惠民凹陷古近系风暴沉积研究

利用岩心观察、薄片鉴定、粒度分析及测井解释等方法,对惠民凹陷古近系风暴沉积进行了研究。根据风暴岩的垂向序列类型、沉积构造特点和原地沉积物特征等总结出9种风暴岩序列和原地风暴岩、A型近源风暴岩、B型近源风暴岩和远源风暴岩等4种沉积模式,并总结了风暴岩的分布规律。结果表明,该凹陷风暴沉积岩石类型丰富,包括各类碎屑岩、生物灰岩和火山碎屑岩。粒度分布具有“高斜多跳-悬式”、多段式和“高斜-段式”等多种样式,沉积构造发育渠模、冲刷面、截切等底层面侵蚀构造和递变层理、块状层理、丘状层理、洼状层理、平行层理等构造,还发育有波痕和各种同生变形构造、生物逃逸构造等。粒度分布和沉积构造反映出研究区兼有重力流和牵引流的水动力机制。在剖面上,风暴沉积与非风暴沉积交互出现,发育程度与层位、古地形、古水深、构造位置及碎屑供给特征等条件有关;在平面上,风暴岩被非风暴岩所包围,向陆、向浅水方向一般为（扇）三角洲、滩坝沉积体,向盆地方向变为浊积岩或半深湖、深湖泥页岩。

Study of tempestite sedimentary of Paleogene in Huimin depression

By means of core observation,thin-section analysis,granularity analysis and log analysis,the tempestite sedimentary of Paleogene in Huimin depression was studied.Nine kinds of tempestite sequences and four sedimentary models such as autochthonous coarse grain rocks,near source tempestite A,near source tempestite B and distal tempestite were summarized according to vertical sequence types, structures and sediment characters.The distribution rule of tempestite was also summarized.The results indicate that the tempestite in the area has lots of rock types including clastic rocks,bioclastic limestones and volcaniclastic rocks.The cumulative probability plots have "high slope-multi-bouncing population-1 suspension population" pattern,multi-segments pattern and "high slope 1 segment" pattern.The sedimentary structures include gutter cast,surface of scour, cut structure,graded bed,massive bedding,hummocky cross stratification(HCS),parallel bedding,ripples,contemporaneous deformation and Fugichnia.The grains distribution and sedimentary structures show that the transportation medium is characterized by tractive current and gravity flow synchronously.The tempestite and non-tempestite occur alternately in vertical section.The development of tempestite is related to stratum,ancient landform and water depth,tectonic location and clast supply.The tempestite is encircled by non-tempestite in horizontal section.The tempestite became(fan) delta,beach & bar toward the shallow water,and became turbidites or(half) deep lake clay stone towards basin.