Petrology of metamorphic rocks from the Atbashy complex,Southern Tien-Shan,Kyrgyzstan     

《地学前缘(英文版)》2018,9(6):1795-1807

The high-to ultrahigh-pressure metamorphic rocks of the Atbashy complex were petrologically investigated. The eclogites of the Choloktor Formation show a prograde evolution from epidote-blueschist facies(P = 17-21 kbar and T = 450-515 ℃) to peak eclogite-UHP conditions(P = 26-29 kbar and T = 545-615 ℃) with a subsequent epidote-amphibolite and greenschist facies overprint. The micaschists of the Choloktor Formation also show a clockwise P-T path from blueschist/epidote-blueschist facies conditions through peak eclogite facies conditions(P = 21-23 kbar and T = 530-580 ℃) to retrograde epidote-amphibolite and greenschist facies stages. A comparison of the P-T paths in the eclogites and mica-schists of Choloktor Formation reveal that they may have shared their P-T history from peak to retrograde stages. The mica-schists of the Atbashy Formation record peak metamorphism of P = 10-12 kbar and T = 515-565 ℃, which indicates that the highest grade of regional metamorphism in the Atbashy Ridge was epidote-amphibolite facies.The newly obtained P-T conditions for the mica-schists of Choloktor Formation indicate that sheets of sedimentary rocks were brought to great depths along the subduction zone and they metamorphosed under eclogite facies HP conditions. The eclogite blocks were amalgamated with mica-schists of Choloktor Formation in the eclogite facies HP conditions and together they experienced isothermal decompression to ～40 km. During this path, the eclogites and mica-schists of Choloktor Formation docked with mica-schists of Atbashy Formation at 10-12 kbar and 515-565 ℃, and from this depth(～40 km) the whole sequence was exhumed together. These new results improve our understanding of high-pressure metamorphism in subduction-related accretionary prism zones and the exhumation processes of deeply-seated rocks in the Atbashy HP-UHP complex.  相似文献   

兰州市城区地热地质条件及资源开发潜力分析   总被引：1，自引：0，他引：1       下载免费PDF全文

魏林森  张凌鹏  王婷  励丽 《中国地质调查》2018,5(2):45-50

兰州市城区地处民和—兰州坳陷盆地东端的中生代断陷盆地内。盆地中因沉积巨厚碎屑岩,加之受多期地质构造运动改造,断裂构造发育,为地热水的形成创造了条件。经勘探证实,兰州城区属中低温(60~90 ℃)沉积盆地型地热资源,分布范围受盆地南、北2条深大断裂控制,面积约530 km²。按照地质构造单元,分3个区块对地热资源潜力进行了评价,东部城区、中部城区和西部城区地热田产能分别为17.91 MW、117.46 MW和23.49 MW,达到中—大型地热田规模,显示出良好的开发利用前景。  相似文献   

基于Python实现地理国情房屋建筑专题信息提取     

秦思娴  傅晓俊  余咏胜  李甜  钟青 《测绘与空间地理信息》2015,(8)

房屋建筑是地理国情普查的重要要素之一。在实际生产工作中,由于高分辨率遥感影像受成像条件影响大以及人眼认知的局限,很难通过目视解译准确判读房屋建筑的边界、层高和密度等属性。此外,地理国情普查工作量大,重复性工作多,给地理国情普查工作带来一定困难。针对以上问题,以Arc GIS和Python为开发和应用环境,从现势性较好的1∶2 000地形图上批量提取房屋建筑专题数据,服务于地理国情普查工作。  相似文献   

面向对象的ADS80遥感影像分类在地理国情监测中的应用研究     

王安  陈容  高钊  杨超 《测绘与空间地理信息》2015,(9):69-71

ADS80影像具有红、绿、蓝、近红外等多波段影像信息。本文以ADS80影像为数据源,采用面向对象的分类方法对遥感影像进行自动提取分类研究。研究表明,采用ADS80影像与面向对象分类相结合的方法,可充分发掘影像中的形状、纹理、结构等几何特征信息,显著提高影像的分割精度,使分类后的影像具有更丰富而准确的信息,在地理国情普查及监测中具有较高的应用价值。  相似文献   

浅析安徽省地理国情普查专用符号库制作     

黄锐 《测绘与空间地理信息》2015,(9):170-171

地理国情普查是全面获取地表覆盖和基本地理国情的重要工作,是实施科学发展观的基本保障,其重要性不言而喻。本文针对地理国情普查工作制作一套完整的符号库和作业方案进行分析,便于内业解译时各种数据以所见即所得的形式直观地显示出来,提高内业数据采集和编辑工作效率的同时,更有利于外业调查方便使用。  相似文献   

地理国情在灾害应急中的专题监测研究     

陈伟  王宇龙  杜珂磊 《测绘与空间地理信息》2015,(10):82-84

地理国情为国家基本国情之一,地理国情监测应用于自然灾害的防灾减灾工作关系到群众的安全与社会的持续稳定发展。本文针对灾害的防御与应急工作,以灾害领域专题监测的内容、监测方法以及专题监测体系的构建为主要内容,进行面向服务的灾害领域专题监测的研究。  相似文献   

地理国情普查的技术流程及作业方法     

张楠楠 《测绘与空间地理信息》2015,(11):126-128

第一次全国地理国情普查是一项重大的国情国力调查,根据一年多从事地理国情生产的工作经验,并结合生产的实际情况,本文介绍了地理国情普查的技术流程及作业方法,总结了生产中的注意事项及作业经验,希望能够为地理国情普查的生产和作业提供参考和借鉴。  相似文献   

山区土地流转对缓解耕地撂荒的作用   总被引：24，自引：6，他引：18  

邵景安  张仕超  李秀彬 《地理学报》2015,(4):636-649

耕地撂荒是目前山区发展较快的一种土地利用变化,耕地流转能否缓解这一过程,促进土地资源有效配置,以避免耕地资源浪费,是一个值得探讨的课题。借助前期研究成果,使用多视角两因素散点分析和单因素相关分析方法,旨在查明山区耕地流转对缓解耕地撂荒的作用,结果表明:1在村级尺度上,样区耕地流转与耕地撂荒间呈现显著负相关关系,流转率高的村庄,撂荒率低,尤其在优等耕作条件的耕地中表现更为突出,说明耕地流转可以减少优等耕作条件的耕地撂荒;2在地块尺度上,优等耕作条件的耕地撂荒率显著低于劣等耕作条件,样区耕地的撂荒主要由Ⅳ等耕作条件的耕地所贡献;3在村级尺度上,样区耕作条件对耕地撂荒率的作用较弱,村样本间耕作条件对撂荒率差异的解释能力不强,优等耕作条件的耕地撂荒仍然存在,说明以耕地流转率代表的土地租赁市场尚不发育;4但是,样区耕地流转率高的村庄,优等耕作条件的耕地撂荒率低,说明耕地撂荒仍然受到土地租赁市场的完善程度所左右,且土地租赁市场在优化耕地资源利用方面的作用已有一定程度的显现;5进一步完善土地租赁的市场化程度,有助于减少或降低耕地撂荒现象的发生,可以避免优等耕作条件的耕地浪费。  相似文献   

On a new law of faulting along tectonic wedges: Cosserat explanation of the preferred (paleo)stress states in the Earth's crust     

《Journal of Structural Geology》2015

Cosserat extension of the Gauss stress-strain inversion method and multiple-slip method (MSM) are used to analyse 18 examples of natural wedge faulting observed in Slovenia. Based on additional numerical tests we show that kinematic incompatibility of slip along intersecting faults (wedges) has a significant effect on the state of stress in the Earth's crust. The slip direction along intersecting faults (wedges) can only be subparallel to the intersection direction between the faults. The normal stress on the wedges is then equal to the intermediate principal stress (eigenvalue) of the symmetric part of the stress tensor. This equality is very fundamental and could potentially be interpreted as a new law of faulting along tectonic wedges and non-planar faults. In the Cosserat theory of wedge faulting we also define two stress criteria, these are the weak and the strong stress conditions. The weak stress condition is related to the frictional reactivation of the wedges. It defines two limit values of the stress parameter and intermediate principal stress of the symmetric part of the stress tensor. The strong stress condition is related to the brittle faulting along tectonic wedges. It relates the angle of internal friction to the value of the stress parameter and the intermediate principal stress of the symmetric part of the stress tensor. For the value of the angle of internal friction larger than zero, the stress parameter is less than 0.5, which is in agreement with numerical and empirical observations described in this paper.  相似文献   

Uranium distribution in the lacustrine calcareous clastic-evaporite sequence in the western Qaidam Basin,and implications for U behavior in concentration of closed water     

YANG Yibo  FANG Xiaomin  LI Minghui  APPEL Erwin  ZHANG Weilin  LIU Xiaoming 《《地质学报》英文版》2014,88(Z1):168-169

正Uranium(U)provides especially useful information for reconstructing paleoredox conditions due to its unique geochemical properties and behavior in supergene environments.The proxy potential under suboxic-oxic  相似文献