东辛地区沙三段遗迹化石特征与沉积环境分析

Ichnofossil characteristics and depositional environment of Es3 reservoir in Dongxin Area

陈秀艳¹ 姜在兴² 师晶³ 徐杰²

中国石油勘探开发研究院，北京 100083 中国地质大学（北京）能源学院，北京 100083 香港天地能源服务有限公司北京代表处，北京 100015

Research Institute of Petroleum Exploration and Development, PetroChina, Beijing 100083, China School of Energy Resources, China University of Geosciences, Beijing 100083, China Beijing Representative Office of Tiandi Energy Service Limited Company of Hong Kong, Beijing 100015, China

通过岩心观察及沉积分析，东辛地区沙三段发育大量的生物潜穴、逃逸构造、扰动构造及生物实体化石和印模，可进一步识别为居住迹（Domichnia）、进食迹（Fodinichnia）、牧食迹（Pascichnia）３大类。根据组合特征，可划分为Cochlichnus　anguineus，Planolites montanus和Skolithos?鄄Planolites　３种遗迹组合。沙三下亚段发育Cochlichnus anguineus遗迹组合及完整鱼化石，代表相对安静的低能沉积环境；沙三中亚段发育Planolites montanus遗迹组合，见逃逸构造和扰动构造，表明水体存在动荡时期，但大部分时间处于相对安静环境；沙三上亚段发育Skolithos?鄄Planolites遗迹组合，见扰动构造、螺类化石及印模，代表处于高能沉积环境。整体表明，该区沙三段沉积时期，从下至上水体逐渐变浅，水动力条件逐渐增强。

According to core observation and sedimentation analysis, Es3 reservoir of Dongxin area is enriched with trace fossils, which contains dwelling burrow, escape structure, bioturbation structure, biological entity fossil and impression. The ichnocoenosis can be recognized as Domichnia, Fodinichnia and Pascichnia. Based on the distribution characteristics, ichnocoenoses can be subdivided into Cochlichnus anguineus, Planolites montanus and Skolithos-Planolites. Cochlichnus anguineus and perfect fish fossils are developed in Lower Es3, which represents the depositional environment is quiet. Planolites montanus, escape structure and bioturbation structure are developed in Middle Es3, which indicates the water body is sometimes turbulent，but it is in relatively quiet environment in most of the time. Skolithos-Planolites, bioturbation structure, snail fossil and impression are developed in Upper Es3, which indicates the reservoir is in the depositional environment with high energy. All the study results show that hydrodynamic conditions were enhanced gradually and the water depth was getting shallow upward in the depositional period of Es3 member of Dongxin Ａrea.

10.6056/dkyqt201204014