【摘 要】
：
The Cuddalore Formation of the Cauvery Basin received siliciclastic detritus from inland areas of the Southern Granulite Terrain (SGT).It represented continental-fluvial sedimentation in the eastern conti-nental margin of South India during the Miocene.In
【机 构】
：
Department of Earth Sciences,Pondicherry University,Pondicherry 605014,India
论文部分内容阅读
The Cuddalore Formation of the Cauvery Basin received siliciclastic detritus from inland areas of the Southern Granulite Terrain (SGT).It represented continental-fluvial sedimentation in the eastern conti-nental margin of South India during the Miocene.Indian Summer Monsoon was thought to be initiated in the early Miocene and intensified during the middle Miocene causing major climatic shifts in the Indian subcon-tinent.In the present work,detailed mineralogical and geochemical studies on the siliciclastic Cuddalore Formation have been carried out to understand the provenance and paleoclimatic conditions during the Miocene.The paleocurrent direction,textural immaturity and framework detrital modes of sandstones suggest rapid uplift of basement and sediment source from nearby Madras Block of SGT.Various diagnostic immobile trace element ratios such as Th/Sc,Co/Th,La/Sc,La/Co suggest a tonalite-trondhjemite-granodior-ite-charnockite provenance,and somewhat more felsic composition of source area compared to the present upper continental crust (UCC).Rare earth element mixed model suggests that sediments were dominantly(80％) sourced from felsic charnockite,with a minor contribution (20％) from mafic granulites.Higher abun-dance of advanced-weathering products like kaolinite,very high (＞98) chemical index of alteration (ClA)values,severe depletion of mobile elements (Ca,Na,K,Mg,Ba,Rb) in comparison to UCC,significantly higher αMg,αCa,αNa,αK,αSr and αBa values (higher than the unity),all suggest the extreme chemical weathering in source terrain and/or in the sedimentary basin.Calculations based on CIA show high average surface tem-perature between 29.3 ℃ and 29.5 ℃ and high mean annual precipitation ranging from 2339 mm/yr to 2467 mm/yr.The geochemical data are consistent with the paleogeographic position of the depositional basin(Cauvery Basin) and suggest the deposition of Cuddalore sediments (the Cuddalore Formation) in a near-equatorial location under a warm climate condition with abundant monsoonal precipitation.
其他文献
以福州地区为研究区,采用新提出的城市热异常越级融合提取算法(UTALFE)消除城市热岛获得地表温度、区分早期与晚期燕山期侵入岩作为改进,融合地质背景、地理背景、地球物理3类数据共7个因子进行建模,并结合地热温标对圈定的地热潜力区进行验证.模型评价结果表明,加权信息量模型预测能力优于信息量模型.福州地区高地热潜力地区的分布与主要水系的分布存在明显空间相关性,市区、县区附近区域的地热潜力均较高,未来可以考虑在闽侯光明、闽清汤兜两处开展干热岩远景勘探与研究.
The Spiti Shale Formation is a widely distributed stratigraphic unit of the passive northern margin of the Indian craton,deposited between the Callovian and earliest Cretaceous.The siliciclastic strata are dominated by dark-grey to black argillaceous silt
以福建省为例,运用动态耦合最优化模型,模拟出在水资源总量、用水效率和纳污限制多目标控制下,2012—2025年福建省污水处理技术选择和设施建设方案、产业结构优化方案的最优解集.模拟结果显示:1)膜生物处理技术MBR可被大量用于改善福建省污水治理水平.2)2012—2025年,福建省通过新增污水处理设施24处,使污水处理能力由11.5亿m3增加到15.3亿m3,再生水回用率由5.3％上升到23.2％.3)在水资源总量和污染物质减排多目标约束下,主导产业因高耗水、高排污受限,使GRP年均增速低于发展规划目标.
Encrusting foraminifers locally can play an essential reef-forming role such as in the Carnian fossiliferous Hallstatt Limestones of Austria where a dense succession of hardgrounds occurs with numerous small buildups (up to 2 cm high) composed of sessile
The Late Cambrian (Furongian) Chaomidian Formation accumulated in an epeiric sea that covered a large part of the North China Plate and extended from China to Korea.The depositional environment of the formation is commonly considered to have been affected
Mummified fossil woods of Liquidombar from the Miocene of the Guiping Basin of Guangxi and the upper Pleistocene sediments of the Maoming Basin of Guangdong,South China are recognized as the new species Liquidambar guipingensis sp.nov.and the extant speci
To determine the characteristics and potential indicators of modern typhoon deposition in a sandy lagoon off the coast of Guangdong Province (southern China),we analysed the 210Pb,sedimentology,and microfossils of samples from ten cores obtained before an
In the Bay of Bengal,the Andaman and Nicobar Islands represent part of the Burma-Sunda-Java subduction complex.The Islands are composed of sediments ranging in age from Jurassic to Recent,repre-sented by ophiolites,flysch sediments,along with deep marine
This study focuses on the close association between Devonian reefs and the strata-bound ore deposits in South China.For the first time,the development of Devonian reefs was subdivided into three stages,respectively as the initial,succeeding and peak stage
Recent advances in the understanding of deltaic deposits provide new tools for the study and analysis of deltaic deposits in shallow epicontinental seas.After the introduction of sequence stratigraphic concepts,meter-scale coarsening and thickening upward