豫西苗岭统馒头组二段皱饰构造与遗迹化石共生特征*

埃迪卡拉纪以来,微生物与后生动物之间呈此消彼长的关系,但在寒武纪苗岭世却出现了微生物成因沉积构造和后生动物扰动构造短暂共存的现象。笔者在豫西馒头组二段下部识别出包括皱饰构造与微生物席裂构造在内的2种微生物成因沉积构造,对皱饰构造与遗迹化石的共生关系进行了分类,建立了席上足辙迹(Monomorphichnus henanensis)与牧食迹(Jinningichnus badaowanensis)、席下水平漫游迹(Planolites montanus)、席下深层泥岩中生物扰动共3种微生物席与后生动物的共生模式和生态演化模型。上述研究表明,具有特殊环境耐受性的“机会主义”动物在食物来源较为宽松的潮坪环境中与微生物席共存,这种微生物席与后生动物短暂而“和谐”的共存关系不仅延续了埃迪卡拉纪双方的部分共生特征,且在以混合底为主导的显生宙生态环境中得到了进一步变化与发展。

Symbiotic characteristics of wrinkle structure and trace fossils in the Second Member of Miaolingian Mantou Formation in western Henan

Since the Ediacaran period,the microbes and metazoan were interacted,but microbial induced sedimentary structures(MISS)and metazoan bioturbation structures coexisted temporarily in the Cambrian Miaoling age. In this paper,two types of microbially induced sedimentary structures,including wrinkle structures and microbial mat-crack structures,are identified in the lower part of the Second Member of the Mantou Formation in western Henan Province. The symbiotic relationship between MISS and trace fossils was classified,and three models of the symbiotic relationship between the wrinkle structures and metazoans and ecological evolution model of microbial mat and metazoan were established, including the trackways(Monomorphichnus henanensis)and the grazing trace(Jinningichnus badaowanensis)on the microbial mat, Planolites montanus under microbial mat, and the burrows in mudstone substrate. It showed that some organisms with special environmental tolerance coexisted with microbial mats in the tidal environment with relatively sufficient food sources,revealing the short period of harmonious coexistence relationship between microbial mat and metazoans not only continued the partial symbiotic characteristics during the Ediacaran,but also developed in the mixground-dominated Phanerozoic ecological environment.