摘要
在我国前陆盆地研究中 ,谨防泛前陆盆地化 ,进一步准确理解其概念和涵义 ,了解国外典型前陆盆地的特征是必要的。同时 ,应加强对我国中西部“中国型盆地”的研究。贺兰山山脉主体部分主要由三叠侏罗纪沉积地层组成。西到阿拉善地块 ,东至鄂尔多斯盆地 ,三叠侏罗纪地层单元为纸坊组、延长群、延安组、直罗组和安定组。贺兰山隆升的时间应在中生代末期—新生代 ;地层序列表现出的特征是水由浅变深 ;岩屑成分和古流向玫瑰花图显示其物源来自北部贺兰山群 ;表现盆地形状和深度的地层等厚线也不是终止于山脉东侧 ,而是一直延续到了阿拉善地块上 ;主要逆冲断裂的逆冲方向在东侧是向西 ,在西侧是向东。以上特征均表明它与前陆盆地的特征和标志不符 ,鄂尔多斯盆地西缘 。
In the foreland basin researches of China, the deep and accurate understanding of the concept and meaning of the foreland basins and the comprehension of the features of the typical foreland basins abroad are absolutely necessary so as to prevent the excessive broadening of the concept of the foreland basin. In addition, the research on “Sino-type basin' in central western China should be strengthened. The main part of the Helan Mountain is composed of Triassic-Jurassic strata, which comprise from west Alxa massif to east Ordos Basin Zhifang-Yanchang Group, Yan'an Formation, Zhiluo Formation and Anding Formation. The Helanshan Mountain lifting might have taken place at the end of Mesozoic-Cenozoic period. The stratigraphic sequence is characterized by the increasing depth of water. The lithic fragment components and the rose diagram of paleocurrent show that the sediments must have come from Helanshan Group in the north. The stratigraphic isopaches which describe the shape of the basin and the depth of water extend into Alxa massif instead of being ended on the eastern side of the Helan Mountain. The thrusting direction of the main thrust faults is westward on the eastern side of the mountain and eastward on the western side. The above-mentioned features are not consistent with the characteristics and criteria of the foreland basin. The western edge of Ordos Basin, at least the central northern part of the western edge, is not a foreland basin.
出处
《岩石矿物学杂志》
CAS
CSCD
北大核心
2004年第4期318-326,共9页
Acta Petrologica et Mineralogica
基金
国家重点基础研究发展计划 (973)资助项目 (2 0 0 3CB2 146 0 1)
关键词
鄂尔多斯盆地
前陆盆地
贺兰山
阿拉善地块
地层序列
地层等厚线
Ordos Basin
foreland basin
Helan Mountain
Alxa massif
stratigraphic sequence
stratigraphic isopach
