石油与天然气地质 ›› 1999, Vol. 20 ›› Issue (4): 273-278.doi: 10.11743/ogg19990401

• 前沿探索 •    下一篇

沉积盆地地球动力学系统的研究─以辽西-辽北-松辽盆地南部为例

王东坡1, 许敏1, 薛林福1, 刘立1, 王德勤2   

  1. 1. 长春科技大学 吉林长春 130026;
    2. 王氏有限公司 美国加利福尼亚州 83704
  • 收稿日期:1999-07-26 出版日期:1999-12-25 发布日期:2012-01-16
  • 基金项目:

    中国石油天然气总公司科研项目;"95"东部深层前期重点科研项目;辽河石油勘探局科研项目

STUDIES ON GEODYNAMIC SYSTEMS OF SEDIMENTARY BASINS:TAKING WEST LIAONING, NORTH LIAONING AND SOUTH SONLIAO BASIN FOR EXAMPLE

Wang Dongpo1, Xu Min1, Xue Linfu1, Liu li1, Wang Deqin2   

  1. 1. Changchun of Science and Technique, Changchun, Jilin;
    2. Wang, Ins., CA, U. S. A
  • Received:1999-07-26 Online:1999-12-25 Published:2012-01-16

PDF (PC)

556

被引次数

29

摘要：

盆地形成和演化过程与地球深部动力系统的演化过程有密切关系。地球深部动力系统主要包括岩石圈、软流圈以及莫霍面。岩石圈的厚度、有效弹性厚度以及流变性决定了它对构造活动、热活动以及变形的响应,控制了拆离带的深度,影响了盆地的热结构,进而影响到盆地的结构类型。软流圈不仅对岩石圈底部产生熔蚀作用,使岩石圈变薄,而且还直接影响到岩石圈的热学性质。莫霍面是一个动态的界面,从大的方面看,反映了不同大地构造单元的地壳结构;从小的方面看,指示了盆地的形成模式。在中国东北地区,从早、中侏罗世到早白垩世早期形成众多的断陷盆地,早白垩世晚期于松辽地区形成大型坳陷盆地。这些盆地沿松辽盆地-辽北-辽西一线呈有规律的排列,其含油气性由西北向东南由断陷含气坳陷含油,过渡为含气断陷不含油坳陷,到最后断陷中不含油气。油气的这种分布规律表面上看与盆地类型有关,实际上是受盆地深部地球动力系统的控制。主要体现在:(1)松辽盆地岩石圈厚度约50～60km,平均比辽西地区薄25km;岩石圈厚度越大拆离带的深度就越大;折离带深度越大,岩石圈的强度越大。由此可见,松辽盆地的岩石圈强度明显低于辽西地区,因此更易发生挠曲变形而形成坳陷盆地。(2)由于盆地的基底存在较大的差异,松辽盆地与辽西地区的地热结构存在较大差异,松辽盆地地慢热流(Qr)为58.1 mW/m2,且Qr/Qs=77%,辽西地区地慢热流仅为36.8 mW/m2, Qr/Qs=59%;壳慢边界的温度也是松辽盆地(744.4℃)比辽西地区(644℃)高。这一地热结构是造成松辽盆地与辽西地区热沉降幅度存在差异的根本原因。

关键词: 盆地, 地球动力学, 系统, 岩石圈, 拆离带, 软流圈, 莫霍面

Abstract:

The formation and evolution of a basin is related closely to evolution of the dynamic system in the deep of the earth. The dynamic system mainly consists of the lithosphere, the asthenosphere and the Moho. The thickness of the lithosphere, effective elastic thickness and flowability decide tectonic and thermal artivities and theion, control the depth of detachment, thect thermal texture and architectural types of the basin. The asthenosphere does not only corrode the bottom of the lithosphere, but also affect direcily its thermal property. The Moho is a mobile inteiface. On the whole, it reflects the crustal architecture of different tectonic units; microscopically, it indicats basin-forming model. In North China,a lot of fault-depressed basins formed from Early-Middle Jurassic to early Early Cretaceous and a large depressed basin formed in the late Early Cretaceous in Shongliao Region. These basins are distrituted regularly along Shedao BasinNorth Liaoning-West Liaoning, and hydrocarbons-bearing property changes from gas-bearing fault-depression to depression without oil, until at last fault-depression with no oil and gas at all. This seems to be related to the types of basins, but acturally it is controlled by dymamic systems in the deep of the earth. The main facts are as follows:(1)The lithosphere thickness is about 50～60 km in Shongliao Basin, 25 km thinner than that in West Liaoning. This indicates that the thicker the lithosphere is, the deeper the detachment belts will be, and the bigger the intensity of the lithosphere will be. The intensity of the lithosphere in Shongliso Basin is lower than that in West liaoning. (2)Since there are considerable differences in the basements of the basins, geothermal structure in Shongliao Basin is different from that in West Liaoning. The mantle heat flow Qr=58.1 mW/m2 in Shongliao Basin, Qr/Qs=77%,and the mantle heat flow is only 36.8 mWm2,Qr/Qs=59% in West liaoning. The temperabe of crust-mantle boundary in Shogliao Basin(744.4℃)is higher than that in West Liaoning(644C).The geothermal structure is the basic role that caused thermal subsident differences between Shongliao Basin and West Liaoning region.

Key words: basin, geodynamics, system, lithosphere, detachment zone, asthenosphere, Moho

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