碳酸盐岩洞穴型储层地震综合预测——以塔里木盆地古城低凸起三维区为例

塔里木盆地古城低凸起三维地震工区内的奥陶系碳酸盐岩埋藏深,非均质性强,且无钻井资料。重点对奥陶系鹰山组三段—四段白云岩的串珠状地震反射体进行地质诠释。采用均方根振幅属性预测了储层平面分布规律,应用缝洞雕刻技术预测了裂缝和串珠体发育区,运用相干、曲率属性预测了断裂、裂缝的分布,联合应用频率衰减梯度、低频能量、平均频率和吸收系数等手段进行了油气检测。通过对多种信息的综合分析,评价优选出有利勘探目标。基于上述工作部署的A井,在鹰山组三段灰质白云岩储层中获天然气勘探重大突破,证实了地震综合预测方法的有效性。     

羌塘盆地羌资5井二叠系展金组烃源岩基本特征

前人对羌塘盆地的烃源岩研究资料主要来源于中生界地表露头,少见古生界的。对羌资5井二叠系展金组烃源岩的钻井岩心研究表明,其有机碳含量高,平均值达到1.15%,属于好烃源岩。干酪根显微组分主要为Ⅲ型,其次为Ⅱ2型;有机质主要来自于海相低等水生生物,热演化已达到成熟阶段。烃源岩具较好的生气能力。认为井下烃源岩样品虽显示其处于有机质演化成熟阶段,但因受后期构造抬升的影响,推测二叠系深部未知的烃源岩可能尚处于高成熟—过成熟阶段。羌塘盆地二叠系具有较好的勘探前景,油气勘探可向深部古生界开展。     

内蒙古突泉盆地突参1井原油地球化学特征与油源分析

在内蒙古突泉盆地牤牛海坳陷南部突参1井的1684.5~1698.2m深度段侏罗系万宝组发现轻质原油,揭示了该区较好的油气勘探新领域。对该井原油和主要烃源岩分子地球化学特征、族组分稳定C同位素等进行了分析认为,该原油为轻质高蜡原油,C31升藿烷、C29甾烷异构化等成熟度参数显示该原油为成熟原油。正构烷烃呈单峰前峰型,姥鲛烷较植烷占绝对优势(Pr/Ph2.5),C29规则甾烷含量远高于C27甾烷,伽马蜡烷含量低,表明该原油生烃母质形成于以陆源高等植物为主的偏氧化沉积环境,原油来自该区侏罗系万宝组煤系泥岩。     

珠江流域碳酸盐岩与硅酸盐岩风化对大气CO_2汇的效应

对珠江流域11个测站的河水1个水文年4次取样进行水化学和同位素测试分析,揭示无论是碳酸盐岩区还是硅酸盐岩区,岩石风化均使河流的离子成分以HCO3-、Ca2+、Mg2+为主,碳酸盐岩风化溶蚀速率和由碳酸盐岩风化溶蚀引起的大气CO2消耗量分别为27.60 mm/ka和540.21x103mol/(km2·a-1),是硅酸盐岩风化速率和由硅酸盐岩风化引起的大气CO2消耗量的10.8倍和6.7倍,说明碳酸盐岩风化是流域碳汇过程及效应的主体。由于有利的水热条件和高的碳酸盐岩面积比例,珠江流域平均岩石风化速率和由岩石风化作用引起的大气CO2消耗量分别为30.15mm/ka和620.36×103mol/(km2·a-1),为全球60条河流平均值的2.6倍。     

柴北缘尕秀雅平东和红柳沟北镁铁-超镁铁质岩体锆石U-Pb年龄及其找矿意义

位于柴达木地块北缘构造带内欧龙布鲁克微陆块东缘的2个镁铁-超镁铁质岩体——含Cu-Ni的尕秀雅平东岩体和含Ti-Fe的红柳沟北岩体,前者的LA-ICP-MS锆石U-Pb年龄为408.0±1.5Ma,属早泥盆世;后者的SHRIMP锆石U-Pb年龄为418.3±2.8Ma,属晚志留世。区域地质资料研究表明,东昆仑地区、柴北缘在晚志留世—晚泥盆世处于后造山伸展阶段,尕秀雅平东岩体和红柳沟北岩体正是拉张环境下幔源岩浆活动的产物。在东昆仑地区、柴北缘发现的铜镍矿床和铜镍矿点(除夏日哈木有争议外)基本都形成于晚志留世—晚泥盆世。结合区域成矿年代学研究,认为晚志留世—晚泥盆世期间,东昆仑造山带和祁连造山带之间的柴达木地块、欧龙布鲁克微陆块,以及位于这两大造山带内部的微型古陆块区,是形成岩浆铜镍硫化物矿床和钛铁氧化物矿床的有利环境。     

内蒙古二连盆地砂岩型铀矿目的层赛汉组分段与铀矿化

近年在内蒙古二连盆地赛汉组中找到了可观的砂岩型铀矿资源。关于早白垩世赛汉组的分段没有统一的认识,严重影响了铀矿勘查工作的布置。利用石油、煤炭和核工业部门勘查钻孔岩性、测井曲线、综合编录、地震剖面等资料,结合古气候-颜色变化、沉积序列变化反映的沉积环境,将赛汉组划分为4段。赛汉组一段,主要为一套冲积扇(或扇三角洲)环境下的杂色粗碎屑岩组合。二段为一套凹陷中心灰色、黑色湖沼环境下的泥岩夹褐煤层,凹陷边缘为杂色扇三角洲粗碎屑岩,总体以黑色岩系组合为特征。三段为一套灰色、深灰色含砾粗砂岩、砂岩,侧向联通性较好的灰色岩系组合,形成于辫状河环境。四段为一套红色、黄色泥岩与砂岩互层的红色岩系或组合,沉积于曲流河环境。二连盆地马尼特坳陷中砂岩型铀矿形成于三段中,为侧向氧化成矿作用所致;而乌兰察布坳陷铀矿化定位于四段中,为垂向潜水氧化成矿作用所造成,一段和二段目前还没有找到有价值的铀矿化。     

http://www.sciencedirect.com/science/article/pii/S1674987114000413

Braid-delta depositional systems are widely developed in most continental basins in China. Research indicates that, for different types of braid delta, the facies sequence and association, which are cr...     

Kinematics of syn-tectonic unconformities and implications for the tectonic evolution of the Hala'alat Mountains at the northwestern margin of the Junggar Basin,Central Asian Orogenic Belt

The Hala’alat Mountains are located at the transition between the West Junggar and the Junggar Basin.In this area,rocks are Carboniferous,with younger strata above them that have been identified through well data and high-resolution 3D seismic profiles.Among these strata,seven unconformities are observed and distributed at the bases of:the Permian Jiamuhe Formation,the Permian Fengcheng Formation,the Triassic Baikouquan Formation,the Jurassic Badaowan Formation,the Jurassic Xishanyao Formation,the Cretaceous Tugulu Group and the Paleogene.On the basis of balanced sections,these unconformities are determined to have been formed by erosion of uplifts or rotated fault blocks primarily during the Mesozoic and Cenozoic.In conjunction with the currently understood tectonic background of the surrounding areas,the following conclusions are proposed:the unconformities at the bases of the Permian Jiamuhe and Fengcheng formations are most likely related to the subduction and closure of the Junggar Ocean during the late Carboniferous-early Permian;the unconformities at the bases of the Triassic Baikouquan and Jurassic Badaowan formations are closely related to the late Permian-Triassic Durbut sinistral slip fault;the unconformities at the bases of the middle Jurassic Xishanyao Formation and Cretaceous Tugulu Group may be related to reactivation of the Durbut dextral slip fault in the late Jurassic-early Cretaceous,and the unconformity that gives rise to the widely observed absence of the upper Cretaceous in the northern Junggar Basin may be closely related to large scale uplift.All of these geological phenomena indicate that the West Junggar was not calm in the Mesozoic and Cenozoic and that it experienced at least four periods of tectonic movement.     

长江上游安宁河流域植被生长变化对气候条件的响应

为探讨安宁河流域植被演变趋势及其与气候的相互作用,基于2001—2008年MODIS图像、降水量和气温数据,采用回归分析和相关分析等方法计算了安宁河流域降水、气温和归一化差值植被指数(normalized difference vegetation index,NDVI)在时间和空间上的变化情况,并对安宁河流域植被生长变化对气候条件的响应机制进行了探讨。结果表明:NDVI变化和气温、降水呈正相关;降水量和气温等气候因子的变动会直接反映在植被长势上,其中降水对安宁河流域植被生长的影响更为显著;植被长势与气温和降水存在一定的时间滞后性。     

Mediterranean cities under fire. A critical approach to the wildland–urban interface

Wildfires are widely reviewed as key inputs to Mediterranean ecosystems. However, research is often flawed by major biases. (1) The approach adopted by most planners focusing on forest fires dismisses the human dimension of fire as a component of agricultural production systems. (2) The Wildland–Urban Interface (WUI) concept postulates that cities and wildlands/wildfires are, and should remain, worlds apart, a statement whose truth is increasingly questioned by recent disastrous “urban wildfires”. (3) The Mediterranean Basin as a fire-prone area is all the more fantasized, as it is almost never studied as a whole.The present paper takes a critical view of city–wildland/wildfire interrelationships through a large-scale study of the Mediterranean Basin based on MODIS MCD12Q1 (Land Cover Type) and MCD45A1 (Burned Area Product) data collected between 2001 and 2013. The Mediterranean is an ideal place to investigate, as its human-dominated and urbanized landscapes are known to be extremely vulnerable to fire hazards. Data processing reveals that (wild)fires and cities maintain indissoluble ties, as if both elements could not be considered mutually exclusive on a geographical basis. Urban sprawl, reduced rural autonomies, changes in forest covers, old agricultural practices, and military conflicts provide the framework for an extended mitigation process challenging the WUI concept as a space divider.