辽宁新元古界桥头组砂岩地球化学特征及其沉积背景  

Geochemical characteristics of sandstone and sedimentary background of Neoproterozoic Qiaotou Formation in Liaoning

作　　者：吴子杰 张国仁 邱隆伟[2] 王海鹏 仲米山 高福亮 潘玉啟 骆念岗 WU Zijie;ZHANG Guoren;QIU Longwei;WANG Haipeng;ZHONG Mishan;GAO Fuliang;PAN Yuqi;LUO Niangang(Liaoning Institute of Geological Exploration Co.,Ltd,Dalian 116100,Liaoning,China;School of Geosciences,China University of Petroleum(East China),Qingdao 266580,Shandong,China;Fossil Protection Technology Innovation Center of Liaoning Geological Exploration and Mineral Group,Dalian 116100,Liaoning,China;College of Earth Sciences,Changchun 130061,Jilin,China;Shenyang University of Technology,Shenyang 110870,Liaoning,China)

机构地区：[1]辽宁省地质勘查院有限责任公司,辽宁大连116100 [2]中国石油大学(华东)地球科学与技术学院,山东青岛266580 [3]辽宁地矿集团化石保护科技创新中心,辽宁大连116100 [4]吉林大学地球科学学院,吉林长春130061 [5]沈阳工业大学,辽宁沈阳110870

出　　处：《中国地质》2024年第5期1714-1726,共13页Geology in China

基　　金：辽宁省地质勘探矿业集团项目(2017−03、2016−01);中国地质调查局项目(1212011120734);辽宁省地质矿产局(1994−15)联合资助。

摘　　要：【研究目的】辽宁新元古界桥头组的沉积时代仍未准确厘定,导致关于其沉积背景特别是古气候的讨论充满争议,利用岩石地球化学特征等方法对其沉积背景进行讨论具有重要意义。【研究方法】通过桥头组砂岩的岩石地球化学资料,分析CaO/(CaO+Fe)、Sr/Ba、V/(Ni+V)等元素比值以及CIA、ICV、C_(eanom)等参数,重建古风化气候条件、古盐度及古氧化−还原条件。【研究结果】桥头组砂岩样品的CIA值多数位于温暖潮湿区域,而ICV值则多数位于寒冷干燥区域;样品的CaO/(CaO+Fe)、Sr/Ba值绝大多数落入中咸水区域,少量在微咸水区域;砂岩样品的V/(Ni+V)和C_(eanom)值则处于还原区域,少量在氧化区域。【结论】桥头组并非沉积于南华纪,其沉积期总体为中咸水的缺氧还原环境、气候温暖潮湿。This paper is the result of geological survey engineering.[Objective]The sedimentary period of the Qiaotou Formation in Liaoning is still not accurately determined,which leads to controversial discussions about its depositional background,especially the palaeoclimate.It is of great significance to discuss its depositional background by using petrogeochemical characteristics and other methods.[Methods]We reconstructed the palaeo−weathering climate conditions,palaeo−salinity and palaeo−oxidation−reduction conditions by analysing the elemental ratios of CaO/(CaO+Fe),Sr/Ba,and V/(Ni+V),as well as the parameters of CIA,ICV,and C_(eanom)from the petrogeochemical data of the sandstones of the Qiaotou Formation.[Results]Most of the CIA values of the sandstone samples from the Qiaotou Formation are located in the warm and humid region,while most of the ICV values are located in the cold and dry region.Most of the CaO/(CaO+Fe)and Sr/Ba values of the samples fall into the medium saline region,and a small amount is in the slightly saline region.V/(Ni+V)and C_(eanom)values of sandstone samples are in the reduced region,and a small amount is in the oxidised region.[Conclusions]The Qiaotou Formation was not deposited in the Nanhua Period,and its depositional period was generally in an anoxic reducing environment with medium saline water and a warm and humid climate.

关 键 词：砂岩 地球化学 沉积背景 古气候 古盐度 古氧化—还原条件 桥头组 地质调查工程 辽宁 

分 类 号：P532[天文地球—古生物学与地层学]