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1.
3-D rheological structure is mainly the spatial distribution of lithospheric strength or viscos-ity, its strength and viscosity are indispensable parameters in quantitative study of the lithosphere deformation. Plate tectonics theory initially divided the… 相似文献
2.
In this work we have modeled the thermal structure of the lithosphere of the Spanish Central System and the Tajo Basin, and their implications for lithospheric strength. For this, we have used refined heat-producing elements (HPE) values to obtain new estimates of heat production rates in the Spanish Central System and Tajo Basin areas, which have been used joined to the relation between topography and thermal structure of the lithosphere to calculate the best-fit surface heat flows in the study area. Moreover, we have implemented a temperature-dependent thermal conductivity (appropriate for olivine) for the lithospheric mantle to improve the calculations of temperature profiles in the mantle. The geotherms so obtained, together with the implementation of a new rheological law for the upper lithospheric mantle, have been used to calculate refined estimations of the strength and effective elastic thickness of the lithosphere. We have obtained surface heat flow values of 84 mW m−2 and ∼82 mW m−2 for the Spanish Central System and the Tajo Basin, respectively. The thermal state of the lithosphere affects mantle temperatures, and hence may be playing an important role in the uplift and maintenance of the Spanish Central System. 相似文献
3.
在大地热流密度分布的基础上，研究了塔里木盆地中库尔勒－若羌和阿克苏－叶城两条剖面岩石层热结构特征．由岩石层Ｐ波速度分布转换成生热率剖面，用二维数值模型获得了岩石层热结构和热状态特征．结果表明，塔里木盆地壳幔边界温度的高低与其埋深密切相关．居里等温面深度大，地幔热流密度较低．岩石层厚度变化与其新生代期间挠曲过程密切相关．在岩石层温度分布基础上，确定了深部脆－韧性过渡带深度和岩石层屈服强度，表明塔里木盆地岩石层相对较冷，且具有刚性的地球动力学特征． 相似文献
4.
LIU Shaowen WANG Liangshu GONG Yuling LI Cheng LI Hua & HAN Yongbing . Department of Urban Resources Nanjing University Nanjing China . Department of Earth Sciences Nanjing University Nanjing China 《中国科学D辑(英文版)》2005,48(10)
Thermal regime of the lithosphere is the scenario of the lithospheric thermal evolution, and the thermo-mechanical state of lithosphere definitively controls its deformation style and mechanism. Better understanding of the lithospheric deep thermal-rheo- logical structure of sedimentary basin will shed light on the formation and evolution dynamic process of the basin. Surface tectonics is the response of the deep structure, and is controlled by the lithospheric ther-mal-rheological properties.… 相似文献
5.
岩石圈热结构是盆地现今地温场研究的重要延伸和扩展,是了解大陆岩石圈构造变形及演化等大陆动力学问题的重要窗口,更是地热田热源机理研究的核心问题.本次工作,在系统分析渭河盆地现今地温场和水动力系统基础上,编制了渭河盆地大地热流分布等值线图;通过实测生热率等热物性参数,利用一维稳态热传导方程计算了研究区岩石圈热结构,并分析了渭河盆地岩石圈热结构特征和地热田热源机理.结果表明,渭河盆地现今大地热流值分布范围为62.5~80.2mW·m-2,平均为70.8±4.8mW·m-2,西部明显高于东部,西安坳陷最高,咸礼凸起次之;渭河断裂并不是控热断裂,其沟通作用引起的水热循环一定程度上影响了浅部热量再分配,对渭河盆地地温场并没有起到明显的控制作用.西安坳陷—咸礼凸起地壳热流介于32.2~37.5mW·m-2之间,平均为34.6mW·m-2;地幔热流分布范围为33.8~38.9mW·m-2,平均为36.0mW·m-2;地壳热流和地幔热流的总体变化趋势一致,西安坳陷高于咸礼凸起,分析认为西安坳陷沉积层厚度大于后者,且沉积层放射性生热率更大,是造成西安坳陷地壳热流高于咸礼凸起的原因,而西安坳陷相比咸礼凸起更高的地幔热流,表明西安坳陷深部活动性强于咸礼凸起.西安坳陷和咸礼凸起地壳/地幔热流比值相近,介于0.93~1.01之间,平均为0.96,"热"岩石圈厚度约为95~101km.渭河盆地岩石圈热结构特征与鄂尔多斯盆地在很大程度上具有相似性,暗示着二者具备相似的深部稳定性,这与渤海湾盆地为代表的中国东部中—新生代主动裂谷盆地岩石圈热结构特征截然不同,表明渭河盆地为被动伸展裂陷.从鄂尔多斯盆地、渭河盆地、山西裂谷到华北盆地,"热"岩石圈厚度的有序变化表明太平洋板块俯冲引起的地幔对流对华北地块深部动力学行为的影响主要发生在太行山以东,而太行山以西的鄂尔多斯盆地和渭河盆地则影响甚微,这种空间差异影响从侧面暗示着华北克拉通破坏过程的有序性.综合分析渭河盆地地质—地球物理资料认为,岩石圈表层伸展破裂、深部重力均衡调整进而引起软流圈被动上涌,其产生的相对高地幔热流的热传导和深大断裂沟通的水体热对流相互叠加作用,共同构成了渭河盆地中—低温地热田的热源机理. 相似文献
6.
沉积盆地岩石圈热结构特征是岩石圈构造-热演化过程的综合反映和盆地热史恢复的约束条件,对盆地动力学研究和油气资源评价具有重要意义.由于海洋勘探难度大、勘探程度低,相对于大陆地区,边缘海盆地比较缺乏岩石圈热结构方面的研究.本文在收集整理珠江口盆地及邻区大地热流数据的基础上,补充收录了自2003年以来发表的新数据,绘制了研究区最新版的大地热流等值线图;基于中美合作双船地震剖面揭示的深部地壳结构计算了研究区的壳-幔热流、深部温度以及"热"岩石圈厚度.研究表明,珠江口盆地地壳热流介于18.7~28.6 mW·m-2,地幔热流介于36.9~91.4 mW·m-2,壳幔热流比值0.23~0.75;由陆架、陆坡至中央海盆,在地壳热流逐渐减小的情况下地表热流逐渐递增,说明地表热流分布主要受深部热作用控制;盆地"热"岩石圈厚度介于34.0~87.2 km,平均65.5 km,反映出显著拉张减薄的特征. 相似文献
7.
南海地区岩石圈资料稀少,阻碍了其形成演化过程的研究.为此,本次研究结合大地热流、空间重力异常、高程、大地水准面和地震数据,在南海西南次海盆反演了两条2.5维岩石圈剖面.本次计算基于三种假设：岩石圈地幔的密度取决于岩石温度;研究区岩石圈处于热稳定状态;研究区处于重力均衡状态.在剖面A-E中,岩石圈底界面从珠江口盆地的105 km迅速抬升到西沙海槽处的50 km,在西沙海槽、西沙-中沙群岛和西南次海盆变化不大,为50~60 km.在剖面F-I中,岩石圈底界面从西沙群岛-中建地块处的88 km向海盆逐渐抬升,在西南次海盆处为46~50 km,到郑和隆起再逐渐变深至64 km.我们比较了西南次海盆岩石圈的冷却模型和热稳定模型,根据冷却模型由水深和热流数据所推断的西南次海盆年龄比实际年龄差很多,说明冷却模型不适用于西南次海盆.通过对比剖面A-E和剖面F-I,说明了剖面A-E经历了更长时间的拉伸,证明南海西南次海盆在形成演化过程中是从北东向南西逐步打开的渐进式扩张.最后,我们综合分析西南次海盆及其大陆边缘的岩石圈结构、减薄陆壳区范围、碳酸盐台地的分布、下地壳韧性流动、流变结构和沉积层特征等多方面资料,认为西南次海盆在形成演化过程中岩石圈地幔首先破裂而地壳后破裂,属于type Ⅱ型非火山型大陆边缘. 相似文献
8.
青藏高原岩石圈的流变学结构和形变机制是地学界长期争论的重大科学问题.2001年发生在东昆仑断裂带的MW7.8可可西里地震造成青藏高原北部地区岩石圈构造应力场的很大改变,引起下地壳与上地幔的快速弛豫形变,从而为研究这一问题提供了难得的机会.本研究采用该区域的GPS震后观测,反演这一地区岩石圈的流变学参数并探讨其形变机制.反演所采用的数据来自45个GPS观测点,其中包括一个中国地壳运动观测网络的基准站,数据最长时间跨度达6.4年.大地震震后形变场主要来源于地壳、上地幔的黏弹性松弛与断层面上的震后余滑,因此本研究同时反演介质的黏滞系数和断层的震后余滑.考虑到东昆仑断层南侧的巴颜喀拉-羌塘地区与北侧的柴达木盆地地区具有明显不同的地壳结构,断层南北两侧采用不同的Burgers体流变学结构,其下地壳-上地幔的短期和长期黏滞系数采用网格搜索法获得;断层震后余滑反演则同时施加近似正比于库仑应力的约束.最终结果显示：东昆仑断层北侧柴达木盆地地区下地壳-上地幔短期和长期黏滞系数分别为5×1018 Pa·s和1.5×1020 Pa·s;东昆仑断层南侧巴颜喀拉-羌塘地区下地壳-上地幔短期和长期黏滞系数分别为1.5×1018 Pa·s和1.5×1019 Pa·s.这一结果表明：巴颜喀拉-羌塘地区下地壳-上地幔黏滞系数显著低于柴达木盆地,意味着巴颜喀拉-羌塘地区下地壳可能存在部分熔融,其地壳形变模式更趋近于连续形变,而柴达木盆地形变模式更趋近于块体运动.研究区下地壳长期黏滞系数比下地壳流模型所主张的黏滞系数高2~3个数量级,表明下地壳流在本地区可能不存在. 相似文献
9.
Guoming Gao Lan Shi Guofa Kang Yingyan Wu Chunhua Bai Limin Wen Jing Hou 《Studia Geophysica et Geodaetica》2018,62(3):408-426
In this paper, the CHAMP satellite data from the last decade are used to map the lithospheric magnetic field in continental China at altitudes of 300 and 400 km using the spline function model technique. The results show that our model has higher amplitude than the spherical harmonic magnetic field model MF7. The resulting lithospheric anomaly distribution of continental China agrees with the geotectonic structure and crustal thermal structure. The magnetic anomaly distribution clearly indicates extrusion of the Tibetan Plateau towards the northeast and northwest directions. Northward movement is impeded by the relative rigid Tarim Basin featured with positive magnetic anomalies. The positive magnetic anomalies in Tarim basin extend to the northern Tibetan Plateau, suggesting that the southern part of Tarim Basin underthrusted the northern Tibetan Plateau. 相似文献
10.
An explosive seismic sounding profile across the transition zone between west Kunlun Mts. and Tarim Basin 总被引：1，自引：0，他引：1
LI Qiusheng GAO Rui LU Deyuan Li Jingwei Fan Jingyi Zhang Zhiying LIU Wen LI Yingkang YAN Quanren LI Dexing 《中国科学D辑(英文版)》2001,44(7):666-672
The explosive seismic sounding profile across the transition zone from the west Kunlun Mts. to the Tarim Basin revealed the
complex deep structure formed by continent-continent collision on the northern margin of the Tibetan Plateau. The profile
shows that the attitude of the Moho is in agreement with that of the crystalline basement in the Tarim Basin and the whole
crust dips as a thick slate southwards with an angle from 5° to 7°. Meanwhile, the Moho depth increases from 40 km to 57 km
within a distance of 150 km in the southern Tarim region, depicting the subduction of the crust of this region towards the
west Kunlun Mts. The crust of the northern slope of the west Kunlun Mts. shows an evident compressed and shortened feature,
that is, the basement is uplifted, the interface dips northwards and the Moho rises abruptly to become flat, so that the lower
crust is as thick as 20 km. 相似文献
11.
12.
TAN Hongbing MA Haizhou XIAO Yingkai WEI Haizhen ZHANG Xiying & MA Wandong . Institute of Salt Lakes Chinese Academy of Sciences Xining China . Graduate School of the Chinese Academy of Sciences Beijing China 《中国科学D辑(英文版)》2005,48(11):1913-1920
The Tarim Basin, located in Xinjiang (Fig. 1), is the largest deposit basin with an area of about 560000 km2 in China. From late Triassic period to early Miocene, two huge subbasins developed, named the Kuqa sub-basin at the foot of the Tianshan Mountains in the north and the Shaqa subbasin at the foot of the Kunlun Mountains in the south of the Tarim Basin. During the late Cretaceous to early Tertiary period, the Paleo-me- diterranean seawater repetitively invaded into the Shaqa subbas… 相似文献
13.
S. Thomas Crough 《Earth and Planetary Science Letters》1979,44(2):224-230
Recent advances in the measurement and interpretation of geoid height anomalies provide a new way to estimate the thickness of the oceanic lithosphere as a function of crustal age. GEOS-III satellite altimetry measurements show abrupt changes in sea level across fracture zones which separate areas of lithosphere with different ages. These changes have the correct location, amplitude, and wavelength to be caused by the combined gravitational attraction of the relief across the fracture zone and the isostatic support of this relief. Eight profiles of geoid height and bathymetry across the Mendocino fracture zone are inverted to determine the depth of the isostatic compensation, assuming that the compensation occurs in a single layer. These depths are then interpreted with a thermal boundary layer model of lithospheric growth. To explain satisfactorily the geoid measurements, the thermal diffusivity of the upper mantle must be 3.3 × 10?3 cm2 s?1 and the thickness of the lithosphere, defined as the depth at which the geotherm reaches 95% of its maximum value, must be9.1km m.y.?1/2 × t1/2, where t is lithospheric age. 相似文献
14.
沿塔里木盆地中部的库车—塔中—塔南测线,首次进行了地震转换波测深。探测结果表明,本区岩石圈具有明显的层状－块体结构,地壳厚度４０～５０ｋｍ,隆起区约为４０ｋｍ,凹陷区约为５０ｋｍ。上地壳的厚度在盆地中部明显减薄,中地壳波速相对偏高（ＶＰ＝６．４～６．５ｋｍ／ｓ）,下地壳上部普遍存在低速薄层,结晶地壳的速度高于周围青藏高原和天山地区的波速,波速结构表明地壳具有陆壳性质,地壳内存在具有逆冲性质的深部断裂。综合解释认为,自新生代以来,在印度－欧亚板块边界的强大挤压力作用下,岩石圈内包括结晶基底面和莫霍面在内的各深部界面（岩层）的准同步挠曲变形和地壳刚性块体沿深部逆冲断裂的调整运动,是塔里木盆地岩石圈中主要的深部动力学过程 相似文献
15.
本文利用三维有限差分方法,基于EIGEN6C4布格重力异常和SIO V15.1地形数据,计算了青藏高原东南缘岩石圈有效弹性厚度.结果表明:青藏高原东南缘岩石圈有效弹性厚度为0~100 km,四川盆地和喜马拉雅东构造结岩石圈有效弹性厚度最大,达50~100 km;巴颜喀拉块体东部、川滇菱形块体大部、滇西等地区岩石圈强度弱,有效弹性厚度一般小于15 km;羌塘块体东部的玉树—德格附近地区岩石圈有效弹性厚度大于40 km;滇南地区岩石圈有效弹性厚度为10~30 km,大于云南北部地区.研究区域有效弹性厚度分布特征与岩石圈结构关系密切.四川盆地、喜马拉雅东构造结地区内部结构稳定,因而岩石圈强度大.川滇菱形块体等岩石圈有效弹性厚度小的地区与壳内低速、低阻/高导层分布有很好的对应关系,推测壳内岩石的部分熔融软化可能是造成高原东南缘岩石圈强度较弱的重要原因.羌塘块体东部的局部高力学强度岩石圈则可能是高原形成过程中的残留克拉通.根据本文计算的岩石圈有效弹性厚度特征,结合地震学、大地电磁等研究成果,认为青藏高原物质向东南缘挤出后受四川盆地等阻挡,造成下地壳软弱物质在理塘—稻城—丽江一带堆积,少部分物质可能穿过鲜水河断裂带的康定—道孚地区向北运动,但大部分物质向南运动,在受到滇南块体阻挡后一支流向西南的腾冲方向,另一支流向东南的攀枝花—东川方向. 相似文献
16.
上地幔温度是控制地幔流变性和动力学过程的关键参数之一.本文利用高分辨率S波地震层析成像速度结果,基于岩石温度与地震波速度的关系,研究了华北地区上地幔50~300 km深度范围内的温度分布和"热"岩石圈厚度.为了验证结果的可靠性,本文用计算的上地幔60 km深度处的温度作为底面约束,得到了相应的地表热流.计算地表热流与观测地表热流之间符合程度较好,相对误差大部分都在地表热流观测误差范围之内.通过对上地幔的温度分布进行分析,我们研究发现:(1)在上地幔浅部,温度与地表构造之间有很好的对应关系.在小于170 km的深度上,温度呈现东高西低的分布态势.温度较高的区域集中在东部的河淮盆地、渤海湾盆地、华北平原和中部陆块的交界处、西部鄂尔多斯高原北缘的银川―河套地堑以及阴山地区,同时,这些地区的岩石圈厚度也相应较薄,大约为80~100 km;(2)西部的鄂尔多斯高原是整个华北地区岩石圈地幔温度最低的地区,比东部地区低200~400 ℃,岩石圈厚度相应最厚,平均岩石圈厚度达到140~150 km,最厚处超过160 km.(3)在170 km以下的软流圈地幔部分,温度分布发生反转,西部温度高于东部,表明东、西部陆块在地质历史时期经历了不同的深部地幔动力学过程. 相似文献
17.
根据大地电磁测深结果,东秦岭河南叶县-湖北南漳地区的岩石层由4个电性单元组成,其中华北地块南缘为相对高温的低阻区;秦岭北部为低温的高阻异常区;南秦岭为高温的低阻区,岩石层平均厚度仅80km,南秦岭的南部推覆到扬子地块之上达40-50km;扬子地块为相对低温的中等电阻率区,岩石层厚度150-200km．利用秦岭地区地壳上地幔岩石样品高温高压条件下电阻率的测定结果推断了各单元岩石层内电性层可能的岩石组成类型,并建立了剖面通过地区岩石层的地电模型． 相似文献
18.
基于二维稳态热传导方程,利用有限元数值模拟方法,选取东西向横穿鄂尔多斯盆地地质与地球物理解释大剖面进行了深部温度场数值模拟研究,得到了华北克拉通西部的鄂尔多斯盆地下伏岩石圈热结构特征.地幔热流变化范围:21.2~24.5mW·m-2,体现为东高西低特征.壳幔热流比(Qc/Qm)介于1.51~1.84之间,为"热壳冷幔".与华北东部地幔热流对比表明,西部的鄂尔多斯盆地相对处于稳定的深部动力学环境.在岩石圈热结构研究基础上,对克拉通地震岩石圈与热岩石圈厚度差异进行了对比,研究表明:鄂尔多斯盆地西部地震岩石圈与热岩石圈厚度差异约达140km,而东部的汾渭地堑,渤海湾盆地二者差异逐渐减小.华北克拉通自西向东,地震岩石圈厚度与热岩石圈厚度差异不断减小,意味着华北克拉通岩石圈下部的软流圈地幔黏性系数自西向东逐渐降低,本文从地热学角度可能印证了太平洋俯冲脱水作用对华北克拉通的影响. 相似文献
19.
The traveling time of the reflection waves of each shot point from the crust-mantle transitional zone has been obtained by
data processing using wavelet transform to the waves reflected from the crust-mantle transitional zone. The crust-mantle transitional
zone of the Xayar-Burjing geoscience transect can be divided into three sections: the northern margin of the Tarim Basin,
the Tianshan orogenic belt and Junggar Basin. The crust-mantle transitional zone is composed mainly of first-order discontinuity
in the Tarim Basin and the Junggar Basin, but in the Tianshan orogenic belt, it is composed of 7–8 thin layers which are 2-3
km in thickness and high and low alternatively in velocity, with a total thickness of about 20km. The discovery of the crust-mantle
transitional zone of the Tianshan orogenic belt and Junggar Basin and their differences in tectonic features provide evidence
for the creation of the geodynamic model “lithospheric subduction with intrusion layers in crust” for the Tianshan orogenic
belt. 相似文献