The formation of authigenic deposits during Paleogene warm climatic intervals: a review

来源 :古地理学报(英文版) | 被引量 : 0次 | 上传用户:a421455206a
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
Although Paleogene warm climatic intervals have received considerable attention for atmospheric and oceanographic changes,the authigenic mineralization associated with these time spans remains overlooked.An extensive review of the literature reveals a close correspondence between the high abundance of glauconite and warm climatic intervals during the Paleogene period.The abundance of phosphorite,ironstone,lignite and black shale deposits reveals similar trends.Although investigated thoroughly,the origin of these authigenic deposits is never understood in the background of Paleogene warming climatic intervals.A combination of factors like warm seawater,hypoxic shelf,low rate of sedimentation,and enhanced rate of continental weathering facilitated the glauconitization.The last factor caused the excess supply of nutrients,including Fe,Si,K,Mg and Al through the rivers,the cations needed for the formation of glauconite.The excessive inflow of nutrient-rich freshwater into the shallow seas further ensured high organic productivity and stratification in shallow shelves,causing hypoxia.The consequent rapid rise in sea-level during the warm periods created extensive low-relief shallow marine shelves starved in sediments.Oxygen-deficiency in the shallow marine environment facilitated the fixation of Fe into the glauconite structure.The inflow of nutrient-rich water during the warm climatic intervals facilitated the formation of phosphorite,ironstone,and organic-matter-rich sedimentary deposits as well.Although global factors primarily controlled the formation of these authigenic deposits,local factors played significant roles in some of the deposits.Therefore,phosphorites formed in marine conditions with open circulation within the tropical zone.While lush growth of rainforest covers in the tropical belt facilitated the formation of coastal lignite.
其他文献
一个眼睛看不见的人并不在乎自己错过了世间绚丽的风景,她的心里拥有最丰富的色彩和期待,然而最可悲的是她生活在一个父权夫权主宰的世界里却无力挣脱,只能等待命运的枷锁将
电影《黑白往事》以黑白为题,讲述一段盲女的爱情故事。活在黑暗世界的盲女,虽然无法看到世界的五彩,也因此具有一颗纯洁无瑕的心。黑的世界,白的内心。用她的单纯体悟着人世
订妥机票的刹那,不禁有些怅惘。我茫然地望着窗外,纷飞的红叶、黄叶,不知什么时候铺满了小径。又是一度秋意浓,此时远行,似乎另有一番滋味于心田。一位诗人朋友对我说,天涯行
期刊
于首映现场观看了由山东章丘作家牛余和原创并亲自担任编剧拍摄的电影《黑白往事》,心中颇多感悟。这是一部小成本制作的电视电影,与如今动辄投资上千万的“大片”相比自然是
讲述了一个发生在长工的儿子与自家老爷瞎眼女儿之间的爱情故事,从盲女的娘家到盲女的夫家,长工一路追随,做着无怨的下人,始终揣着对那双看不到颜色却盈满温柔的眼睛;从有家
请下载后查看,本文暂不支持在线获取查看简介。 Please download to view, this article does not support online access to view profile.
期刊
每年体检中都有不少人查出脂肪肝.目前临床上还没有治疗脂肪肝的特效药,建议患者注意控制饮食,多做运动,3个月后再做B超复查.rn脂肪肝就好比代谢综合征的前奏.得了脂肪肝的人
期刊
请下载后查看,本文暂不支持在线获取查看简介。 Please download to view, this article does not support online access to view profile.
期刊
二十世纪以来全球银行业经历的三次并购浪潮进行回顾,每次并购都有其特点和趋势。而德意志银行和汇丰银行是两家非常成功地利用跨国并购而迅速成为世界一流的全能型商业银行。
随着国内经济增速的放缓,加之制造业产能过剩,市场的竞争日益激烈,低成本、高效率、个性化、多样性等客户需求已成为商家的追求目标,本文通过介绍精益生产产生的历史背景及在制造业领域的应用意义,阐述在当前行业背景下推广精益生产的必要性。文章首先介绍了精益生产的关键理念概念及相关指导思想,即精益生产就是要消除浪费、降低成本,着重于整体效益的提升,然后介绍了常用的精益生产理论工具。其次,文章通过对FT公司的现