华蓥山地区二叠纪生物礁顶部钙结壳的岩石学特征及成因探讨

华蓥山地区上二叠统长兴阶生物礁顶部普遍存在一套数米至十余米厚的钙结壳．含有钙结壳中常见的渗滤豆石、钙质结核、蜂窝状构造、根模、钙化细菌丝体、花瓣构造、微型钟乳石等典型组构，并伴有变形构造、溶蚀构造和角砾化等现象。这套钙结壳的发现对研究华南二、三叠纪之交的古气候，古地理和沉积发育史具有重要意义，本文主要描述钙结壳的岩石学特征，并简要讨论了本地区钙结壳的成因。

PETROLOGY AND ORIGIN OF THE CALCAREOUS CRUSTS CAPPING THE PERMIAN REEFS IN HUAYING MOUNTAINS, SICHUAN, CHINA

Calcareous crusts capping the uppermost Permian reefs have been discovered in Hua-ying mountains.The calcareous crusts are several meters in thickness and mainly coposed of hard pans, spot calcretes,bedded calcretes and domal calcretes,The calcareous crusts include a variety of typical textures,such as plsoliths,calcareous nodules,alveolar textures,rhizoliths,calcified fila-ments,Microcodium and microstalactites,which have been commonly found in calcretes. Deforma-tion,solution and brecciation structures are also popular.The calcareous crusts are very important in exploring the paleoclimite,paleogeography, and Sedimentological evolution in the transitional period of Permian and Triassic,This paper deals with the petrological characters of the caleareous crusts and brierly discusses their origin.