山东省东北部车镇凹陷古近系沙河街组滨浅湖沉积中的遗迹群落

济阳坳陷车镇凹陷古近系沙河街组滨浅湖沉积中产有十分丰富的动物遗迹化石,共鉴定出遗迹属 10个,未定属 1个,其中遗迹种 7个,未定种 4个。遗迹化石包括Beaconitesantarcticus, Beaconitescapronus, Planolitesmontanus, Macaronichnussegregatis, Taenidiumbarretti, Cochlichnusanguineus, Gordiasp., Skolithossp., Ophiomorphanodosa, Sagittichnussp.和Favreinasp.。这一遗迹化石群落主要是无脊椎动物的进食迹、觅食迹、居住迹和停息迹,其中大部分呈全浮痕保存,少数呈上浮痕保存,并形成于经常干旱和周期性泛滥的滨浅湖沉积环境中。该群落可识别出两个遗迹化石组合,即 1)Beaconites Taenidium组合,它主要产自干旱气候条件下的滨浅湖沉积环境;2)Sko lithos Ophiomorpha组合,它代表了丰水期水体能量相对较高的滨湖沉积环境。

ICHNOCOENOSIS OF SHORE-SHALLOW LACUSTRINE SHAHEJIE FORMATION (PALEOGENE) IN CHEZHEN SAG, JIYANG DEPRESSION OF BOHAIWAN BASIN, SHANDONG

This ichnocoenosis from the Paleogene Shahejie Formation consists of at least 10 ichnogenera 11 ichnospecies, namely, Beaconites antarcticus, Beaconites capronus, Planolites montanus, Macaronichnus segregatis, Taenidium barretti, Cochlichnus anguineus, Gordia sp., Skolithos sp., Ophiomorpha nodosa, Sagittichnus sp. and Favreina sp. Besides, a type of unknown arthropod crawling trace is also described in this paper. These trace fossils represent Fodinichnia, Pascichnia, Domichnia and Cubichnia of invertebrates such as Vermes, Mollusca, Arthropoda (mainly insects) and others. Most of them were formed in a regularly desiccated shore-shallow lacustrine environment and preserved in full relief and epirelief.Two ichnofossil assemblages are recognized: (1) Beaconites-Taenidium Assemblage, reflecting a shore-shallow lake sedimentary environment under periodically arid climate; and (2) Skolithos-Ophiomorpha Assemblage, representing a relatively high energy shore lake under humid climate.