砂岩稀土元素地球化学特征在沉积物源区分析中的应用——以中国东北漠河盆地中侏罗统为例

详细取样分析显示，漠河盆地中侏罗统砂岩具有如下稀土元素地球化学特征:(1)绣峰组、额木尔河组和开库康组砂岩的稀土元素球粒陨石标准化配分模式均表现出轻稀土富集、重稀土亏损但具变化平缓和明显的Eu负异常特征；二十二站组虽呈现轻稀土富集、重稀土亏损但变化平缓的特征，但没有明显的Eu负异常特征，反映了砂岩形成时的物源有差别。(2)漠河盆地中侏罗统的物源主要来自于上地壳长英质源区，源岩可能为花岗岩、变质岩和沉积岩的混合；但二十二站组和额木尔河组时期还可能有来自下地壳或幔源的深部物质（基性岩）加入导致物源发生了变化。(3)漠河盆地中侏罗统物源区的构造背景为活动大陆边缘的岛弧环境。(4)Ce/Ce*和Ceanom指数显示漠河盆地中侏罗统的古环境为还原环境，对油气生成十分有利。

Application of REE Geochemical Characteristics of Sandstone to Study on Provenance:a case from the Middle Jurassic of Mohe Basin in Northeast China

Based on analyses of the samples in detail, the REE geochemical characteristics of the Middle Jurassic sandstone in Mohe Basin are described. The results indicate: (1)The LREE content obviously enriches compared with the HREE content and with negative Eu anomalies shown in the chondrite aerolite standard pattern of sandstone of Xiu Feng, E Muerhe and Kai Kukang Formations. However, Er Shierzhan Formation is obviously different frorm them. Little negative Eu anomalies is shown in the chondrite aerolite standard pattern of sandstone of Er Shierzhan Formation, which reflects the sandstone is from different provenance. (2) The provenance of the Middle Jurassic Sandstone in Mohe Basin may be felsic rocks of upper crust, including granites, metamorphic rocks and sediments. During the deposition of the Er Shierzhan Formation and E Muerhe Formation, some materials may be from the deep lower crust or mantle and leads to the great change of Provenance. (3)The tectonic settings of provenances of the Middle Jurassic Sandstone in Mohe Basin is the island arc of the margin of active continent.(4) The Ce/Ce* and Ceanom indexes indicate that the palaeoenvironment of the Middle Jurassic in Mohe Basin was a reduction environment and is profitable for the oil and gas formation. 