新疆和田杜瓦地区葡萄藻化石的发现及其意义

Discovery and Significance of Botrvococcus in Duwa Area of Hetian, Xinjiang

新疆和田杜瓦地区出露的上二叠统一下三叠统,暗色泥岩较厚,其沉积中心在北部覆盖区,物源在杜瓦断裂以南的露头区。覆盖区的沉积环境水深要大于露头区,暗色泥岩的厚度及分布范围加大。尽管露头样品的地球化学生烃指标不高,但在多个层段、多条剖面发现有葡萄藻化石,有些还特别富集,平面上葡萄藻化石的分布相对稳定和广泛,这套暗色泥岩应该具备较强的生烃能力,是新疆和田地区烃源岩评价的重要层段。

The Upper Permian-Lower Triassic outcrops in Duwa area of Helian, Xinjiang are dominated by thick dark shale. The sedimentary center is at north areal coverage, the source area is at the outcrop area in south of Duwa faulting. The former has deeper sedimentary environment, than the latter, so its dark shale is thickened and distributed range is enlarged. The geochemical indicators for hydrocarbon generation from outcrop samples are not high, but there exist Botryococcus fossils in many intervals and sections, which are rich in some horizons, with relative stable and extensive distribution in plane. It means that the dark shale should be of higher capability or potential for hydrocarbon generation, and will be as important strata for hydrocarbon source rock evaluation in Hetian region, Xinjiang.