引言虽然 Stuart(1969)曾在一篇关于澳大利亚南部布兰切角组的论文中提到过常被当作火山起源证据的斜发沸石,但他并不认为布兰切角组属火山起源。详细的化学和矿物学研究(Jones 和 Fitzgerald,1984,1986)证明,该组沉积的非生物成因部分大多数(即使非全部)都是在水体中沉淀下来的火山灰堆积物。成为该组大部分沉积之特征的硅化作用,乃是继火山灰蚀变和硅质的小规模迁移后 CT-蛋 INTRODUCTION Although Stuart (1969) referred to clinoptilolite, which has often been used as evidence of volcanic origin, in a paper on the Cape Cuttison Formation in southern Australia, he does not consider the Cretan cut-off to be of volcanic origin. Detailed chemical and mineralogical studies (Jones and Fitzgerald, 1984, 1986) demonstrate that most, if not all, of the non-biogenic parts of this sediment are volcanic ash deposits that have settled in the water. The silicification that has been the hallmark of most of the sediments in this group is CT-egg after volcanic ash alteration and siliceous small-scale migration