山东省唐王寨上寒武统崮山组沉积环境及竹叶状灰岩的多成因分析(英文)

Multiple origins for flat-pebble limestones and sedimentary environments of the Upper Cambrian Gushan Formation at Tangwangzhai in Shandong Province

华北地台上寒武统崮山组出现了大量的竹叶状灰岩。通过对山东唐王寨剖面崮山组的系统研究,识别出页岩、疙瘩状泥晶灰岩、泥质条带泥晶灰岩、薄层状泥晶灰岩、生物扰动泥晶灰岩、颗粒质(生物碎屑)泥岩—泥质颗粒岩、含交错层理鲕粒灰岩及竹叶状灰岩8种岩石类型,这些岩石类型组成了页岩盆地、深潮下带及浅潮下带岩石组合。竹叶状灰岩中砾屑和基质的特征及其沉积序列,表明砾屑和基质的来源多样并且在不同的沉积环境中其成因具有多样性。据此总结出崮山组竹叶状灰岩具有4种可能的成因类型:1)竹叶状灰岩中砾屑和基质可能均为原地形成或者仅有短距离的搬运过程;2)竹叶状灰岩中砾屑和基质可能均为近岸形成并经历了长距离的搬运过程,或者竹叶状灰岩的沉积环境经历了海平面的突然升高;3)竹叶状灰岩中基质可能来源于近岸未固结的鲕粒和生物碎屑及原地的灰泥,与原地破碎生成的砾屑和灰泥等混合沉积;4)竹叶状灰岩中砾屑可能来源于远岸的固结的泥晶灰岩,并经搬运作用与原地未固结的灰泥及骨架颗粒等基质混合沉积。

The Upper Cambrian Gushan Formation in North China Platform is characterized by a- bundant deposition of flat-pebble limestones （flat-pebble conglomerates）. The flat-pebble limestone re- fers to the so-called edgewise-limestone. Based on the systematic investigation of the sedimentology of the Gushan Formation at the Tangwangzhai Section, Shandong Province, 8 rock types, namely calcareous shale, nodular micritic limestone, muddy banded micritic limestone, thin-bedded micritic limestone, bioturbated micritic limestone, skeletal wackestone-packstone, oolitic grainstone, and flat-pebble limestone, have been recognized in this formation, and have been grouped into 3 rock associations, which were deposited in the shaly basin, deep subtidal zone and shallow subtidal zone. The characteristics of pebbles and matrix and sedimentary successions indicate different provenances for the pebbles and ma- trix, and suggest that flat-pebble limestones in the Gushan Formation were originated from multiple sedi- mentary environments. Flat-pebble limestones in the Gushan Formation are grouped into 4 types according to their origins. 1 ） Both pebbles and matrix were probably formed in situ or transported only for a short distance; 2） Both pebbles and matrix were eroded and transported for a long distance from nearshore regions or experienced a sea-level rising process; 3 ） Matrix might be transported from nearshore regions, and mixed with pebbles and lime mud formed in situ; 4） Pebbles might be eroded and trans- ported from micritic limestone on far offshore regions, and mixed together with matrix in situ, such as lime mud and skeletal grains.