石油与天然气地质 ›› 2024, Vol. 45 ›› Issue (1): 142-156.doi: 10.11743/ogg20240110

• 油气地质 • 上一篇    

鄂尔多斯盆地古峰庄地区疑似侵入岩体的发现及其地质意义

杨丽华1,2(), 刘池洋1,2(), 黄雷1,2, 周义军3, 刘永涛3, 秦阳1,2   

  1. 1.大陆动力学国家重点实验室, 陕西 西安 710069
    2.西北大学 含油气盆地研究所, 陕西 西安 710069
    3.东方地球物理公司研究院 长庆分院, 陕西 西安 710021
  • 收稿日期:2023-10-24 修回日期:2023-12-11 出版日期:2024-02-01 发布日期:2024-02-29
  • 通讯作者: 刘池洋 E-mail:201921119@stumail.nwu.edu.cn;lcy@nwu.edu.cn
  • 第一作者简介:杨丽华（1996—），女，博士，油气地质勘探与盆地动力学。E-mail：201921119@stumail.nwu.edu.cn。
  • 基金项目:
    国家自然科学基金项目(41330315);西北大学大陆动力学国家重点实验室科学技术部专项(201210142)

Discovery of suspected intrusive rock bodies in Gufengzhuang area， Ordos Basin and its geological significance

LiHua YANG1,2(), ChiYang LIU1,2(), Lei HUANG1,2, Yijun ZHOU3, Yongtao LIU3, Yang QIN1,2   

  1. 1.State Key Laboratory of Continental Dynamics，Northwest University，Xi’an，Shaanxi 710069，China
    2.Institute of Oil and Gas，Northwest University，Xi’an，Shaanxi 710069，China
    3.Changqing Branch of Geophysical Research Institute，BGP Inc. ，Xi’an，Shaanxi 710021，China
  • Received:2023-10-24 Revised:2023-12-11 Online:2024-02-01 Published:2024-02-29
  • Contact: ChiYang LIU E-mail:201921119@stumail.nwu.edu.cn;lcy@nwu.edu.cn

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摘要：

鄂尔多斯盆地内部岩浆岩体的发现对于构造-热事件重建、古地温场恢复及油气地质作用解析有重要意义。基于高精度三维地震资料的处理与解释，首次在盆地内部古峰庄地区发现疑似浅层侵入岩体，刻画了其空间展布并探讨了油气地质意义。研究显示，古峰庄地区存在6个疑似侵入岩体，在平面上多呈环状或云朵状，剖面上愈临近岩体核部，地层杂乱反射和丘状构造特征愈明显。据岩体分布形式和地震反射特征，可将其分为“岩浆深分散浅集中上涌型”疑似侵入岩体和“岩浆浅集中上涌型”疑似侵入岩体。前者由深及浅均有杂乱反射现象，与围岩反射特征明显有别，产状近直立，伴生断裂发育。后者仅在1 000 ms等时切片以上的浅部层系呈杂乱丘状反射，其下地层呈正常的层状反射、几乎不见地层扰动现象。分析认为先存断裂的存在及其数量、规模、垂向叠置程度、核部与端部断距以及地层压力，是造成岩浆差异式上涌的主因。结合盆内其他岩浆岩体发育特征和形成时代，认为古峰庄疑似侵入岩体形成于早白垩世晚期，与古生界-中生界油气规模成烃期和成藏期一致，此阶段的热液活动对该区油气生成、保存和成藏具有重大意义。

关键词: 构造-热事件, 侵入岩体, 古峰庄地区, 鄂尔多斯盆地

Abstract:

Magmatic rocks within the Ordos Basin are crucial for reconstructing tectono-thermal events， paleogeothermal fields， and petroleum geological processes. Based on the processing and interpretation of high-resolution 3D seismic data， we identify suspected intrusive rock bodies in shallow strata in the Gufengzhuang area， Ordos Basin， marking the first discovery of such geological structures in this area. Furthermore， we characterize their spatial distributions and explore their geological significance. The results reveal six rock bodies interpreted as intrusive rocks in the Gufengzhuang area， most of which are ring- or cloud-shaped in a planar view. As shown on seismic sections， strata closer to the cores exhibit more pronounced chaotic reflections and more significant characteristics of mounded structure. Based on their distribution patterns and seismic reflection characteristics， these intrusive rock bodies as interpreted can be classified into two types： the deep scattered and shallow concentrated type with magma upwelling and the shallow concentrated type with magma upwelling. The geological structures of the former type exhibit chaotic seismic reflections as caused by magma intrusion from deep to shallow， significantly distinct from the seismic reflections of their surrounding rocks. Furthermore， they are characterized by nearly vertical occurrences and associated faults. In contrast， only the shallow strata of the latter type display chaotic mounded seismic reflections （corresponding time slices at 1 000 ms and less）， while the deeper strata show normal layered reflections with almost no disturbance. Analyses suggest that the differential magma upwelling is primarily caused by the presence of pre-existing faults and their quantity， scale， degree of vertical superimposition， and throws at cores and ends， as well as formation pressure. By combining the developmental characteristics and formation eras of other magmatic rocks within the Ordos Basin， this study proposes that the intrusive rock bodies as interpreted in the Gufengzhuang area were formed during the late Early Cretaceous， which is consistent with the scale hydrocarbon generation and accumulation period of Paleozoic-Mesozoic oil and gas， and the hydrothermal activity in this stage is of great importance to the generation， preservation and accumulation of hydrocarbons in this area.

Key words: tectono-thermal event, intrusive rock body, Gufengzhuang area, Ordos Basin

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