【24h】

#

机译:丽江—贵阳重力剖面揭示峨眉山大火成岩省地壳的密度结构%#

获取原文
获取原文并翻译 | 示例
       

摘要

The Emeishan large igneous province (hereafter named by its acronym ELIP) is the first accepted large igneous region in China. The current study tries to reconstruct the density structure of the crust in this region. For this purpose, we conducted the gravity survey along an 800-km-long profile, which stretched laterally along the latitude 27°N from Lijiang (Yunnan province) to Guiyang (Guizhou province). The fieldwork included 338 gravity measurements distributed from the inner zone to the outer zone of the mantle plume head. After a series of gravity reductions, we calculated the Bouguer gravity anomaly and then constructed the density model for ELIP by iterative forward modeling from an initial density model tightly constrained by wide-angle seismic reflection data. The topography of the Moho, here physically interpreted as a density discontinuity of ~0.4 g·cm–3, gradually rises from the inner zone (~50 km deep) to the outer zone (~40 km), describes a thicker crust in the inner zone than in any other segment of the profile and largely reproduces the shape of the Bouguer gravity anomaly curve. Both the Bouguer gravity and the density structure show significant differences with respect to the inner zone and the other two zones of ELIP according to the commonly accepted partition of the Emeishan area. A thicker and denser middle-lower crust seems to be the main feature of the western section of the profile, which is likely related to its mafic magmatic composition due to magmatic underplating of the Permian mantle plume.%#
机译:峨眉山大火成岩省(以下简称为ELIP)是中国第一个公认的大火成岩地区。当前的研究试图重建该地区地壳的密度结构。为此,我们沿800公里长的剖面进行了重力测量,该剖面从云南丽江(贵州省)到贵阳(贵阳省)沿纬度27°N横向延伸。现场工作包括338次重力测量,从地幔柱头部的内部区域分布到外部区域。经过一系列的重力折减后,我们计算了布格重力异常,然后从由广角地震反射数据严格约束的初始密度模型中,通过迭代正向建模,为ELIP建立了密度模型。莫霍面的地形,在物理上被解释为密度不连续性〜0.4 g·cm–3,从内部区域(深约50 km)到外部区域(约40 km)逐渐上升,描述了该地区较厚的地壳。内部区域比轮廓的任何其他部分都大,并且在很大程度上重现了布格重力异常曲线的形状。根据峨眉山地区普遍接受的划分,布格重力和密度结构相对于ELIP的内部区域和其他两个区域都显示出显着差异。较厚和较密的中下地壳似乎是剖面西部的主要特征,这可能是由于二叠纪地幔柱的岩浆基底作用而引起的镁铁质岩浆成分。%#

著录项

  • 来源
    《地球与行星物理(英文)》 |2018年第001期|74-81|共8页
  • 作者

    #;

  • 作者单位

    #;

  • 收录信息
  • 原文格式 PDF
  • 正文语种 chi
  • 中图分类
  • 关键词

    #;

    机译:#;
  • 入库时间 2022-08-19 03:36:47
获取原文

客服邮箱:kefu@zhangqiaokeyan.com

京公网安备:11010802029741号 ICP备案号:京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有
  • 客服微信

  • 服务号