摘要
对鄂尔多斯盆地西南部陇东地区中上三叠统微体古生物进行了分析,在延长组长7段发现极其丰富的以光面球藻为主的疑源类组合。与古生代以前光面球藻来源于海生单细胞浮游藻类不同,延长组光面藻可能来源于湖相淡水宏观藻类,这些化石可能是大型红藻或绿藻类的孢子体。疑源类分布的高丰度层位长73—长72段恰好是本地区的主要油源岩层。疑源类不仅是源岩中藻类体和无定形体的主要组成部分,而且热解指数也显示出,随疑源类丰度的升高,源岩生烃能力逐渐增强。这些特征均表明疑源类是鄂尔多斯盆地三叠系延长组湖相优质烃源岩形成的重要母质。
The microfossil analysis of the samples from the Middle and Upper Triassic in eastern Gansu Province was made. The extremely abundant acritarchs assemblage mainly consisting of Leiosphaeridia was discovered in Chang 7 Member of Yanchang Formation in southwestern Ordos Basin. Leiosphaeridia discovered from the Yanchang Formation might root in the lacustrine macroscopic algae, which may be the sporophyte of large-scale red algae and/or chlorophytes. Whereas the Proterozoic and Paleozoic Leiosphaeridia is commonly thought as the marine unicellular phytoplankton. The strata of high abundance acritarchs accorded with the distribution of the main source rock in Chang 7-3 and Chang 7-2 members of Yanchang Formation in eastern Gansu Province. The acritarchs is the important component of alginite and amorphous mass. The pyrolytic indexes show that hydrocarbon potential gradually boosts up with the increase of acritarchs abundance. The lacustrine acritarch is the important biologic source of high-quality source rock of the Yanchang Formation in Ordos Basin.
出处
《石油学报》
EI
CAS
CSCD
北大核心
2007年第2期40-43,48,共5页
Acta Petrolei Sinica
基金
中国科学院"西部之光"人才培养计划项目
甘肃省中青年科技基金项目(AC2002-404-01)联合资助
关键词
鄂尔多斯盆地
西峰油田
三叠系
延长组
疑源类
烃源岩
Ordos Basin
Xifeng Oilfield
Triassic
Yanchang Formation
acritarchs
hydrocarbon source rock
