Discussion on origin for marls of the Member 3 of Shahejie Formationof Paleogene in Shulu Sag of Central Hebei Depression
Liang Hongbin Kuang Hongwei Liu Junqi Guo Yongjun Su Jing
1 Research Institute of Petroleum Exploration & Development,PetroChina Huabei Oilfield Company, Renqiu062552, Hebei
2 Key Laboratory of Exploration Technologies for Oil and Gas Resources, Ministry of Education,
School of Geophysics and Oil Resources, Yangtze University, Jingzhou434023, Hubei
A special type of rock suite was discovered in the lower part of the Member 3 of Shahejie Formation of Paleogene in the Shulu Sag of Central Hebei Depression, Hebei Province, which is neither typical carbonate rocks nor classic clastic rocks. Based on detailed observations of cores and thin sections combined with comprehensive analyses of testing data, it is known as the hunji rock. Hunji rock (in broad sense) as well as the concept and system about mixing deposits were introduced into the classification of sediment type and lithofacies and thus provide proofs for scientific definition of marl. According to their origin, hunji rock can be divided into three types: textural mixing, interbedded mixing and interlayered mixing deposits. Each type can be subdivided into several kinds: textural mixing deposits include rocks mainly composed of terrigenous components and rocks that mostly consist of intrabasinal composition. Interbedded mixing deposits is the most important types of rocks. Laminated microcrystalline limestones are mainly composed of limymudstone, marl and micrite which make up light and dark ribbons with organicrich materials sometimes. The arranges of lamina are various and can be subdivided into 4 types in terms of the different contents of composition in situ and allogene composition. Interlayered mixing deposit consists of thicklybedded conglomerate (carbonate breccia) intercalated with the former two types of hunji rock. Tectonics, climate and provenance are the principal factors for controlling the formation of Hunji Rock.
About author: Liang Hongbin, born in 1963, graduated and obtained his doctoral degree from Chinese Academy of Sciences in 2005. Now he is a senior engineer at Research Institute of Petroleum Exploration and Development, PetroChina Huabei Oilfield of Company, and is engaged in sedimentology and oil exploration technology and administration.
Cite this article:
. Discussion on origin for marls of the Member 3 of Shahejie Formationof Paleogene in Shulu Sag of Central Hebei Depression[J]. JOURNAL OF PALAEOGEOGRAPHY, 2007, 9(2): 167-174.
. Discussion on origin for marls of the Member 3 of Shahejie Formationof Paleogene in Shulu Sag of Central Hebei Depression[J]. JOPC, 2007, 9(2): 167-174.
