检索结果-南通市图书馆

Reform of Carbonate Rock Subsurface by Crustose Lichens and Its Environmental Significance

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 1998年第1期72卷 94-99页

作者： CAO Jianhua and WANG Fuxinginstitute of Karst Geology, chinese academy of geological sciences, Guilin, Guanxi 541004 Xiao Pinfang liu {3. institute of Karst Geology Chinese Academy of Geological Sciences Guilin Guanxi 541004

Crustose lichens are distributed extensively in karst areas in Southern China. They can be found on the surface of carbonate rocks. Through biophysical and biochemical processes, crustose lichens reform the subsurface of carbonate rocks and in the meanwhile change their physical and chemical properties: (1) the mechanical strength decreases by 17.04° on average (up to 3..2°); (2) the chemical solution surface area increases from 28.26% to 75.3.% (lichen microholes considered only); and (3. the water-holding capacity is greatly improved. Comparative field experiments between biokarst samples underneath crustose lichens and fresh rock samples with the same composition and texture show that the corrosional rate of carbonate rocks of the former is 1.264–1.643.times higher than that of the latter. Crustose lichens are considered as an activator of the surface corrosion of carbonate rocks.

关键词： crustose lichen carbonate rock biokarst corrosion environmental significance

geological Characteristics and Manifestations of geological Processes of Sequence Boundaries and Their Vicinities

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 1997年第4期71卷 386-394页

作者： Xiao Linping Testing Centre of Geotechnical Engineering, Southwest Jiaotong Universityand Zhao YuguangChengdu institute of mineral Resources, chinese academy of geological sciences, Chengdu, Sichuan, 610082 {3. xinzhu Testing Centre of Geotechnical Engineering Southwest Jiaotong University Chengdu institute of mineral Resources Chinese Academy of Geological Sciences Chengdu Sichuan 610082

This paper discusses the geological characteristics and architectures of sequence boundaries and their vicinities and has proposed a classification scheme for the sequence boundaries, which can thus be grouped into three types and eight categories: type I includes exposed truncated surface, palaeosol surface, palaeokarst surface and exposed surface; type Ⅱ boundaries include structural transitional surface during sea-level fall and transgressive onlap surface; and type Ⅲ includes submarine erosional diagenetic diastem and event surface. A study has been made for the three major boundaries lying between the Permian and pre-Permian, the Permian and Triassic, and the Middle and Lower Triassic respectively in terms of multiple disciplines such as lithostratigraphy, biostratigraphy, magnetostratigraphy and carbon and oxygen isotopic geology. These three boundaries are ascribed to type I , typeⅡ and typeⅢ, respectively.

关键词： sequence boundaries architectural analysis biotic succession magnetopolarity superperiod carbon and oxygen isotopes

Carboniferous Post-collisional Rift Volcanism of the Tianshan Mountains, Northwestern China

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2003年第3期77卷 338-360页

作者： XIA Linqi, XU Xueyi, XIA Zuchun, LI Xiangmin, MA Zhongping and WANG Lishe Xi’an institute of Geology and mineral Resources, China geological Survey, Xi’an, Shaanxi 710054 E-mail: geologyx@***. {3. Shuchun and {3. xinzhu Xian Inst Geol & mineral Resources China Geol Surv Xian 710054 Shaanxi Peoples R China

The Tianshan Carboniferous post-collisional rift volcanic rocks occur in northwestern China as a large igneous province. Based on petrogeochemical data, the Tianshan Carboniferous post-collisional rift basic lavas can be classified into two major magma types: (1) the low-Ti/Y type situated in the eastern-central Tianshan area, which exhibits low Ti/Y (3.55%), and relatively high Fe2O3. (6.4-11.5%); (2) the high-Ti/Y type situated in the western Tianshan area, which has high Ti/Y (>500), Ce/Yb (>11) and SiO2 (49-55%), and relatively low Fe2O3. (5.8-7.8%). Elemental data suggest that chemical variations of the low-Ti/Y and high-Ti/Y lavas cannot be explained by fractional crystallization from a common parental magma. The Tianshan Carboniferous basic lavas originated most likely from an OIB-like asthenospheric mantle source (87Sr/86Sr(t) ≈ 0.703.0.705, eNd(0 = +4 to +7). The crustal contamination and continental lithospheric mantle have also contributed significantly to the formation of the basic lavas of the Tianshan Carboniferous post-collisional rift. The silicic lavas were probably generated by partial melting of the crust. The data of this study show that spatial petrogeochemical variations exist in the Carboniferous post-collisional rift volcanics province in the Tianshan region. Occurrence of the thickest volcanics dominated by tholeiitic lavas may imply that the center of the mantle-melting anomaly (mantle plume) was in the eastern Tianshan area at that time. The basic volcanic magmas in the eastern Tianshan area were generated by a relatively high degree of partial melting of the mantle source around the spinel-garnet transition zone, whereas the alkaline basaltic lavas are of the dominant magma type in the western Tianshan area, which were generated by a low degree of partial melting of the mantle source within the stable garnet region, thus the basic lavas of the western Tianshan area might have resulted from relatively thick li

关键词： Carboniferous post-collisional rift volcanics geochemistry petrogenesis asthenosphere lithosphere Tianshan Mountains NW China

Isotope Tracing and Prospecting Assessment of Gold-Silver deposits in Zhejiang Province

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 1997年第3期71卷 293-304页

作者： Chen Haoshou and Xu Butai Department of Earth sciences, Zhejiang University, Hangzhou, Zhejiang Zhejiang institute of Geology and {3. Resources, Hangzhou, Zhejiang liu xinzhu Department of Earth sciences Zhejiang University Hangzhou Zhejiang Zhejiang institute of Geology and mineral Resources Hangzhou Zhejiang [?]Chen Haoshou Born in 193. graduated from the Geochemistry Specialty of the Department of Geology Peking University in 1964. He has long been engaged in researches on isotopic geochemistry and worked successively in Tianjin Institute of Geology and Mineral Resources Xi' an Institute of Geology and Mineral Resources and Yichang Institute of Geology and Mineral Resource under the Chinese Academy of Geological Sciences. He is now professor of Zhejiang 1Jniversity.

Three different types of gold and silver deposits in Zhejiang Province(Huangshan gold deposit, Zhilingtou gold-silver deposit and Haoshi silver deposit) showmarked differences in lead and strontium isotopic composition, suggesting three differentsources and geneses of these deposits. The Huangshan gold deposit features low initial Srisotope ratios and low μ values or low content of radiogenic Pb and its ore-forming materialscame primarily from the upper mantle; the Zhilingtou gold-silver deposit shows high initial Srisotope ratios and high μ values or high content of radiogenic Pb and the ore-forming materialswere derived mainly from the upper crust; and the Haoshi silver deposit has its Pb and Srisotope ratios between the above two cases with the ore-forming materials stemming from boththe mantle and the crust. The characteristic Pb isotopic composition may serve as an indicatorfor prospecting for different types of ore deposits.

关键词： isotope tracing gold deposit silver deposit Zhejiang Province

Geochronology and mineralogy of the Weishan carbonatite in Shandong province, eastern China

在线全文

学校读者我要写书评

暂无评论

Geoscience Frontiers 2019年第2期10卷 769-785页

作者： Chen Wang Jianchao liu Haidong Zhang xinzhu Zhang Deming Zhang Zhixuan Xi Zijie Wang School of Earth Science and Resources Chang'an University Department of Geology Northwest University Weishan mining (Group) Co.Ltd. Shandong Provincial 4th Exploration institute of Geology and mineral Resources

The Weishan REE deposit is located at the eastern part of North China Craton(NCC), western Shandong Province. The REE-bearing carbonatite occur as veins associated with aegirine syenite. LA-ICP-MS bastnaesite Th-Pb ages(129 Ma) of the Weishan carbonatite show that the carbonatite formed contemporary with the aegirine syenite. Based on the petrographic and geochemical characteristics of calcite, the REEbearing carbonatite mainly consists of Generation-1 igneous calcite(G-1 calcite) with a small amount of Generation-2 hydrothermal calcite(G-2 calcite). Furthermore, the Weishan apatite is characterized by high Sr, LREE and low Y contents, and the carbonatite is rich in Sr, Ba and LREE contents. The δ^(13.Cv-PDB(-6.5‰ to -7.9‰) and δ^(13.OV-SMOW(8.48‰-9.67‰) values are similar to those of primary, mantlederived carbonatites. The above research supports that the carbonatite of the Weishan REE deposit is igneous carbonatite. Besides, the high Sr/Y, Th/U, Sr and Ba of the apatite indicate that the magma source of the Weishan REE deposit was enriched lithospheric mantle, which have suffered the fluid metasomatism. Taken together with the Mesozoic tectono-magmatic activities, the NW and NWW subduction of Izanagi plate along with lithosphere delamination and thinning of the North China plate support the formation of the Weishan REE deposit. Accordingly, the mineralization model of the Weishan REE deposit was concluded: The spatial-temporal relationships coupled with rare and trace element characteristics for both carbonatite and syenite suggest that the carbonatite melt was separated from the CO_2-rich silicate melt by liquid immiscibility. The G-1 calcites were crystallized from the carbonatite melt, which made the residual melt rich in rare earth elements. Due to the common origin of G-1 and G-2 calcites, the REE-rich magmatic hydrothermal was subsequently separated from the melt. After that, large numbers of rare earth minerals were produced from the magmatic hydrothermal

关键词： Weishan REE deposit Carbonatite Calcite Apatite Deposit model

Separate Analysis of Remote Sensing Information of Structures of Different geological Periods and Quantitative Study of Corresponding Tectonic Stress Fields

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 1997年第3期71卷 344-354页

作者： Yang Wunian and Zhu Zhangsen institute of Remote Sensing and GIS, Chengdu University of Technology,Chengdu, Sichuan liu xinzhu Yang Wencai institute of Remote Sensing and GIS Chengdu University of Technology Chengdu Sichuan [?]Yang Wunian Born in Zhongwei Ningxia province in 1954. He works as Director of the Institute of Remote Sensing & GIS of Chengdu University of Technology and a member of the Committee on Remote Sensing for Geology of the Geological Society of China. He is particularly interested in remote sensing geology and mathematic geology. His current major studies include applications of remote sensing techniques in exploration of land & resources.

The structural feature shown on a remote sensing image is a synthetic result ofcombination of the deformations produced during the entire geological history of an ***, the respective tectonic stress field of each of the different stages in the complexdeformation of an area can be reconstructed in three steps: (1) geological structures formed atdifferent times are distinguished in remote sensing image interpretation; (2) structuraldeformation fields at different stages are determined by analyzing relationships betweenmicrostructures (joints and fractures) and the related structures (folds and faults); and (3.tectonic stress fields at different stages are respectively recovered through a study of the featuresof structural deformation fields in different periods. Circular structures and related circlular and radial joints are correlated in space to con-cealed structural rises. The authors propose a new method for establishing a natural model ofthe concealed structural rises and calculating the tectonic stress field by using quantitative dataof the remote sensing information of circular structures and related linear structures.

关键词： separate analysis of the remote sensing information field circular structure linear structure stress field quantitative analysis 3.dimensional colour structural block diagram

应力波作用下含大型结构面岩体垮塌动力失稳机制

在线全文

学校读者我要写书评

暂无评论

岩石力学与工程学报 2021年第10期40卷 2003-2014页

作者：刘啸华心祝黄志国杨朋杨森常贯峰安徽理工大学深部煤矿采动响应与灾害防控国家重点实验室安徽淮南232001 安徽理工大学矿业工程学院安徽淮南232001 中煤科工集团沈阳研究院有限公司煤矿安全技术国家重点实验室辽宁抚顺113000 东华理工大学地球科学学院江西南昌330013

不连续结构面对爆炸应力波在岩体中的传播有很大影响,研究应力波作用下含大型结构面岩体动力垮塌失稳机制,为含结构面等地质构造条件下岩体开采及稳定性控制提供理论依据。以冬瓜山铜矿56–8#矿房采场回采诱发相邻56–7#矿柱采场垮塌为... 详细信息

不连续结构面对爆炸应力波在岩体中的传播有很大影响,研究应力波作用下含大型结构面岩体动力垮塌失稳机制,为含结构面等地质构造条件下岩体开采及稳定性控制提供理论依据。以冬瓜山铜矿56–8#矿房采场回采诱发相邻56–7#矿柱采场垮塌为工程背景,建立结构面剪切滑移失稳力学模型,基于莫尔–库仑强度准则,采用理论分析方法计算了爆炸应力波通过结构面的透、反射系数,分析应力波通过结构面的应力响应特征;推导结构面发生剪切滑移的能量判据及应力判据,获得结构面的发生剪切失稳的条件。通过对结构面抗剪强度参数进行不断弱化,研究了微差爆破对结构面的破坏规律。研究表明:(1)入射角在一定范围内,反射波不发生相位延迟现象,并且在此入射角范围内,能量耗散系数大于0,结构面发生剪切滑移;(2)结构面是否发生剪切滑移失稳与结构面抗剪强度参数(内摩擦角、黏聚力)及应力波入射角、爆源距结构面距离有关;爆源距结构面的距离越远,结构面的抗剪强度参数越大,越不容易发生剪切滑移失稳。(3.微差爆破造成结构面强度参数不断弱化,使其发生剪切破坏变得容易,当结构面参数达到了发生剪切滑移的临界条件时,则56–7#矿柱采场发生垮塌。

关键词：采矿工程动力失稳爆炸应力波透反射系数能量判据应力判据

在线全文

学校读者我要写书评

暂无评论

锚注支护在桃园北四采区7244机巷的应用

华北科技学院学报 2009年第1期6卷 9-12页

作者：刘淑华心祝周华龙毕善昌安徽理工大学能源与安全学院安徽淮南市232001 重庆工程职业技术学院重庆400037

在对桃园矿北四采区7244机巷工程支护分析的基础上,针对其特殊地质情况,设计合理的支护断面,确定合理支护参数的锚注支护方案。方案实施后在支护现场设立两个测站对锚杆的载荷、多点位移计的位移以及围岩收敛值进行测定,并绘出其随时间... 详细信息

在对桃园矿北四采区7244机巷工程支护分析的基础上,针对其特殊地质情况,设计合理的支护断面,确定合理支护参数的锚注支护方案。方案实施后在支护现场设立两个测站对锚杆的载荷、多点位移计的位移以及围岩收敛值进行测定,并绘出其随时间的变化曲线。锚注支护确保了桃园矿井的安全生产,为我国煤矿井下软岩巷道治理提供了一条行之有效技术途径。

关键词：锚注水泥浆浆液巷道布置巷道监测

南海中沙群岛海域温盐结构时空变化特征及其控制因素

在线全文

学校读者我要写书评

暂无评论

海洋地质与第四纪地质 2022年第2期42卷 1-14页

作者：黄诚吴能友吴晓刘时桥张经纬许丞刘亮董新柱陈靓中国海洋大学青岛266100 中国地质调查局海口海洋地质调查中心海口570100 中国地质调查局青岛海洋地质研究所青岛266237

南海中沙群岛海域夏秋季水团实测温盐深数据统计分析结果表明,研究区海水表层温度为3..0~3..2℃,最高温度位于中沙海台区域;表层盐度为3..6~3..1 PSU,最高盐度分布在西北部东岛海域附近;底层温度1~25℃,盐度3..1~3..2 PSU,最高盐度分布... 详细信息

南海中沙群岛海域夏秋季水团实测温盐深数据统计分析结果表明,研究区海水表层温度为3..0~3..2℃,最高温度位于中沙海台区域;表层盐度为3..6~3..1 PSU,最高盐度分布在西北部东岛海域附近;底层温度1~25℃,盐度3..1~3..2 PSU,最高盐度分布在工区东南角。总体上,研究区水团温盐结构表现为表层高温低盐、底层低温高盐的特征,混合层深度为20~90 m。研究区表、中、底层水体垂向流速各不相同,流速为0.01~0.22 m/s。根据FVCOM模型分析了调查区温度、盐度季节性变化特征,冬季,研究区南侧的海域海表温度明显高于北侧,南北温差显著;夏季,海表温盐分布受到台风作用较为明显,海表温度的空间分布趋于均一。数值模拟表明,研究区流场整体表现为冬夏季强、春秋季较弱的季节性变化特征。模拟结果显示,极端天气在短期内对研究区温盐结构产生显著影响,表现为海表温度降低、混合层深度增加,水体垂向混合作用增强。

关键词：温盐结构 FVCOM数值模型混合层极端气候中沙群岛海域