关键词: 松辽盆地, 古中央隆起带, 特殊岩性, 基底, 网状裂缝, XRF元素分析

Abstract: The central uplift belt(north) of Songliao basin has good natural gas accumulation conditions and is one of the important areas of natural gas rick exploration in recent years. Due to the lack of drilled wells and thin drilled strata, the special lithology and stratigraphic characteristics of the area are currently unknown. To this end, based on the microscope observation of cuttings, XRF element analysis and cuttings thin section analysis and other data of drilled wells, on the basis of a large amount of data analysis and geological research, the lithologic characteristics of central paleo-uplift belt(north) in Songliao basin was summarized. A couple of understandings were drawn. First, the basement structure of Songliao basin is complex, and complex lithology was formed after multistage tectonic movement. Three groups of basement rock sequence were determined, which are metamorphic glutenite+slate+phyllite+schist, granite+diorite, and fragmentation+mylonization granite. Second, the basement of central paleo-uplift belt has been exposed to the surface for a long time. Map cracking is developed on the top weathering crust with obvious oxidation characteristics and weathering index indication. Third, the element composition is highly reliable in determining country rock component of the metamorphic rock. Guiding the site through these understandings can effectively enhance the timeliness and accuracy of lithologic discrimination on site and provide important geological data for the rolling exploration and research of the basement of central paleo-uplift belt in Songliao basin.

Key words: Songliao basin, central paleo-uplift belt, special lithology, basement, map cracking, XRF element analysis