杨率, 金振奎, 韩建辉. 南海北缘白云凹陷新生代岩浆活动特征与期次[J]. 海洋地质与第四纪地质, 2017, 37(6): 34-46. DOI: 10.16562/j.cnki.0256-1492.2017.06.004
引用本文: 杨率, 金振奎, 韩建辉. 南海北缘白云凹陷新生代岩浆活动特征与期次[J]. 海洋地质与第四纪地质, 2017, 37(6): 34-46. DOI: 10.16562/j.cnki.0256-1492.2017.06.004
YANG Shuai, JIN Zhenkui, HAN Jianhui. CENOZOIC MAGMATIC ACTIVITIES AND STAGES IN THE BAIYUN SAG, NORTHERN MARGIN OF SOUTH CHINA SEA[J]. Marine Geology & Quaternary Geology, 2017, 37(6): 34-46. DOI: 10.16562/j.cnki.0256-1492.2017.06.004
Citation: YANG Shuai, JIN Zhenkui, HAN Jianhui. CENOZOIC MAGMATIC ACTIVITIES AND STAGES IN THE BAIYUN SAG, NORTHERN MARGIN OF SOUTH CHINA SEA[J]. Marine Geology & Quaternary Geology, 2017, 37(6): 34-46. DOI: 10.16562/j.cnki.0256-1492.2017.06.004

南海北缘白云凹陷新生代岩浆活动特征与期次

CENOZOIC MAGMATIC ACTIVITIES AND STAGES IN THE BAIYUN SAG, NORTHERN MARGIN OF SOUTH CHINA SEA

  • 摘要: 白云凹陷隶属于南海北缘珠江口盆地珠二坳陷,进入新生代以后白云凹陷及其邻区发育了剧烈的、多期次的岩浆活动,表现为强烈的火山喷发与岩浆侵入作用。从白云凹陷地质资料、井资料、地震资料出发,井震结合总结了不同类型岩浆岩体地震响应特征, 并识别出了白云凹陷新生代发育的岩浆岩体,绘制了岩浆岩体平面分布图。白云凹陷新生代岩浆岩体主要分布于白云凹陷周围的隆起或凸起部位,且以白云凹陷南侧为主要分布区,白云凹陷内部岩浆岩体发育较少,在凹陷内部呈零星分布。利用岩浆活动期次划分方法(接触关系法、上覆沉积地层厚度法、两侧地层对比法),将白云凹陷新生代岩浆活动分为4期:32~23.8、23.8~10.5、10.5~5.5、5.5 Ma至今,绘制了各时期岩浆岩发育平面图,第1期对应构造演化阶段中的断拗转换期,后3期对应构造演化阶段中的拗陷期,并且随着区域构造演化的进行岩浆活动具有减弱的特征。

     

    Abstract: The Baiyun Sag is a second-order depression of the Pearl River Mouth Basin located on the northern margin of the South China Sea. Since Cenozoic, it has suffered strong magmatic activities characterized by both intensive eruption and intrusion. By integration of geological and seismic data, this paper summarized the seismic features of different types of magmatic bodies and some Cenozoic magmatic bodies were distinguished from the others. Spatial distribution pattern of the magmatic bodies was mapped. It is found that the Cenozoic magmatic bodies are mainly distributed on uplifts or higher parts around the Baiyun sag, especially on the south side. Magmatic bodies are few within the sag. Using the traditional classification of magmatic stages based upon contact relationship, thickness of sediment cover and stratigraphic correlation, the Cenozoic magmatic activities in the Baiyun sag might be grouped into four periods: 32~23.8 Ma, 23.8~10.5 Ma, 10.5~5.5 Ma, and 5.5 Ma up to present. Spatial distribution maps are compiled for each period. The first period corresponds to the transforming stage from faulting to depression. The next three, however, are all within the stage of depression. The magmatic activities weakened with time.

     

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