摘要
福建下白垩统坂头组主要为一套温暖潮湿的湖泊相、河流相碎屑沉积,化石丰富,黑色页岩相对发育。以政和—大埔断裂为界,坂头组在其西、东部差异明显,目前有关坂头组的诸多问题亟待深入研究。本文通过野外地质调查、室内研究等,认为早白垩世福建一带为火山较活跃的岛弧型沉积,断陷盆地发育;坂头组沉积时代为早白垩世阿普第期;早白垩世福建等地断陷湖盆未曾发生持续性、大规模的快速下降,碎屑沉积厚度不大;坂头组不甚明晰的阶段性沉积特征,揭示出受控于古太平洋板块与欧亚大陆相互作用,也具有一定的期次性;坂头期及其后的火山作用强烈,对有机质以及烃的富集影响明显。如果台湾海峡一带也发育坂头组或与其相当的岩层,或发育有时代较晚的黑色页岩、砂岩,且具有一定的沉积厚度、规模,将具有重要的石油地质意义。应继续加强坂头组地质研究以及其与上下层系的石油地质条件配置研究,加强对于台湾海峡白垩系、古近系和新近系的石油地质研究,也应加强后期岩浆活动的改造作用研究。
The Early Cretaceous Bantou Formation in Fujian Province is of river and lacustrine facies of fragmental sediments with well-developed black shales.The lake and swamp were widely distributed,which could be assigned to mild mid-latitude climate geographical environment.It has rich and different kinds of fossils.The Zhenghe-Dabu fault zone is a boundary,with which Fujian continent can be easily divided into west and east parts.There are obvious differences in appearance and characteristics of Bantou Formation in these two parts.There are some problems concerning Bantou Formation which deserve further studies.In this paper,knowledge was obtained through scientific investigation by the combination of field survey with in-door analysis.The sedimentary period of Bantou Formation belonged to Aptian Stage in an active island arc belt in Early Cretaceous.Graden basins were extensively developed,which subsided at the early stage and was faulted at the late stage.The tectonic background of Bantou Formation resulted from the interaction between palaeo-Pacific plate and Eurasian plate,with the crust thickness subtracted probably in partial areas.There were no continuous large scale subsidence of graden basin in Early Cretaceous in Fujian and Taiwan Strait,and the source rocks and reservoirs with considerable thickening could be hardly formed.Oil and gas potential can hardly be delineated without the knowledge of thickened detrital deposition and good allocations.As thermal events were violent volcanic movements in Fujian and Taiwan Strait from Cretaceous to Cenozoic,they might have strongly affected the transformation and migratory concentration of organic materials at the late stage of Early Cretaceous.The understanding obtained by the authors is of great significance,showing that the investigation of tectonic,lithofacies and palaeogeographic factors is very important in oil and gas exploration in Bantou Formation.
出处
《中国地质》
CAS
CSCD
北大核心
2011年第5期1220-1231,共12页
Geology in China
基金
国家重大科技专项43“全国油气基础地质研究与编图”(2008ZX05043-005)
国家重点项目“中国地质构造区划与区域地质调查综合集成”(1212010811033)资助
关键词
福建坂头组
沉积特征
断陷盆地
构造
台湾海峡
油气资源
Bantou Formation in Fujian
sedimentary characteristics
terrestrial fault basin
tectonic
Taiwan Strait
oil and gas resources