内蒙古固阳渣尔泰山群增隆昌组台前斜坡碳酸盐角砾岩的成因

内蒙古固阳渣尔泰山群增隆昌组晚期沉积环境演化为碳酸盐岩台地。重点研究了台前斜坡碳酸盐角砾岩的岩性、岩相和相序特征 ,识别出重力滑动、浊流和风暴重力流成因的角砾岩 ,探讨了不同成因的角砾岩与海平面变化的响应关系。研究表明 ,角砾岩主要形成于海平面的上升速率减慢或最大静止期 ,此时台地碳酸盐岩产率过剩 ,大量的碳酸盐岩由地震、重力、风暴流带入斜坡和坡底 ,形成异地角砾岩。

CARBONATE CALCIRUDITE GENESIS OF THE ZENGLONGCHANG FORMATION OF ZHAERTAISHAN GROUP IN THE GUYANG DISTRICT,INNER MONGOLIA

Later Zenglongchang Formation of Zhaertaishan Group in the Guyang district of Inner Mongolia belongs to the rimmed shelves carbonate platform . The four paleogeography units of back-platform basin, carbonate platform, fore-platform slope and fore-platform shelve basin can be divided from land to sea. The research is mainly done on lithology,lithofacies and facies sequence of calcirudite at fore-platform slope . The calcirudites originated by gravity sliding, turbidity flow and wind storm gravity flow have been recognized and their responds to sea-level change have been discussed. The study shows that calcirudites were mainly formed during sea-level rise and stillstand. When carbonate production exceeded the rate or creation of accommodation space ,carbonate was shed off the platform top to the slope and basin by storm, gravity and earthquake, forming allochthonous calcirudites.