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221.
碎屑金红石:沉积物源的一种指针 总被引:3,自引:2,他引:1
近年来,碎屑金红石的研究已成为沉积物源区分析的一个新前沿。金红石的地球化学组成,尤其是Cr,Nb,Zr等微量元素的含量,对其母岩的形成条件和所经历的地质过程都具有重要的指示意义,同时,碎屑金红石在沉积、成岩过程中表现出极高的稳定性,因而是物源分析的理想指针矿物。首先介绍金红石的矿物学和地球化学基本性质,分析不同来源的金红石典型特征,重点阐述碎屑金红石在物源分析中运用的5个方面:①金红石重矿物比值;②金红石矿物化学成分Cr-Nb判别图解;③金红石Zr含量温度计;④金红石的U-Pb和(U-Th)/He定年;⑤金红石Lu-Hf同位素。综合上述5个方面的物源分析研究,可以获取金红石的母岩类型、形成温度及后期所经历的热演化史等信息。碎屑金红石的物源研究处于起步和探索阶段,仍存在一些亟需解决的问题。 相似文献
222.
Relationship Between the Western Pacific Subtropical High and the Subtropical East Asian Diabatic Heating During South China Heavy Rains in June 2005
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Based on the daily NCEP/NCAR reanalysis data, the position variation of the western Pacific subtropical high (WPSH) in June
2005 and its relation to the diabatic heating in the subtropical East Asia are analyzed using the complete vertical vorticity
equation. The results show that the position variation of the WPSH is indeed associated with the diabatic heating in the subtropical
East Asian areas. In comparison with June climatology, stronger heating on the north side of the WPSH and relatively weak
ITCZ (intertropical convergence zone) convection on the south side of the WPSH occurred in June 2005. Along with the northward
movement of the WPSH, the convective latent heating extended northward from the south side of the WPSH. The heating to the
west of the WPSH was generally greater than that inside the WPSH, and each significant enhancement of the heating field corresponded
to a subsequent westward extension of the WPSH. In the mid troposphere, the vertical variation of heating on the north of
the WPSH was greater than the climatology, which is unfavorable for the northward movement of the WPSH. On the other hand,
the vertical variation of heating south of the WPSH was largely smaller than the climatology, which is favorable for the anomalous
increase of anticyclonic vorticity, leading to the southward retreat of the WPSH. Before the westward extension of the WPSH
in late June 2005, the vertical variation of heating rates to (in) the west (east) of the WPSH was largely higher (lower)
than the climatology, which is in favor of the increase of anticyclonic (cyclonic) vorticity to (in) the west (east) of the
WPSH, inducing the subsequent westward extension of the WPSH. Similar features appeared in the lower troposphere. In a word,
the heating on the north-south, east-west of the WPSH worked together, resulting in the WPSH extending more southward and
westward in June 2005, which is favorable to the maintenance of the rainbelt in South China. 相似文献
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224.
地电阻率井下观测装置抗干扰能力实验研究 总被引:1,自引:1,他引:0
开展地电阻率深井观测系统对地面已知干扰源的抗干扰能力测试,对测试结果进行量化研究,分析地表电磁干扰对地电深井观测的影响程度,期望为将来地电深井方法的研究提供帮助. 相似文献
225.
深圳地区中生代火山地层分布区是我国东南沿海浙闽粤港火山活动带的一个重要组成部分,是我国沿海地区侏罗纪—白垩纪火山地层较有代表性地段,也是研究我国东南沿海侏罗纪—白垩纪火山活动的天然博物馆。近期通过野外观察,测制火山地层剖面,进行锆石同位素激光定年测试,对大鹏半岛国家地质公园中生代火山地层的时代提出新的认识,将原划分为上侏罗统高基坪群划分为早—中侏罗世塘厦组(181.8 Ma?)、中侏罗世吉岭湾组(165.8 Ma)、晚侏罗世梧桐山组(156.9~145.6 Ma)、晚侏罗世—早白垩世七娘山组(146.3~131.0 Ma)、早白垩世官草湖群等。 相似文献
226.
Late Jurassic-Early Cretaceous Northern Qaidam Basin, NW China: Implications for the earliest Cretaceous intracontinental tectonism 总被引:4,自引:0,他引:4
Lei Wu Ancheng Xiao Liqun WangZhongyan Shen Suping ZhouYuanzhong Chen Liang Wang Dong LiuJunya Guan 《Cretaceous Research》2011,32(4):552-564
Formation of Mesozoic western China, which was dominated by tectonic amalgamation along its southern margin and associated intracontinental tectonisms, holds a key for interpreting the succedent Cenozoic evolution. This paper presents new data including lithology, sedimentary facies, stratigraphic contact, seismic interpretation and paleo-structures within the Upper Jurassic-Lower Cretaceous strata in the northern Qaidam Basin, NW China. These data all account for a contractional tectonic deformation in the earliest Cretaceous. The South Qilian Shan, according to the sedimentary features and provenance analysis, reactivated and exhumated during the deformation, controlling the deposition of the Lower Cretaceous sequences. A simplified model for the Late Jurassic-Early Cretaceous paleogeography and tectonics of the northern Qaidam Basin is accordingly proposed. The results also support a ∼25° clockwise rotation of the Qaidam Basin since the Early Cretaceous and a more accurate Mesozoic evolution process for the basin. This earliest Cretaceous deformation, associated with the reactivation of the South Qilian Shan at the time, are part of the intracontinental tectonisms in central Asia during the Mesozoic, and probably driven by both the closure of the Mongol-Okhostk Ocean to the north and the collision of the Lhasa and the Qiangtang blocks to the south. 相似文献
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229.
Sediment transport in the Yellow Sea and East China Sea 总被引:2,自引:0,他引:2
Eight survey cruises in different seasons have been conducted in the Yellow Sea (YS) and East China Sea (ECS) during the period from 2000 to 2008. Suspended sediment concentration (SSC) and hydrological data were collected during each cruise. Data analysis showed that total suspended sediment mass was approximately 0.18 × 109 tons in the surveyed area during spring and autumn seasons. Highly turbid waters were found in the shallow waters between the Subei coast, the Changjiang estuary and the Zhejiang coast with seasonal variations. 相似文献
230.
设计基于DTU的强振记录终端,采用SOC系列C8051F015型单片机对MEMS加速度计的输出信号进行A/D转换,监测待测体所经受的强振加速度值,并通过DTU内嵌的GPRS无线网络通讯方式将数据发送到远程数据中心.该系统具有体积小,安装与操作方便,免维护等特性. 相似文献