状

湖泊沉积忠实地记录了湖泊环境变化的各类信息.不同时问尺度的湖泊环境变化分别受到构造、气候与人类活动三个方面的驱动机制的影响.影响中同湖泊环境变化的最主要的构造运动是青藏高原的隆升;气候变化的影响主要是东亚季风系统带来的一系列作用;而人类活动的影响则比较复杂,不仅有流域植被、土壤性质的改变导致输入湖泊物质的变化,也有人类活动直接改造湖泊,如围垦、封堵等.准确地分析湖泊环境变化的各种过程与规律,特别是定量刻画人与自然相互作用下的湖泊环境响应过程与驱动机理,是当今科学界的热点.     

大连市小平岛地热资源潜力研究

在明确小平岛地质背景的基础上,分析地热地质条件并判断地热资源类型,结合已有两眼井S1、S2数据资料,采用热储法对其地热资源进行潜力评估。结果表明,大连市小平岛地区为深层传导型地热资源,该区桥头组及长岭子组上部为良好地热盖层,长岭子组下部及南关岭组上部(2 100~3 300 m)为该区热储层,热储体面积为7.3 km2。单井涌水量可达600~800 m3/d,水温可达50℃~60℃,地热资源量约为4.88×1011kcal,折合标准煤为6.97×107t,可开采的地热资源量约为7.32×1010kcal。     

沼泽湿地环境演变研究回顾与展望——纪念中国科学东北地理与农业生态研究所建所50周年

沼泽湿地是地球表层功能独特的生态系统,在其形成发育、时空演化及分异等方面与其它生态系统存在明显差异。中国科学院东北地理所(原长春地理所)在沼泽湿地形成发育、时空演化研究方面有丰富的学科积累。1958年,中国科学院确定沼泽为该所的主攻方向,成为中国最早的专门性沼泽研究机构之一,至今已满50周年。50年来,几代科研人员为沼泽湿地环境演变研究工作贡献了他们的青春年华,取得了丰硕的研究成果。     

西秦岭大店沟金矿成矿流体演化及矿床成因

大店沟金矿是西秦岭成矿带近年来新发现的中型金矿床,金矿体赋存在下古生界丹凤群木其滩组绢云绿泥石英片岩中,叠加在北东东向脆韧性剪切带中的脆性构造为成矿结构面。在总结控矿地质特征的基础上,通过开展系统的流体包裹体、稳定同位素地球化学研究及成矿流体演化、矿床成因探讨,认为成矿期共分半自形黄铁矿、它形粒状黄铁矿、石英多金属硫化物和碳酸盐-黄铁矿4个成矿阶段,其中它形黄铁矿阶段和石英多金属硫化物阶段为最主要成矿阶段。流体包裹体类型以水溶液包裹体、CO₂三相包裹体和纯CO₂包裹体为主,成矿温度集中在120~256 ℃之间,成矿流体盐度为4.03%~15.27%。H-O同位素研究显示成矿热液主要为变质水混合大气降水,S同位素组成特征表明成矿物质来自深源;流体不混溶和沸腾作用是金沉淀的主要机制,矿床成因类型为造山型金矿。通过成矿结构面舒缓波状特征规律总结,判断成矿流体沿成矿结构面自南西深部向北东浅部运移、沉淀,形成分段富集矿化。     

贵州省地热深井开放式思维高质量成井综合技术

贵州省深部地热钻井开发,目前仍然是坚持只针对性钻取地质论证所确定深部目的层（主要位于2000~3500m深度之间）的传统做法。受贵州省地质结构复杂和地球物理成果解释水平双重影响,在这个深度上,钻井实际揭露的地层、水文结果往往跟论证预测情况差别巨大,因此,地热深井失败率较高。地热深井成本高昂,失败时损失严重,所以亟需研究新的成井方式。通过实践,打破传统思维藩篱,总结出“开放式思维高质量成井综合技术”,该技术是将全井作为综合系统考虑,从施工前到施工全过程,充分分析全井所有可能的有利层位,通过预留上部层位、分段固井、射孔放水、注酸洗井、压裂以及深部循环取热等多种方式进行全井地热水的综合利用,达到提高成井率的效果。研究成果对于喀斯特地区地热新能源钻探开发具有重要借鉴作用。     

塔中Ⅰ号坡折带上奥陶统礁滩的白云石化及其储集意义

塔里木盆地塔中Ⅰ号坡折带上奥陶统良里塔格组礁滩灰岩发生了少量白云石化作用。白云石化主要发育在溶洞充填的钙质渗流粉砂,泥晶生物碎屑灰岩的泥晶基质,亮晶颗粒灰岩的钙藻屑、藻砂屑、藻泥屑等三种组构中。白云石化直接贡献了平均1%的孔隙度,同时产生的白云石晶间孔为进一步溶蚀提供了通道,对有效储层的形成起到了重要作用。高镁方解石生物是白云石化所需镁离子的重要来源。这套与生物白云石化相关的礁滩储层地质预测需要深入研究钙藻、海百合等生物的古生态、岩相环境及分布。