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1.
深地震测深是探测壳幔岩石圈精细速度结构、探讨岩石圈变形和演化过程的一种有效方法,在青藏高原隆升、克拉通裂解等大陆动力学研究中已发挥了重要的作用。然而,地震测深方法与深部动力学研究的结合尚处于现象描述为主的状态。因此,本文对前人利用深地震测深资料进行深部动力学研究的相关方法进行了回顾与总结:宽角反射/折射地震震相特征具有明显的动力学响应,是进行动力学研究的基础;通过速度结构对比可以确定不同地壳速度结构模型所对应的构造单元及其演化过程,地壳厚度和泊松比等参数可以用于地壳变形模式的讨论,壳内高速和低速异常体反映了不同动力学过程对地壳的改造;人工地震S波资料与Pn波速度可以用于壳幔各向异性的研究,为动力学演化过程研究提供独立的观测证据;运用现代构造解析方法可以构建不同的地壳结构—动力型式,进而通过壳幔结构的解构恢复岩石圈演化过程;此外,地震测深资料可以约束地壳成分结构,为动力学数值模拟提供岩石流变参数等资料。本文对于充分挖掘深地震测深资料在动力学研究中的应用价值至关重要,对于加强地震测深同其他学科的交叉研究也具有重要意义。 相似文献
2.
《地质论评》2021,(1)
深地震测深是探测壳幔岩石圈精细速度结构、探讨岩石圈变形和演化过程的一种有效方法,在青藏高原隆升、克拉通裂解等大陆动力学研究中已发挥了重要的作用。然而,地震测深方法与深部动力学研究的结合尚处于现象描述为主的状态。因此,本文对前人利用深地震测深资料进行深部动力学研究的相关方法进行了回顾与总结:宽角反射/折射地震震相特征具有明显的动力学响应,是进行动力学研究的基础;通过速度结构对比可以确定不同地壳速度结构模型所对应的构造单元及其演化过程,地壳厚度和泊松比等参数可以用于地壳变形模式的讨论,壳内高速和低速异常体反映了不同动力学过程对地壳的改造;人工地震S波资料与Pn波速度可以用于壳幔各向异性的研究,为动力学演化过程研究提供独立的观测证据;运用现代构造解析方法可以构建不同的地壳结构—动力型式,进而通过壳幔结构的解构恢复岩石圈演化过程;此外,地震测深资料可以约束地壳成分结构,为动力学数值模拟提供岩石流变参数等资料。本文对于充分挖掘深地震测深资料在动力学研究中的应用价值至关重要,对于加强地震测深同其他学科的交叉研究也具有重要意义。 相似文献
3.
华北裂陷盆地不同块体地壳结构及演化研究 总被引：22，自引：0，他引：22
通过对华北裂陷盆地内不同块体的深地震测深资料处理 ,得到与构造演化过程相关的、不同性质块体的地壳结构特征。盆地隆起区块体地壳一般呈均匀成层 ,速度随深度逐层增加 ,保留了古大陆地壳块体的稳定结构特征 ;盆地坳陷区块体地壳松散巨厚的表层沉积、通常低速占主导的壳内构造、强反射的下地壳和高低速相间的薄互层壳 幔过渡带 ,反映了上地幔物质上隆、侵入、地壳增温、张裂等塑、脆性变形改造的新生地壳构造。讨论了这两类截然不同块体地壳构造的地球动力学演化及形成。裂陷区内中强地震的孕发和深源矿产、油气生贮存等都与这两类块体地壳结构、构造密切相关。 相似文献
4.
喜马拉雅造山带的地壳上地幔结构——近震反射观测结果 总被引：1，自引：0，他引：1
2002-2005年完成了穿越喜马拉雅山的宽频地震探测,采用了沿剖面紧密排列的台站布置并获得了近震中的反射波资料,这对地壳和岩石圈内部速度界面的研究有重要意义.地震数据及研究结果表明,青藏高原的地震主要发生于上地壳范围内,高原莫霍面反射波的纵波PmP与横波SmS波至清晰可辨且有很强的能量,在跨越雅鲁藏布江时PmP和SmS均发生了错动,表现为北深南浅.在改则至鲁谷沿线所记录到的发生在拉萨地块的Fw21事件的地震数据中,拉萨地块内部的莫霍面反射波,尤其是SmS波至非常清晰连续,地壳纵波平均速度为Vp=6.3km/s,表明拉萨地块内部Moho面平坦、连续,不存在突起与错位.在此Moho面之前出现壳内较强反射界面,埋深45kin可能正是下地壳的顶界面.P208事件中PmP和SmS均清晰可见,然而在距震中450km及其以远地段存在两个清晰的震相PLt及SLt,并且其能量很强,可能是位于160km深处的岩石圈底界面的反映.根据对近震资料的分析研究,本文建立了该地区的地壳上地幔的结构模型. 相似文献
5.
长白山及邻区地壳、上地幔顶部三维速度结构 总被引：2，自引：0，他引：2
根据沿长白山布设的宽频带流动地震台站及吉林省地震台网所记录的近震P波走时数据,利用层析成像方法对长白山及邻区（39°N-45°N、122°E-130°E）深至40 km的地壳和上地幔顶部三维速度结构进行了研究。结果表明：地震的发生和分布多集中于断裂等复杂地质构造。利用较高分辨率的地壳、上地幔顶部三维速度结构证实了长白山火山区岩浆囊存在,并推测岩浆囊的位置位于火山口的西南方向,深度为10~40 km。壳内岩浆囊分布对进一步解释、认识火山灾害提供了重要的深部信息。 相似文献
6.
大陆浅源地震震源空间分布可以看作是一种地球物理特征,大量震源的空间位置数据可用来刻划大陆地壳结构。通过研究南北地震带南段震源的空间分布特征,发现研究区震源深度分布在横向上的疏密变化与地质构造特征相对应。剖面震源分布等密度图显示,中、下地壳不同深度广泛分布着多震层。多震层的分布与地壳低速、低阻层具有相关性,多震层一般位于低速、低阻层的上方。中地壳层次的低速、低阻层很可能是壳内滑脱层,是韧性下地壳与脆性上地壳发生拆离解耦的构造层次;下地壳低速、低阻层是部分熔融、含流体的韧性流变层;壳内多震层的构造属性应是上地壳硬的脆性层,容易发生突然破裂,产生地震。低速、低阻层是大陆板块内部上地壳脆性层构造过程的主控因素,包括对大陆内部浅源地震的控制;因此,在低速、低阻层之上往往形成多震层,越是活动性强的低速、低阻层,其上多震层震源密度越高。南北地震带南段不同层圈和块体之间的差异运动控制了其地壳层次的构造活动,包括大量地震的发生,其中,下地壳流层与上地壳脆性层的差异运动在中地壳层次发生剪切拆离是最重要的因素。 相似文献
7.
在松Ⅰ～松Ⅵ6条深反射地震剖面上依据震相特征并结合地质演化过程分析识别石炭—二叠系,分析其层位反射特征及同相轴特征,建立松辽盆地北部地区石炭—二叠系地震震相特征识别标志。主要震相特征为中—强反射能量,局部存在高值,整体同相轴连续—较连续,由南到北、由西向东规律变化。利用已有的钻遇石炭—二叠系的探井资料和地震波传播速度,得到研究区时间-深度转换关系。由研究区石炭—二叠系相位追踪对比后的反射时间分布,计算石炭—二叠纪地层顶界面与底界面在深反射地震时间剖面上的走时之差,通过时深转换得出研究区基底石炭—二叠纪地层厚度和分布。全区地层分布不很均匀,主要在中央隆起带以东地区及西部断陷区出现2个厚度高值区;地层整体由浅到深大致可分为上、中、下3层,且地震震相特征互不相同。松辽盆地北部石炭—二叠系分布对东北地区主力油层之下的深层油气勘探提供了有价值的依据。 相似文献
8.
新疆地学断面 (泉水沟 独山子 )深地震测深剖面的分段成果已经先期分别发表 ,根据已经发表的资料 ,本文着重全线震相的对比 ,并讨论地壳构造与地质演化的关系。该剖面全长约 12 0 0km ,南起西昆仑山 ,穿过塔里木盆地 ,跨越天山 ,止于准噶尔盆地南缘。该剖面共设 12个炮点 ,共用炸药 2 0t,投入地震仪 12 0台 ,共获有效三分量记录 973个。在折合时间记录截面图上识别出 6个震相 (Pg,P2 ,P3,P4,Pm,Pn) ,经走时反演和射线追踪拟合获得速度结构模型。最终的模型显示塔里木盆地主体的地壳厚度为 3 8～ 4 6km ,而且塔里木南缘的Moho界面南倾 ,与结晶基底南倾的角度大体一致。从塔中隆起至西昆仑山前 ,Moho面深度从 4 0± 2km加深到 5 7km ,但继续向南深入到西昆仑北坡之下 ,Moho产状变平 ,深度减小到 5 4km。以西昆仑北坡基底抬升、下地壳增厚和山前凹陷内存在巨厚沉积的观测事实为依据 ,推断塔里木盆地南缘地壳向西昆仑山下俯冲 ,但俯冲的距离和深度可能有限。天山地区观测到了清楚的Pn 震相 ,速度为 8.15km/s。整个天山地区Moho平均深度为 5 2km ,地壳结构复杂 ,其中地壳为 3～ 7km厚 ,速度值 5 .6km/s的低速层。中天山之下的Moho略显隆起 ,中、北天山交界处Moho明显错断。地壳内部各层厚度横向变化较大 ,具 相似文献
9.
地球深部壳-幔边界的层束精细结构与物理属性研究 总被引：6，自引：1，他引：6
滕吉文 《吉林大学学报(地球科学版)》2006,36(1):1-23
地球深部壳幔边界的介质结构和属性在地球内部圈层结构,特别是岩石圈结构与深层动力过程的研究中占有重要地位。这不仅由于它是地壳与上地幔的分界,而且它与深部物质的分异、调整及其深、浅物质的运移和耦合密切相关。研究结果表明:①通过地震宽角反射和近垂直反射波场效应可分辨其精细结构;②壳幔边界具有高低速相间的薄层、层束状多态结构;③来自壳幔边界复杂结构的地震反射波和宽角反射波具有明显的和各异的波场特征,并具有明显的动力学响应;④壳幔边界是一个主体由榴辉岩组构的化学界面;⑤给出了壳幔边界的广义模式。 相似文献
10.
通过最近完成的格尔木—额济纳旗地学断面的研究,揭示了青藏高原北部(柴达木—祁连山)至中蒙边境北山地区的地壳结构构造、物质组成及其构造演化,提供了大量有关该地区深部构造的信息。确定了在断面内莫霍界面最深处位于南祁连哈拉湖以南的居洪吐地带,深度值为74km,并与祁连山主峰不相对应。柴达木盆地地壳厚度平均55km,盆地中央莫霍界面略有隆起。北山地区莫霍界面较为平缓,平均地壳厚度为45 km。深地震测深资料发现,沿整个断面地壳内20km深度附近存在着一个连续的低速层,厚度一般为5～10km,速度值在5.80～6.05 km/s间变化,一般与上覆层位有0.3～0.5kn/的速度差。大地电磁测深发现的壳内高导层沿断面全线展布,但埋深及厚度均变化较大。壳内高导层的电阻率明显降低,约5～10Ω·m。从横向上来看,不同地体的地壳结构具有明显的不同。 通过对断面走廊域地质构造及发展历史的研究,划分出6个不同的构造-地层地体、由北而南分别为:北山北部地体,北山南部地体,北祁连地体,中—南祁连地体,柴达木—北昆仑地体和南昆仑地体,并提出了它们在古生代及其以前时期,分属哈萨克斯坦—准噶尔、塔里木、华北—柴达木和华南 -扬子等不同板块。到早二叠世末,随着古亚洲洋和阿尔金洋盆的闭 相似文献
11.
Hiroshi Sato Naoshi Hirata Takaya Iwasaki Makoto Matsubara Takeshi Ikawa 《Tectonophysics》2002,355(1-4)
Knowledge of the crustal structure, especially the geometry of seismogenic faults, is key to understanding active tectonic processes and assessing the size and frequency of future earthquakes. To reveal the relationship between crustal structure and earthquake activity in northern Honshu Island, common midpoint (CMP) deep reflection profiling and earthquake observations by densely deployed seismic stations were carried out across the active reverse faults that bound the Ou Backbone range. The 40-km-long CMP profiles portray a relatively simple fault geometry within the seismogenic layer. The reverse faults merge at a midcrustal detachment just below the base of the seismogenic layer, producing a pop-up structure that forms the Ou Backbone range. The top of the reflective middle to lower crust (4.5 s in travel time (TWT)) nearly coincides with the bottom of seismogenic layer. The P-wave velocity structure and surface geology suggest that the bounding faults are Miocene normal faults that have been reactivated as reverse faults. 相似文献
12.
Crustal structure of mainland China from deep seismic sounding data 总被引：18，自引：0，他引：18
Since 1958, about ninety seismic refraction/wide angle reflection profiles, with a cumulative length of more than sixty thousand kilometers, have been completed in mainland China. We summarize the results in the form of (1) a new contour map of crustal thickness, (2) fourteen representative crustal seismic velocity–depth columns for various tectonic units, and, (3) a Pn velocity map. We found a north–south-trending belt with a strong lateral gradient in crustal thickness in central China. This belt divides China into an eastern region, with a crustal thickness of 30–45 km, and a western region, with a thickness of 45–75 km. The crust in these two regions has experienced different evolutionary processes, and currently lies within distinct tectonic stress fields. Our compilation finds that there is a high-velocity (7.1–7.4 km/s) layer in the lower crust of the stable Tarim basin and Ordos plateau. However, in young orogenic belts, including parts of eastern China, the Tianshan and the Tibetan plateau, this layer is often absent. One exception is southern Tibet, where the presence of a high-velocity layer is related to the northward injection of the cold Indian plate. This high-velocity layer is absent in northern Tibet. In orogenic belts, there usually is a low-velocity layer (LVL) in the crust, but in stable regions this layer seldom exists. The Pn velocities in eastern China generally range from 7.9 to 8.1 km/s and tend to be isotropic. Pn velocities in western China are more variable, ranging from 7.7 to 8.2 km/s, and may display azimuthal anisotropy. 相似文献
13.
B.R. Goleby R.S. Blewett T. Fomin S. Fishwick A.M. Reading P.A. Henson B.L.N. Kennett D.C. Champion L. Jones B.J. Drummond M. Nicoll 《Tectonophysics》2006,420(1-2):75
The collection of a range of different seismic data types has greatly improved our understanding of the crustal architecture of Australia's Archaean Yilgarn Craton over the last few years. These seismic data include broadband seismic studies, seismic receiver functions, wide-angle recordings and mine-scale to deep seismic reflection transects. Each data set provides information on the three-dimensional (3D) tectonic model of the Yilgarn Craton from the craton scale through to the mine scale. This paper demonstrates that the integration and rationalisation of these different seismic data sets into a multi-scale 3D geological/seismic model, that can be visualised at once in a single software package, and incorporating all available data sets, significantly enhances this understanding. This enhanced understanding occurred because the integrated 3D model allowed easy and accurate comparison of one result against another, and facilitated the integrated questioning and interrogation across scales and seismic method. As a result, there are feedback questions regarding understanding of the individual seismic data sets themselves, as well as the Yilgarn Craton as a whole.The methodology used, including all the data sets in the model range, had to allow for the wide range of data sets, frequencies and seismic modes. At the craton scale, P-wave, S-wave and surface wave variations constrained the 3D lithospheric velocity model, revealing noticeable large-scale velocity variations within and across the craton. An interesting feature of the data, easily identified in 3D, is the presence of a fast S-wave velocity anomaly (> 4.8 km s− 1) within the upper mantle. This velocity anomaly dips east and has a series of step-down offsets that coincide approximately with province and terrane boundaries of the Yilgarn Craton.One-dimensional receiver function profiles show variations in their crustal velocity across the craton. These crustal velocity variations are consistent with the larger-scale geological subdivision of the craton, and provide characteristic profiles for provinces and terranes. The receiver function results and the deep seismic reflection data both agree on the depth to the Moho, and both indicate an increase in Moho depth to the east. The 2D seismic refraction results in the south-west of the craton provide crustal thickness information, an indication of middle and lower crustal compositions, and information regarding the broad-scale architectural framework.At the province- and terrane-scale, the deep seismic reflection data and the mine-scale seismic data provide geometric constraints on crustal architecture, in particular the orientation of the region's fault systems as well as variations in the thickness of the granite–greenstone succession. Integration of the results from wide-angle seismic refraction data coincident with the deep seismic reflection data provided additional constraints on likely upper crustal lithologies.The integrated 3D seismic model implies the dominant geodynamic process involved the development of an orogenic belt that developed with a series of contractional (folding and thrusting) events, separated by equally important extensional events. The seismic reflection data in particular suggests that extensional movement on many shear zones was more common than previously thought.The seismic reflection data suggest that the dominant mineral systems involved deeply sourced fluid flowing up crustal-penetrating shear zones. These deeply sourced fluids were further focussed into sites located above fault-breached domal regions in the upper crust. 相似文献
14.
Crustal thicknesses previously estimated by [J. Geophys. Res. 107 (2002) 2] in SE Brazil varied from 47 km in the middle of the Paraná basin to approximately 35 km in the Ribeira fold belt. We study the crustal structure of the Ribeira belt in more detail by identifying the Ps Moho converted phase and its multiple reflection PpPms, as well as using waveform modeling of receiver functions. We use phase-weighted slant stacking to identify the Ps and PpPms arrival times, which provides the vP/vS beneath each station. In inverting the receiver functions, we use average crustal velocities and initial models obtained from a deep seismic refraction line, as well as data from a timed quarry blast. The crustal thickness ranges 34–42 km with a thinning trend toward the coast. Crustal thickness correlates with elevation, indicating approximate regional Airy isostasy. Along the Serra do Mar coastal range, the average crustal Poisson ratio is about 0.25. The southern part of the Mantiqueira range has a higher Poisson ratio of 0.28. Stations near the São Francisco craton have a lower Poisson ratio of 0.23. 相似文献
15.
Anomalous crustal and upper mantle structure of northern Juan de Fuca plate is revealed from wide-angle seismic and gravity modelling. A 2-D velocity model is produced for refraction line II of the 1980 Vancouver Island Seismic Project (VISP80). The refraction data were recorded on three ocean bottom seismometers (OBSs) deployed at the ends and middle of a 110 km line oriented parallel to the North American continental margin. The velocity model is constructed via ray tracing and conforms to first-arrival amplitude observations and travel time picks of direct, converted and reflected phases. Between sub-sediment depths of 3 to 11 km, depths normally associated with the lower crust and upper oceanic mantle, the final model shows that compressional-wave velocities decrease significantly from southeast to northwest along the profile. At sub-sediment depths of 11 km at the northwestern end of the profile, P-wave velocities are as low as 7.2 km/s. A complementary 2-D gravity model using the geometry of the velocity model and velocity–density relationships characteristic of oceanic crust is produced. The high densities required to match the gravity field indicate the presence of peridotites containing 25–30% serpentine by volume, rather than excess gabbroic crust, within the deep low velocity zone. Anomalous travel time delays and unusual reflection characteristics observed from proximal seismic refraction and reflection experiments suggest a broader zone of partially serpentinized peridotites coincident with the trace of a pseudofault. We propose that partial serpentinization of the upper mantle is a consequence of slow spreading at the tip of a propagating rift. 相似文献
16.
江陵凹陷北部高速玄武岩下二维广角地震初探 总被引：2，自引：0，他引：2
江汉油田江陵凹陷北部高速玄武岩发育,利用常规地震资料很难得到高速玄武岩下的地震反射。分析研究表明,广角地震有利于玄武岩下的地震成像。通过综合正演和实际地震数据完成了广角地震资料的处理,获得了江陵凹陷北部高速玄武岩下的反射地震信息。在开展广角地震波场的识别和利用研究过程中,从正演模型出发,探讨了在不同地质条件下高速层对地震波场的影响,并针对靶区资料讨论了如何识别广角地震信息。在上述基础上,通过对实际地震资料做精细的分析和处理,最终完成了高速玄武岩下地震资料的成像。 相似文献
17.
F. Hauser V. Raileanu W. Fielitz A. Bala C. Prodehl G. Polonic A. Schulze 《Tectonophysics》2001,340(3-4):233-256
The VRANCEA99 seismic refraction experiment is part of an international and multidisciplinary project to study the intermediate depth earthquakes of the Eastern Carpathians in Romania. As part of the seismic experiment, a 300-km-long refraction profile was recorded between the cities of Bacau and Bucharest, traversing the Vrancea epicentral region in NNE–SSW direction.
The results deduced using forward and inverse ray trace modelling indicate a multi-layered crust. The sedimentary succession comprises two to four seismic layers of variable thickness and with velocities ranging from 2.0 to 5.8 km/s. The seismic basement coincides with a velocity step up to 5.9 km/s. Velocities in the upper crystalline crust are 5.9–6.2 km/s. An intra-crustal discontinuity at 18–31 km divides the crust into an upper and a lower layer. Velocities within the lower crust are 6.7–7.0 km/s. Strong wide-angle PmP reflections indicate the existence of a first-order Moho at a depth of 30 km near the southern end of the line and 41 km near the centre. Constraints on upper mantle seismic velocities (7.9 km/s) are provided by Pn arrival times from two shot points only. Within the upper mantle a low velocity zone is interpreted. Travel times of a PLP reflection define the bottom of this low velocity layer at a depth of 55 km. The velocity beneath this interface must be at least 8.5 km/s.
Geologic interpretation of the seismic data suggests that the Neogene tectonic convergence of the Eastern Carpathians resulted in thin-skinned shortening of the sedimentary cover and in thick-skinned shortening in the crystalline crust. On the autochthonous cover of the Moesian platform several blocks can be recognised which are characterised by different lithological compositions. This could indicate a pre-structuring of the platform at Mesozoic and/or Palaeozoic times with a probable active involvement of the Intramoesian and the Capidava–Ovidiu faults. Especially the Intramoesian fault is clearly recognisable on the refraction line. No clear indications of the important Trotus fault in the north of the profile could be found. In the central part of the seismic line a thinned lower crust and the low velocity zone in the uppermost mantle point to the possibility of crustal delamination and partial melting in the upper mantle. 相似文献
18.
The Borborema Province of northeastern Brazil is a major Proterozoic crustal province that, until now, has never been explored using deep crustal seismic methods. Here are reported the first results obtained from a high-quality seismic refraction/wide-angle reflection profile that has defined the internal seismic velocity structure and thickness of the crust in this region. Almost 400 recording stations were deployed in the Deep Seismic Refraction (DSR) experiment through an NW–SE ca. 900 km linear array and 19 shots were exploded at every 50 km along the line. Data from the 10 southeastern most shots of the seismic profile were processed in this work. The main features and geological structures crossed by the studied portion of the profile belong to the so-called Central Sub-province of the Borborema tectonic province. The crustal model obtained is compatible with a typical structure of extended crust. The model was essentially divided into three layers: upper crust, lower crust, and a half-space represented by the shallower portion of the mantle. The Moho is an irregular interface with depth ranging between 31.7 and 34.5 km, and beneath the Central Sub-province it varies from 31.5 to 33 km depth, where its limits are related to major crustal discontinuities. The distribution of velocities within the crust is heterogeneous, varying vertically from 5.7 to 6.3 km/s in the upper crust and from 6.45 to 6.9 km/s in the lower crust. From the average crustal velocity distribution it is evident that the Central Sub-province has seismic characteristics different from neighboring domains. The crust is relatively thin and crustal thickness variations in the profile are subtle due to stretching that occurred in the Cretaceous, during the fragmentation of Pangaea, opening of the South Atlantic Ocean and separation of South America from Africa. 相似文献
19.
大陆岩石圈解耦及块体运动讨论——以青藏高原—川滇地区为例 总被引：6，自引：0，他引：6
块体构造理论的发展不断地深化着人们对现今大陆岩石圈运动 ,尤其是大陆强震的孕育和发生规律的认识。块体底部边界的构造性质是块体运动的核心问题之一 ,同时也是块体构造理论研究中的薄弱环节。确定块体底部边界的岩石物理性质是利用地球物理方法探测和识别块体底部边界的前提。文中依据现代实验岩石学、实验岩石物理学、地球物理学、地质学等的研究成果 ,对块体底部边界之成因属性和岩石物理性质进行了分析。将大陆块体划分为两种基本类型———地壳型块体和岩石圈型块体。地壳型块体是由大陆上部地壳所构成的“薄板” ,壳内软弱带的顶面为其底部边界和潜在的解耦带。岩石圈型块体在岩石圈尺度上是力学耦合的 ,以上地幔软流圈的顶面为其底部边界。壳内软弱带具有垂直方向低速和各向异性的基本特征 ,联合多种地震测深方法有望确定块体的底界。在现今构造活动区内 ,地壳型块体的潜在解耦带可能由壳内部分熔融带承担。青藏高原南部—川滇地区 2 0 35km的深度上广泛存在低速带。地热、岩石学、实验岩石学和模拟均显示该地区的低速带具有部分熔融的成因属性。块体沿着该壳内低速层与下伏地壳发生某种程度解耦。 相似文献