The depositional character of zhuxiang formation in the basin reads as follows : a series of nne alluvial fan were formed along the fault . the half - deep lake to deep lake faces appeared by west side of the fault , towards the west the saucer lake faces , shore deposit and flood plain face appeared in proper order . the depositional center of lower cretaceous was formed in eastern part of the basin , and the depositional depth was pinch - out and thinning out from the east to the west 盆地内下白垩统朱巷组沉积特征表现为：沿郯庐断裂带呈北北东向广泛发育了冲积扇体系，从近断裂带西侧出现的半深湖-深湖相，向西依次为滨浅湖相到泛滥平原相的规律性分布，沉积厚度由东向西尖灭、超覆，构成了明显的东断西超的盆地构造格局，表明下白垩统的沉积中心依然位于盆地东部。
Sedimentary facies consist of fan delta , delta , nearshore submarine fan , sublacustrine fan , littoral - shallow lake beach and bar , as well as littoral - shallow lake , and semideep - deep lake facies and subfacies , of which the preferred sedimentary facies include delta , fan delta front , sublacustrine fan , midfan and outer fan of the nearshore submarine fan , and beach - bar facies developed in the littoral - shallow lake 综合考虑物源特徵、沉积环境、沉积体系平面展布以及生、储、盖组合关系，认为有利的沉积相带主要是三角洲、扇三角洲前缘、湖底扇、近岸水下扇的中扇和外扇以及滨浅湖中发育的滩坝和砂坝。
Three sets of source rocks had been formed juring the steady sinking of the basin . the first source rock , being clay and calcium clay stone in tiemulike formation of permian was formed in deep lake environment ; the second source rock , being clay stone in xiaoquangou group of middle to upper triassic was formed in the offshore and the shallow lake environment ; and the third source rock , being coal beds in badaowan formation of lower jurassic was formed in the lake - swamp environment . the first one is the most potential , since it has the biggest thickness , the highest organic matter abundance , high maturity and the highest hydrogen generating capacity 在盆地稳定沉降时期，相应地形成三套烃源岩，即上二叠统铁木里克组( p _ ( 2t ) )深湖、半深湖相泥岩、泥灰岩；中上三叠统小泉沟群( t _ ( 2 - 3xq ) )滨浅湖相泥岩及下侏罗统八道湾组( j _ ( 1b ) )湖沼相煤系地层。
Furthermore , sixteen sedimentary subfacies are identified . respectively , the sedimentary subfacies are delta plain , delta front , prodelta , braided delta plain , braided delta front , braided prodelta , coastal lake , saucer lake , tidal flat , barrier island , lagoon , carbonate continental shelf , muddy continental shelf , open platform , local platform and evaporate platform 并进一步识别出16种沉积亚相，分别为：三角洲平原、三角洲前缘、前三角洲、辫状河三角洲平原、辫状河三角洲前缘、前辫状河三角洲、滨湖、浅湖、潮坪、障壁岛、泻湖、碳酸盐陆棚、泥质陆棚、开阔台地、局限台地和蒸发台地。
