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The vast expanse of Mesozoic igneous rocks in Hong Kong contain important geological records of late Mesozoic magmatic events and tectonic processes from the coastal region of Southeast China. Of these,the Ping Chau Formation in the northwestern New Territories is the youngest known stratum. We perform a detailed study of the volcanic rocks of the Ping Chau Formation utilizing zircon U-Pb dating,with major and trace elements geochemistry. LA-ICP-MS zircon U-Pb data reveal Early Cretaceous age from two volcanic rock samples, with zircon crystallization from magmas at 140.3 ± 0.8 Ma and 139.3 ± 0.9 Ma,respectively. These rocks have high contents of total alkalis(Na_2O + K_2O = 5.58-9.45 wt.%), high-field-strength elements and light rare earth elements, conspicuous negative Eu anomalies, and depletions in Nb, Ta, Ti, Sr, Ba and P. Using this data, in combination with previous studies on the late Mesozoic volcanic belt in Southeast China, we propose that the volcanic rocks of the Ping Chau Formation probably originated from deep melting of the crust in a back-arc extensional setting induced by the subduction of the paleo-Pacific Plate. This formation represents the final stages of Early Cretaceous volcanic activity in Hong Kong, as associated with large-scale lithospheric extension, thinning and magmatism. Our results provide new information that can be used in evaluating the significance of Early Cretaceous volcanism and tectonics in Southeast China. 相似文献
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长--平陆相红色盆地北东段量化沉积学特征及其演化 总被引：1，自引：0，他引：1
长－平陆相红色盆地北东段（系指赣西北红层分布区）由三期5个冲积扇体组成。非同期扇体分别由特定界面所分隔。山口位于盆地北侧,古流向由北向南、南东或南西呈扇形撒开;最大砾石平均体积及混杂系数在扇根处为最大值,向扇中、扇缘呈非线性递减;砾石成分严格受物源区的制约。根据量化沉积学特征及成生背景分析,该区大致经历了初始孕育期、分段剥蚀充填期及后期构造改造三大演化阶段。洪积事件始于晚白垩世、止于早第三纪始新世-渐新世。 相似文献
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永平铜矿石微生物槽浸初步实验研究 总被引：1，自引：0，他引：1
以永平铜矿石为研究对象，通过有菌与无菌对比实验，研究了微生物槽浸铜过程中主要技术参数(Fe^3 ，Fe^2 ,pH，Eh，Cu)的变化规律。在此基础上，评价了永平铜矿微生物槽浸铜的可行性。 相似文献
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现代性、全球化和城市化催生了当代的怀旧现象并使其成为国内外学界关注的重要话题。涵盖人们衣食住行和精神文化消费领域的怀旧消费风靡全球,以城市怀旧为主题的特殊消费空间和文化空间作为怀旧消费实践过程中的时空综合体,其地方建构的过程及社会文化意义值得文化地理学者进行探讨。文章以广州百年老字号西餐厅太平馆为案例,通过参与式观察和半结构式访谈等质性研究方法,并收集相关媒体报道作为资料来源。从怀旧餐厅的物质空间建构和情感空间建构2个维度对其地方建构的过程,以及此空间与消费者之间的互动关系进行探究。研究表明,太平馆作为怀旧消费空间,经营者通过对物质空间的主体性建构再现地方记忆,使得地方感得以再生产;而与此同时消费者则通过在怀旧空间中的消费实践获得归属和认同等情感体验,并成为了情感空间建构的积极主体,通过对太平馆的地方依恋与地方认同积极推动怀旧地方的持续建构。 相似文献
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Michael F. Ridd Christopher K. Morley 《Proceedings of the Geologists' Association. Geologists' Association》2011,122(1):143-156
A study of Google Earth images has revealed a hitherto-unrecorded gently curved lineament within the southern marginal zone of the Khorat Plateau in eastern Thailand. The lineament, confirmed by digital elevation model (DEM) images, is at least 130 km long and coincides with a dip reversal of the Mesozoic Khorat Group. It is interpreted here as a fault, named the Khao Yai Fault, and it has characteristics which make it unusual within the Khorat Plateau. The fault forms the northern boundary of a belt of several ENE-WSW trending fault splays which are thought to link with the Mae Ping Fault further south; this is interpreted as a left-stepping, sinistral strike-slip duplex about 50 km wide and 150 km long. Apatite fission track data indicate that exhumation began during the earliest Palaeogene.The Khao Yai Fault is considered in its regional context which includes the Cardamomes Mountains of Cambodia, the offshore Phuquoc-Kampot Basin, and the Khao Thalai Red-beds outlier of the Khorat Group in Southeast Thailand. The latter is interpreted as a down-faulted sliver of the Khorat Group in the Tha Mai Fault belt which is thought, in turn, to be a splay of Thailand's other major regional fault, the Three Pagodas Fault. Carboniferous, Permian and Triassic shallow-marine rocks with unusual faunas occur in a limited NNW-SSE trending zone to the west and NNW of the Tha Mai Fault and it is suggested that wrench movement on the fault played a part in the emplacement of these rocks. 相似文献
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ABSTRACTEstimating river flows at ungauged sites is generally recognised as an important area of research. In countries or regions with rapid land development and sparse hydrological gauging networks, three particular challenges may arise—data scarcity, data quality, and hydrological non-stationarity. Using data from 44 gauged sub-catchments of the upper Ping catchment in northern Thailand from the period 1995–2006, three relevant flow response indices (runoff coefficient, base flow index and seasonal elasticity of flow) were regionalised by regression against available catchment properties. The runoff coefficient was the most successfully regionalised, followed by base flow index and lastly the seasonal elasticity. The non-stationarity (represented by the differences between two 6-year sub-periods) was significant both in the flow response indices and in land use indices; however relationships between the two sets of indices were weak. The regression equations derived from regionalisation were not helpful in predicting the non-stationarity in the flow indices except somewhat for the runoff coefficient. A partly subjective data quality scoring system was devised, and showed the clear influence of rainfall and flow data quality on regionalisation uncertainty. Recommendations towards improving data support for hydrological regionalisation in Thailand include more relevant soils databases, improved records of abstractions and investment in the gauge network. Widening of the regionalisation beyond the upper Ping and renewed efforts at using remotely sensed rainfall data are other possible ways forward.
EDITOR Z.W. Kundzewicz ASSOCIATE EDITOR T. Wagener 相似文献
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李东海 《水文地质工程地质》1993,20(5):53-54
通过对平顶山矿区大气降水、地表水和地下水的氢、氧环境同位素的分析研究,利用稳定同位素氘和氧-18的关系,分析确定岩溶地下水的起源和形成,根据放射性同位素浓度的变化规律,推算在现有开采深度内各地岩溶地下水的年龄。 相似文献