在湖北保康马桥地区，新元古代神农架群石家冲组产出一套奇异的叠层石，凝块石和叠层石－凝块石联合体。其中叠层石具类似于食草和钻孔动物破坏的疤痕，通过对上述构造形态和特征分析，这些构造可能与后生动物的活动有关，但也不排除它们是非生物成因的可能。这些后生动物似乎已显示高度发育的行为。当前的资料表明，在凝块石构造与食草和钻孔动物生态效应之间似乎存在着一种紧密的联系，在生物进化史上，寒武纪生命大爆发似乎仅是一

The Neoproterozoic Shijiachong Formation contai ns a well preserved suite of aberrant stromatolites with graze like and burrow like scar structures,thrombolite structures and stromatolite thrombolite str ucture unities.Analysis of their morphologies and features leads to the conclusi on that these structures might have been in connection with metazoan activity, bu t the possibility of their abiotic origin can not be ruled out.As a guess these metazoans seem already to show highly developed behaviour.A close relationship m ight exist between the thrombolite structure and ecological effects of grazing a nd burrowing metazoans.The Cambrian life explosion seems to be more apparent tha n real in evolutionary history because older metazoans in Neoproterozoic were no t capable of preservation due to lack of hard parts and suitable embedding sedim ents.

Q915.63

中国科学院资助项目;49372073;