【摘要】 分布于山东省鲁西地区的济宁群是全隐伏浅变质海相火山—沉积地层,主要岩性组合为:绿泥绢云千枚岩、变凝灰质砂岩、千枚状粉砂岩、变长石砂岩、炭质(绿泥)绢云千枚岩、方解绢云千枚岩、石英绢云凝灰质千枚岩、方解磁铁石英岩、千枚状变质砂岩、变英安岩等。下部为变火山碎屑岩系,以出现变火山碎屑岩(含熔岩)和粒度相对粗的正常碎屑岩为特点,称为翟村组;中部为含铁岩系,以出现较多方解磁铁石英岩为特点,称为颜店组;上部为千枚岩系,以夹火山—正常细碎屑岩和炭质含量不等的千枚岩为特点,称为洪福寺组。地层变质程度为低绿片岩相,经历了较强烈的褶皱变形和韧性剪切变形作用改造。地球化学特征指示,济宁群中碎屑岩的源岩为鲁西TTG岩系,地层总体为裂谷环境还原条件下的热水沉积组合。含铁岩系具苏必利尔湖型BIF铁矿特征。更多还原

【Abstract】 The Jining Group in western Shandong Province consists of buried metamorphic marine volcanic and sedimentary strata.Its main rock types include chlorite sericite phyllite,tuffaceous metasandstone,phyllitic siltstone,metamorphosed feldspathic sandstone,carbonaceous sericite phyllite,calcite-bearing sericite phyllite,tuffaceous sericite phyllite,calcite-bearing magnetite quartzite,phyllitic metamorphic sandstone,and metamorphic dacite.The Zhaicun Formation of the lower Jining Group is composed of metamorphosed volcaniclastic rocks,including abundant metamorphosed volcaniclastic rocks and relatively coarse-grained clastic rocks.The Yandian Formation of the middle Jining Group is composed of iron formations with calcite-bearing magnetite quartzite.The Hongfusi Formation of the upper Jining Group is composed of a phyllite series containing volcanic and fine-grained clastic rocks as well as carbonaceous phyllite.The Jining Group experienced low greenschist facies metamorphism,folding,and ductile shearing deformation.Simple sphaeromorphic acritarchs have been found in the Jining Group.The iron formations in the Jining Group are similar to the Paleoproterozoic Lake Superior-type BIF.The Jining Group is probably Paleoproterozoic in age.Geochemical data indicate that clastic rocks in the Jining Group were likely sourced from TTG rocks in western Shandong Province and that the Jining Group was deposited in a hydrothermally influenced rift basin.更多还原