克拉美丽山南缘西段盆山耦合机制          下载免费PDF全文

易泽军李涤  连奕驰 《地质科学》2018,(1):169-184

克拉美丽山位于准噶尔盆地东部,晚古生代克拉美丽洋盆向北俯冲消亡,西伯利亚板块与准噶尔地块在该地区发生碰撞造山。目前,就石炭纪之后克拉美丽山的构造活动存在持续挤压、拉分、伸展、挤压-伸展转换多种观点,构造样式也各不相同。本文应用断层相关褶皱理论,从盆山过渡带现今构造样式入手来探讨克拉美丽山南缘西段盆山耦合机制。研究结果表明,克拉美丽山西段在石炭纪之后经历了中二叠世早期、早三叠世早期、晚三叠世末期、晚侏罗世-早白垩世、晚白垩世早期和古新世末期6 次构造隆升。前4 期相对稳定沉积,晚白垩世早期,晚古生代地层沿着下二叠统底部的泥岩层滑脱面以叠瓦状构造楔样式向南楔入,构造缩短量大于15 km,现今盆山构造样式初步形成。始新世构造楔遭受后期突破断层改造。始新世后,克拉美丽山大规模的构造活动基本停止,地层遭受剥蚀最终形成现今地质结构。  相似文献   

中国帕米尔地区黄土上部色度变化特征及古气候意义   总被引：4，自引：1，他引：3  

陈杰  杨太保  曾彪  何毅  冀琴 《沉积学报》2018,36(2):333-342

以中国境内帕米尔黄土-古土壤序列为研究对象,对剖面上部进行土壤色度指标与其他常用气候替代指标（如磁化率、碳酸盐和有机碳）对比研究后发现:在帕米尔黄土沉积期间,亮度L*很大程度上受控于颜色分量a*和b*,进而可能与影响a*、b*的物质相对含量有关。红度a*在整个黄土-古土壤剖面中变化特征明显,与磁化率呈明显的负相关关系,可能与土壤中铁氧化物的种类和含量关系密切。由于a*和b*具有较高的相关性,认为它们具有较为一致的致色物质,可能受控于相似的气候因子。色度a*、b*和亮度L*的变化表明其可以作为帕米尔地区良好的气候代用指标,结合磁化率共同反映该地区的古气候变化过程。  相似文献   

Tracing submarine groundwater discharge flux in Tolo Harbor,Hong Kong (China)     

Yi Liu  Jiu Jimmy Jiao  Ho Kwan Cheng 《Hydrogeology Journal》2018,26(6):1857-1873

Submarine groundwater discharge (SGD) is an important pathway for groundwater and associated chemicals to discharge to the sea. Groundwater levels monitored along a transect perpendicular to the shoreline are used to calculate SGD flux from the nearshore aquifer to Tolo Harbor, Hong Kong (China). The calculated SGD flux—recharge/discharge measured with Darcy’s Law methods—agrees well with estimates based on geo-tracer techniques and seepage meter in Tolo Harbor during previous studies. The estimated freshwater SGD is 1.69–2.0 m²/d at the study site and 0.3?±?0.04 cm/d for the whole of Tolo Harbor, which is comparable to the river discharge (0.25?±?0.07 cm/d) and precipitation (0.45?±?0.15 cm/d). The tide-driven SGD in the intertidal zone is 13.98–17.59 m²/d at the study site and 2.42?±?0.56 cm/d for the whole of Tolo Harbor. The SGD occurring in the subtidal zone and the bottom of Tolo Harbor is 3.12?±?4.63 cm/d. Fresh SGD accounts for ~5% of the total SGD, while the rest (~95%) is contributed by saline SGD driven by various forces. About 96% of the tide-driven SGD in the intertidal zone occurs in the ebbing tide period because the head difference between the groundwater level and sea level is great during this period. Tide-driven SGD in the spring tide is ~1.2 times that during neap tide. The tidal fluctuation amplitude and tide-driven SGD in the intertidal zone are positively correlated to each other; thus, a spring neap variation of the tide-driven SGD is observed.  相似文献   

安徽凤阳山区石英岩矿成矿规律分析     

殷张明  徐学军  胡殿坤  胡甦  王依 《安徽地质》2018,28(1):30-32

凤阳山区石英岩矿床成因类型主要有沉积变质型和沉积型两种,均属层控性矿床。其中沉积变质型石英岩矿是本区主要类型矿床,赋存构造体系为老青山单斜,控矿层位为凤阳群白云山组地层,矿石类型主要为石英岩,其次是石英砂岩、含白云母石英岩等;沉积型石英岩矿赋存构造体系为雷家户-宋集单斜,控矿层位为八公山群伍山组,矿石类型主要为石英砂岩。区内发育的褶皱构造为石英岩矿体提供了广阔的赋存空间,而断裂构造的发育却对矿体分布的连续性造成了不同程度的破坏,对石英岩矿石质量也有一定的影响。  相似文献   

南极南设得兰群岛海域地质新进展:“海洋六号”南极科考初步成果     

何高文  付少英  邓希光  赵庆献  王力峰  王海峰  关晓春  刘胜旋  庞云天  陈玺  柴祎  罗贤虎  朱本铎  朱振华  李强  苏丕波  何赵  吴聪  黄宁  何发光  蓝明华 《地球学报》2018,39(6):643-656

2016—2017年跨年度执行的中国第33次南极科考“海洋六号”航次, 首次获取了南极半岛南设得兰群岛北部海域、布兰斯菲尔德海峡以及欺骗岛三个区域的17 850 km2范围内多波束全覆盖高精度水深数据, 地形分辨率高于目前公开的国际数据。多道地震结果显示调查区多处存在天然气水合物地球物理标志BSR。地热测量热流值表明南设得兰群岛以北热流值与全球海洋热流值数据吻合, 不存在明显异常, 群岛以南热流值数据偏高。沉积物样品为典型的冰海沉积物, 在南设得兰群岛与南设得兰海沟之间, 沉积物以粉砂-砂为主, 夹杂砾石, 随水深增加, 沉积物粒径变细; 而在布兰斯菲尔德海区表层沉积物分布具有不对称性, 海槽南部陆架-上陆坡以及海槽东北和相邻陆架, 沉积物以砾石、砂质为主; 海槽和下陆坡为粉砂质硅质软泥。沉积物顶空气样品现场测试结果表明, 表层沉积物50 cm左右深度内的甲烷含量没有明显的差异性, 但在岛坡深水区两个测站甲烷含量在270 cm 左右深度时都存在局部高异常, 且两者总甲烷含量的变化趋势有一定的相似性, 可能与水合物分解迁移有关。  相似文献   

内蒙古西乌旗罕乌拉地区下二叠统寿山沟组碎屑锆石LA-ICP-MS U-Pb年龄及其地质意义   总被引：2，自引：2，他引：0  

张晓飞  王必任  张华川  周毅  冯俊岭  曹军  滕超  刘俊来 《地质通报》2018,37(5):863-880

中亚造山带南缘二叠纪的构造背景一直存在争议。以内蒙古西乌旗罕乌拉地区发育的寿山沟组为研究对象,开展了野外地质、岩石学、碎屑锆石LA-ICP-MS U-Pb年龄研究。2个样品锆石阴极发光图像和Th/U值指示,锆石为岩浆成因锆石。103颗碎屑锆石年龄测试结果显示,年龄信息可划分为5组:285~328Ma,峰期年龄302Ma;338~361Ma;455~490Ma;757Ma;1278Ma、2380Ma。最年轻的年龄为285Ma,结合侵入其中的花岗岩同位素年龄,指示西乌旗罕乌拉地区寿山沟组沉积时限介于285~280Ma之间,主体沉积时代应为早二叠世Sakmarian期—Artinskian期。寿山沟组碎屑锆石反映出近源、快速沉积的特点,沉积物源中含有较多的火山碎屑物,可能代表弧后盆地沉积,为早二叠世古亚洲洋闭合前洋壳俯冲消减作用的沉积响应。结合区域资料,寿山沟组碎屑锆石的年龄对应于东北地区的变质基底及其后的构造岩浆事件,物源区物质主要来自于苏尼特左旗—锡林浩特—西乌旗一带早石炭世末—晚石炭世岩浆弧及贺根山—东乌旗一带,并进一步限制了华北与西伯利亚两大板块的缝合线应位于寿山沟组发育地区的南部,即索伦缝合带,拼合时代最可能为晚二叠世—早三叠世。  相似文献   

Longitudinal genetic analysis of growth-related traits in red swamp crayfish Procambarus clarkii (Girard)     

Wang  Hui  Zhang  Yi  Chang  Guoliang  Wu  Nan  Xu  Zhiqiang  Tang  Jianqing 《中国海洋湖沼学报》2022,40(2):775-785

Journal of Oceanology and Limnology - The red swamp crayfish, Procambarus clarkii, is an economically important species especially in China. Their exoskeleton places serious constraints on growth...  相似文献   

2020-07-12河北唐山M_S5.1地震震源参数及发震构造分析     

周依  王想  孙丽娜 《大地测量与地球动力学》2022,42(2):172-175

基于河北区域数字地震台网资料,采用CAP波形反演方法计算2020-07-12唐山M_S5.1地震的震源机制解,同时采用sPL深度震相方法对震源深度进行精确测定。结果显示,唐山M_S5.1地震震源机制解节面Ⅰ走向143°、倾角83°、滑动角-14°,节面Ⅱ走向235°、倾角76°、滑动角-173°;sPL深度震相方法测定的主震震源深度为14 km,与CAP波形反演方法的计算结果一致。结合地震序列分布特征、等震线形态、区域地质构造及深地震反射剖面等资料分析认为,节面Ⅱ为发震断层面,并推测此次地震的发震断层为唐山-古冶断裂。  相似文献   

A Case Study of the Initiation of Parallel Convective Lines Back-Building from the South Side of a Mei-yu Front over Complex Terrain     

Qiwei WANG  Yi ZHANG  Kefeng ZHU  Zhemin TAN  Ming XUE 《大气科学进展》2021,38(5):717-736

Parallel back-building convective lines are often observed extending to the southwest of some mesoscale convective systems(MCSs)embedded in the mei-yu front in China.The convective lines with echo training behavior can quickly develop into a stronger convective group of echoes,resulting in locally heavy rainfall within the mei-yu front rainband.The initiation mechanism of the back-building convective lines is still unclear and is studied based on high-resolution numerical simulation of a case that occurred during 27?28 June 2013.In the present case,the new convection along the convective lines was found to be forced by nonuniform interaction between the cold outflow associated with the mei-yu front MCSs and the warm southerly airflow on the south side of the mei-yu front,which both are modified by local terrain.The mei-yu front MCSs evolved from the western to the eastern side of a basin surrounded by several mesoscale mountains and induced cold outflow centered over the eastern part of the basin.The strong southwest airflow ahead of the mei-yu front passed the Nanling Mountains and impacted the cold outflow within the basin.The nonuniform interaction led to the first stage of parallel convective line formation,in which the low mountains along the boundary of the two airflows enhanced the heterogeneity of their interaction.Subsequently,the convective group quickly developed from the first stage convective lines resulted in apparent precipitation cooling that enhanced the cold outflow and made the cold outflow a sharp southward windshift.The enhanced cold outflow pushed the warm southerly airflow southward and impacted the mountains on the southeast side of the basin,where the roughly parallel mountain valleys or gaps play a controlling role in a second stage formation of parallel convective lines.  相似文献   

The First Global Carbon Dioxide Flux Map Derived from TanSat Measurements     

Dongxu YANG  Yi LIU  Liang FENG  Jing WANG  Lu YAO  Zhaonan CAI  Sihong ZHU  Naimeng LU  Daren LYU 《大气科学进展》2021,38(9):1433-1443

Space-borne measurements of atmospheric greenhouse gas concentrations provide global observation constraints for top-down estimates of surface carbon flux.Here,the first estimates of the global distribution of carbon surface fluxes inferred from dry-air CO_2 column (XCO_2) measurements by the Chinese Global Carbon Dioxide Monitoring Scientific Experimental Satellite (Tan Sat) are presented.An ensemble transform Kalman filter (ETKF) data assimilation system coupled with the GEOS-Chem global chemistry transport model is used to optimally fit model simulations with the Tan Sat XCO_2 observations,which were retrieved using the Institute of Atmospheric Physics Carbon dioxide retrieval Algorithm for Satellite remote sensing (IAPCAS).High posterior error reduction (30%–50%) compared with a priori fluxes indicates that assimilating satellite XCO_2 measurements provides highly effective constraints on global carbon flux estimation.Their impacts are also highlighted by significant spatiotemporal shifts in flux patterns over regions critical to the global carbon budget,such as tropical South America and China.An integrated global land carbon net flux of 6.71±0.76 Gt C yr~(-1) over12 months (May 2017–April 2018) is estimated from the Tan Sat XCO_2 data,which is generally consistent with other inversions based on satellite data,such as the JAXA GOSAT and NASA OCO-2 XCO_2 retrievals.However,discrepancies were found in some regional flux estimates,particularly over the Southern Hemisphere,where there may still be uncorrected bias between satellite measurements due to the lack of independent reference observations.The results of this study provide the groundwork for further studies using current or future Tan Sat XCO_2 data together with other surfacebased and space-borne measurements to quantify biosphere–atmosphere carbon exchange.  相似文献