摘要
在对Sc、Co、Ni、Ga、Rb、Sr、Mo、Ba等微量元素进行电感耦合等离子体质谱(ICP-MS)测试和对泥岩粘土矿物进行X射线衍射相对定量分析的基础上,结合骨架砂岩岩石薄片镜下观察结果,采用Sr-Rb-Ba-Sc多元素标准化图解,分析了济阳坳陷石炭二叠系暗色泥岩微量元素赋存特征及其所指示的海陆沉积相变化、火山事件、物源等方面的地质意义。研究结果表明:(1)济阳坳陷暗色泥岩微量元素含量普遍比华北地台同时期沉积物高(Ba除外)。(2)济阳坳陷本溪组和太原组下部发育海相沉积以及上石盒子组曾发生数次规模较大的海侵,表现为在Sr-Rb-Ba-Sc标准化图解中Sr上扬,或Rb-Ba-Sc近似呈直线;局限台地相沉积可能造成其上部相邻地层泥岩中Rb、Sr发生异常。(3)在济阳坳陷石炭二叠系骨架砂岩岩石薄片中观察到自形石英、港湾状石英、聚片双晶长石、保存较好的挠曲状云母,推测石炭二叠系受到多次火山作用影响;Sr-Rb-Ba-Sc标准化图解中Rb异常可能揭示火山作用的影响,而Rb异常的泥岩样品通常高岭石含量非常高(>70%),且伊利石含量非常低(<5%)。(4)Rb-Ba-Sc标准化图解显示济阳坳陷石炭二叠系物源区可能是华北地台北部的古老岩体,母岩岩浆来自上地壳。
Based on elemental analysis of Sc, Co, Ni, Ga, Rb, Sr, Mo and Ba using ICP-MS, and clay mineral relative quantification analysis using X-Ray diffraction instrument, combined with researches on thin sections of sandstone under the microscope, trace elemental characteristics and their geological significances on sedimentary facies, volcanic event and provenance were analyzed by the Sr-Rb-Ba-Sc multi-element diagrams. The results showed that contents of most trace elements （except Ba） in Permo-Carboniferous dark mudstone in Jiyang Depression were slightly higher than those in synchronous sediment on North China Platform. Marine sedimentary facies developed in Benxi Formation, the lower part of Taiyuan Formation and Shangshihezi Formation, which were characterized by a high Sr index or nearly a straight line on the Rb-Ba-Sc diagram. Marine mudstone sediments may have a relative high Rb and low Sr contents under the influence of lower neighboring restricted platform sediments. Rb anomalies the diagrams maybe indicate volcanic events which were affirmed by idiomorphic quartz crystals, embayed quartz crystals, polysynthetic twin feldspar and twisty kaolinite content （〉 70% ） and a low illite content （〈 5% mica. Samples with Rb anomalies usually had a high ） meanwhile. The Rb-Ba-Sc diagrams showed the provenance of Permo-Carboniferous in Jiyang Depression was the oldland in northern North China Platform, and the parent material was derived from the upper crust, which were confirmed by fruits of other researches.
出处
《地球化学》
CAS
CSCD
北大核心
2009年第1期57-67,共11页
Geochimica
基金
国家油气专项(XQ200403-03)
