【摘 要】
：
Reworked detrital sediments were discovered in the syn-rift to post-rift Cretaceous to Quaternary (Pleis-tocene) detrital deposits of the Douala coastal sub-basin in the eastern margin of the South Atlantic Ocean at West Cameroon.This contribution present
【机 构】
：
Department of Earth Sciences,University of Dschang,P.O.Box 67,Dschang,Cameroon;Higher Institute of C
论文部分内容阅读
Reworked detrital sediments were discovered in the syn-rift to post-rift Cretaceous to Quaternary (Pleis-tocene) detrital deposits of the Douala coastal sub-basin in the eastern margin of the South Atlantic Ocean at West Cameroon.This contribution presents the geochemical,mineralogical,and sedimentological data to constrain the origin of these reworked sediments.The investigated samples are characterized by the high values of Plagioclase Index of Alteration (PIA,97.83-99.90),Chemical Index of Alteration (CIA,71.9-99.08),and Chemical Index of Weathering (CIW,98.67-99.90).Data gleaned from these indices suggest that the reworked sediments and their potential source rocks experienced severe weathering.The A-CN-K plot along with the mineralogical indicates a probably post-depositional K-enrichment.The high light rare earth elements (LREE)/heavy rare earth elements(HREE) ratios (15.82-79.13) suggest that the reworked were mainly derived from felsic igneous rocks.This interpretation is further confirmed by the Zr versus TiO2,TiO2/Al2O3,Th/Co versus La/Sc,and La/Th versus Th/Yb plots,which indicate felsic igneous and silicic source rocks.Meanwhile,the high variability of LREE/HREE ratios (15.82-79.13) and the positive Eu anomalies(1.10-1.32) of studied samples could indicate a little con-tribution of mafic source rocks.Analysis of the distribution of the heavy minerals (e.g.tourmaline,aluminum silicate,and rutile) revealed that these felsic and silicic source rocks are mainly granite and gneiss,probably belonging to the Nyong Group and the Western part of the Neoproterozoic Yaounde Group.The morphoscopic analyses of the host rocks (very angular to angular shapes) have revealed that the reworked sediments have proximal to subproximal onshore origins,probably from former sedimentary deposits,as is indicated by variation of their color.The tectonic discriminant diagram indicates the Oceanic Island Arc and Active Continental Margin which are inconsistent with the geological history of the Douala coastal sub-basin and could be explained by the recycling effect experienced by studied sediments which have been deposited in the coastal plain to the fluvial environment in the Low System Track context.
其他文献
研发并筛选具有新的作用机制的高效低毒HIV抑制剂,仍是目前抗艾滋病药物研发的前沿科研领域.中医药防治艾滋病,成为治疗艾滋病重要手段.从丰富的中药资源宝库中筛选出更常见的中药或者草药成分的抗艾滋病药物具有重要的临床应用和推广意义.
Despite progress over the past few years in developing efficient low-cost catalysts,precious metals are still the best catalysts for hydrogen evolution reaction (HER),oxygen evolution reaction (OER),and oxygen reduction reaction (ORR).However,the natural
针对传统施工力学模拟方法的局限性,首先提出了分步建模施工模拟理论,基于施工步之间力学非线性平衡方程,通过二次开发,采用基于ANSYS的分步建模施工仿真分析技术,揭示了不同施工步之间力学响应变化规律,完善了大跨度钢结构精细化施工理论.其次提出了考虑钢结构施工焊接残余应力的简化模拟技术、基于遗传算法的施工过程优化通用算法和高效的风振响应计算理论,通过沈阳华晨宝马、天津于家堡站房大型钢结构等项目应用,实现了大跨度钢结构施工的精细化.最后提出了考虑节点半刚性特性和构件初始缺陷的钢结构计算理论与数值算法,完善了临时
为贯彻落实国家关于“建立健全国土空间规划动态监测评估预警和实施监管机制”的要求,根据国家有关部门关于国土空间规划全过程管理、全程留痕的具体要求,按照广东“数字政府”改革和“一网统管”工作部署,高质量完成国家赋予广东试点省的建设任务,项目采用“全省统筹、分类实施、云端部署”模式,建设了省市县三级联动、上下贯通、横向连通的空间规划实施监督信息系统,为广东建设覆盖全省、动态更新、权威统一的国土空间规划“一张图”和全过程监管提供强有力信息化支撑(图1).
随着政府和公众对天气预报多样化需求的迅速增长,目前天气预报业务中以点代面的传统站点预报已越来越难以满足社会服务的需求,尤其是对于海南这样一个气象灾害种类复杂多样(台风、持续性暴雨、强对流、大雾、高温等),农业、旅游服务业、渔业所占国民经济比重较大的海洋大省,基于更为先进的预报预测技术,涵盖全海域的定点、定时、定量精细化网格天气预报服务需求显得更为急迫.项目联合国家气象中心天气预报技术研发室和海南晓晨科技公司,针对风向风速、降水、温度、相对湿度、云量、能见度等预报产品及雷暴大风、暴雨、高温等灾害性天气预警的
陆军医大学第二附属医院黄岚教授领衔的“高原心血管响应机制与急性高原病防治系列研究与应用”项目在全国244项医学项目中脱颖而出,获2020年度中华医学科技奖一等奖.项目在国家公益性行业(卫生)科研专项等20余项课题资助下,历时15年,团队克服高原环境恶劣、科技水平落后、科研组织困难等诸多不利因素,组织多单位、多学科协作攻关,建立了超过10万人次国际最大规模的高原现场研究队列,系统阐述了高原心血管响应的特征、机制、临床意义,揭示其在急性高原病发生中的主导地位.项目全面评价了急进高原人群心血管主要生理参数、心电
研究了不同肥料运筹对常农粳12号产量及产量构成因子的影响,结果表明:以18,kg每667,m2的氮肥用量,在倒4叶露出时施用适量穗肥(不施保花肥)产量最高,综合经济效益最高.
“新型移动式有机废弃物资源化装备及其技术模式研究”是国家重点研发计划项目,由中国科学院城市环境研究所、中国科学院水利部成都山地灾害与环境研究所、集美大学、厦门中科城环新能源有限公司、厦门市环境卫生中心和希腊海勒斯研究与技术中心化学工艺与能源研究所共同完成.课题针对目前食品、农业和生物技术领域全球关注的热点问题——有机废弃物的资源化利用问题,中欧合作双方通过有机废弃物养分回收与污染物去除、能源回收、技术模式与产业化推广等方面的优势互补,研发移动式有机废弃物资源化准备与技术模式.通过国际合作,以实现可复制、能
Poverty eradication is a realistic requirement for the addressing of the urban-rural development imbalance. It consolidates the achievements of the poverty alleviation, and accelerates the realization of the United Nations Sustainable Development Goals. I
传感器校正产品质量的稳定性和精细化处理能力是制约遥感卫星数据高水平应用的瓶颈.项目以提高遥感卫星应用效能为目标,突破了立体影像间及全色、多光谱影像间局部系统误差校正、多源测绘立体影像融合提取DSM、SAR影像无底图自动纠正、高光谱影像条带噪声去除等关键技术,制定了DOM数据生产、DSM数据生产、SAR影像DOM数据生产、高光谱影像反射率DOM生产的业务化生产流程,构建了多源卫星遥感影像全自动精化处理系统,实现了包括十几类国产遥感卫星在内的国内外主流遥感卫星数据的业务化生产,促进了卫星遥感应用的高质量发展.