黑龙江七星河含煤盆地古近纪-新近纪沉积相及层序地层特征

Paleogene-Neogene Sedimentary Facies and Sequence Stratigraphic Characteristics in Qixinghe Coal-bearing Basin, Heilongjiang

黑龙江省东部七星河盆地是一新生代聚煤盆地,其含煤地层为古近系宝泉岭组、新近系富锦组。宝泉岭组由各级砂岩、泥岩、炭质泥岩以及褐煤组成,发育滨浅湖相、深-半深湖相、三角洲平原相,属于湖泊沉积体系、三角洲沉积体系。富锦组主要由泥岩、粉砂岩、中砂岩、含砾粗砂岩及煤层、炭质泥岩、硅藻岩组成,发育滨浅湖相、扇三角洲平原相,分别属于湖泊沉积体系和扇三角洲沉积体系。层序SI相当于宝泉岭组,发育低位体系域、湖侵体系域和高位体系域,煤层主要发育高位体系域中后期,成煤环境以滨浅湖淤积沼泽为主。层序SII相当于富锦组,主要发育湖侵体系域、高位体系域,局部地区发育低位体系域,煤层亦主要发育高位体系域中后期,成煤环境以扇三角洲淤积沼泽和滨浅湖淤积沼泽为主。层序SI、SII的高位体系域中后期,盆地基底沉降速率和物源供给处于相对平衡状态,主要发育了扇三角洲淤积沼泽、滨浅湖和滨浅湖淤积沼泽环境,发育可采煤层。

The Qixinghe Basin in eastern Heilongjiang is a Cenozoic coal accumulation basin. Its coal-bearing strata belong to Paleogene Baoquanling Formation and Neogene Fujin Formation. The Baoquanling Formation is comprised of sihstone, sandstone of various grain sizes, mudstone, carbonaceous mudstone and lignite; developed littoral-shallow lacustrine facies, deep-semideep lacustrine facies, delta plain facies belong to lake sedimentary system, lake delta sedimentary system. The Fujin Formation is comprised of mudstone, sihstone, medium-grained sandstone, pebbly coarse-grained sandstone, coal, carbonaceous mudstone and diatomite; developed littoral-shallow lacustrine facies, fan delta plain facies, belong to lake sedimentary system and fan delta sedimentary system respectively. Sequence SI is corresponding to Baoquanling Formation; developed lowstand system tract, lacustrine transgressive system tract and highstand system tract. Coal seams were mainly developed during middle to late stages of highstand system tract; coal-forming environment was mainly littoral-shallow lacustrine silting bog. Sequence SII is corresponding to Fujin Formation; mainly developed lacustrine transgressive system tract, highstand system tract, locally lowstand system tract. Also, coal seams were mainly developed during middle to late stages of highstand system tract; coal-forming environment was mainly fan delta silting bog and littoral-shallow lacustrine silting bog. During sequences SI, SII middle to late stages of highstand system tract, basin basement settlement rate and sediment supply were in a relatively balanced state, mainly developed fan delta silting bog, in littoral-shallow lacustrine and littoral-shallow lacustrine silting bog environments have developed mineable coal seams.