中国陆内造山带造山过程地球动力学分析     

蔡学林  魏显贵  刘援朝  吴德超  邓明森  石绍清  曹家敏 《矿物岩石》1998,(Z1)

本文论证了我国陆内造山带岩石圈结构、造山过程岩石圈浅层变形构造样式、盆山变形构造时空耦合关系、造山过程与沉积盆地变形动力学模式等。提出中国西部造山带造山过程岩石圈变形总体是：上部以伸展变形为主,中部以挤压变形为主,下部以伸展变形为主。通过中国造山带造山过程与沉积盆地变形作用时空耦合关系对比研究,首次建立起造山过程与沉积盆地形成时空耦合关系的三类四型动力学模式：单向楔入造山推覆成盆、双向楔入造山推覆成盆、剪切造山反转成盆和伸展造山断陷成盆模式。  相似文献   

论楔入造山作用──以龙门山造山带为例   总被引：5，自引：1，他引：5  

蔡学林  魏显贵  刘援朝  曹家敏 《四川地质学报》1996,(2)

本文以龙门山造山带为例，根据对阿尔泰—台湾地学断面地质学、地球物理学和地球化学等的综合研究，重点讨论了龙门山造山带岩石圈楔状构造的几何结构样式，探讨了碰撞后的陆内造山过程、造山模式及其科学意义。  相似文献   

Enregistrement de la dernière remontée du niveau marin dans l'architecture interne d'une vallée incisée : le pertuis Breton (Charente-Maritime)     

Nicolas Weber  Éric Chaumillon  Michel Tesson 《Comptes Rendus Geoscience》2004,336(14):1273-1282

Recent very high-resolution seismic profiles ground-truthed by vibrocores allow us to evidence an atypical incised valley fill in a drowned valley segment, the ‘Pertuis Breton’ (Bay of Biscay, France). The sedimentary valley-fill architecture mainly includes five superimposed progradational wedges composed by marine sands. Sandbodies show a landward migration of their depocentres upward and are topped by almost flat unconformities extended by submarine terraces. This sedimentary infill pattern is similar to backstepping wedges, described on continental shelfs. It suggests that this valley fill records sea-level rise during the last transgression. To cite this article: N. Weber et al., C. R. Geoscience 336 (2004).  相似文献   

Tectonic wedging along the rear of the offshore Taiwan accretionary prism     

Wu-Cheng Chi  Donald L. Reed  Greg Moore  Tuan Nguyen  Char-Shine Liu  Neil Lundberg 《Tectonophysics》2003,374(3-4):199-217

The structural geometry, kinematics and density structure along the rear of the offshore Taiwan accretionary prism were studied using seismic reflection profiling and gravity modeling. Deformation between the offshore prism and forearc basin at the point of incipient collision, and southward into the region of subduction, has been interpreted as a tectonic wedge, similar to those observed along the front of mountain ranges. This tectonic wedge is bounded by an east-dipping roof thrust and a blind, west-dipping floor thrust. An east-dipping sequence of forearc-basin strata in the hanging wall of the roof thrust reaches a thickness in excess of 4 km near the tip of the interpreted tectonic wedge. Section restoration of the roof sequence yields an estimate of 4 km of shortening, which is small compared with that inferred in the collision area to the north, based on the variation in distance between the apex of the prism and the island arc.Previous studies propose that either high-angle normal faulting or backfolding has exhumed the metamorphic rocks along the eastern flank of the Central Range in the collision zone on land. To better constrain the initial crustal configuration, we tested 350 crustal models to fit the free-air gravity anomaly data in the offshore region to study the density structure along the rear of the accretionary prism in the subduction and initial collision zones before the structures become more complex in the collision zone on land. The gravity anomaly, observed in the region of subduction (20.2°N), can be modeled with the arc basement forming a trenchward-dipping backstop that is overlain by materials with densities in the range of sedimentary rocks. Near the point of incipient collision (20.9°N), however, the free-air gravity anomaly over the rear of the prism is approximately 40 mgal higher, compared with the region of subduction, and requires a significant component of high density crustal rocks within the tectonic wedge. These results suggest that the forearc basement may be deformed along the rear of the prism, associated with the onset of collision, but not in the subduction region further to the south.  相似文献   

Contrasting Peridotite Types in the Dabie UHP Belt, Eastern China: the Raobazhai and Bixiling Ultramafic-mafic Complex     

Jianping Zheng  Min Sun  W. L. Griffin  Mei-Fu Zhou  Guochun Zhao 《矿物岩石地球化学通报》2007,26(Z1)

The Dabie UHP metamorphic belt, central China,contains two contrasting types of mafic-ultramafic complex. The Bixiling peridotite in the southern Dabie terrane contains abundant garnet (21.1-32.2 vol% )and thus has high CaO + Al2O3 (9.81-15.9 wt% ).  相似文献   

浅谈三峡工程蓄水对兴山库岸的影响     

田东方  刘德富  王世梅  雷体洪  周明涛  胡志宇 《中国地质灾害与防治学报》2005,16(2):24-27

三峡工程三期、四期蓄水后，库岸稳定性将会发生变化。为确定蓄水后对兴山段库岸稳定性的影响，文章在对兴山段库岸地质勘查的基础上，确定了兴山地区区域和库岸地质、水文条件特征。对各个库岸分段选取典型剖面，采用广义楔形体法对剖面的稳定性进行计算及评价。计算结果显示，库岸虽然在自然状态下基本稳定，但安全储备不高。随着蓄水的进行，其稳定性将进一步降低，造成一定的危害。根据兴山段库岸特点，提出几点简单的库岸防护建议。  相似文献   

强迫型海退及强迫型海退楔体系域--对传统Exxon层序地层学模式的修正   总被引：30，自引：4，他引：26  

梅冥相  杨欣德 《地质科技情报》2000,19(2):17-21

传统Ｅｘｘｏｎ层序地层学模式把层序界面定义在下降拐点,低水位体系域则位于类型Ⅰ层序之底,且低水位体系域（ＬＳＴ）被定义为海平面相对下降期至初始上升阶段的产物;但是,在建立海平面变化曲线时,又假定层序界面位于海平面变化的最低点,从而造成层序地层学概念体系的下连贯性。强迫型海退被定义为与沉积物注入无关,而与相对海平面下降相关的滨线向海方向迁移的海退过程,由此而产生的一系列沉积体则构成强迫型海退楔体系域  相似文献   

PRELIMINARY STUDY ON THE OPHIOLITIC MELANGE IN THE YALU TSANGPU GRAND CANYON AREA   总被引：1，自引：0，他引：1  

Geng Quanru  Pan Guitang  Liu Yuping  Zheng Lailing  Liu Chaoji WT  ”BX 《地学前缘》2000,(Z1)

PRELIMINARY STUDY ON THE OPHIOLITIC MELANGE IN THE YALU TSANGPU GRAND CANYON AREA  相似文献   

河西走廊末次冰期芒硝和砂楔与古气候重建   总被引：10，自引：0，他引：10  

王乃昂  王涛  高顺尉  史正涛  胡刚 《地学前缘》2000,(Z2)

芒硝和砂楔是冷干气候环境的典型标志。河西走廊砂楔主要形成在晚更新世冲洪积砾石层中 ,楔体内充填的风成砂14 C年龄证明其是末次冰期的产物 ,古砂楔所对应的年均气温为- 5 6℃左右。芒硝主要分布在内陆河终端的盐湖中 ,花海芒硝矿粘土夹层中的陆生树枝残条普通14 C和AMS14 C年龄分别为 (116 0 0± 2 80 )aB .P .和 (11181± 54)aB .P .,证明芒硝层为末次盛冰期 (LGM )和新仙女木期 (YD)异常冷干气候的产物。计算表明 ,该区LGM年均气温较现在低 11～ 15℃ ,YD年均气温比现代低约 6～ 8℃。这一降温幅度与中国北方根据孢粉、砂楔、冰芯等所推测的气温下降值大体一致 ,亦与最近有关北半球高、中纬度冰期降温幅度的研究相符合  相似文献   

九龙江口-厦门港河口盐度锋面的特征   总被引：7，自引：1，他引：6  

王伟强  张远辉  黄自强 《台湾海峡》2000,19(1):82-88

本文着重研究九龙江口－厦门港冬季小潮实测的各潮时盐度锋面,发现其具有锋面宽度窄、盐度梯度很大,平面上等盐线大致成西北－东南走向、横断面上则较多呈向南向下倾斜的特征,其锋面盐度在１５～２７之间,锋面宽度约在２．６～４．３ｋｍ之间,盐度梯度在２．１～２．６ｋｍ＾－１之间;但盐度锋面区的位置、宽度和盐度梯度随潮位、水深的变化而变化。落急时各盐度锋面都在象鼻嘴与屿仔尾连线以西,并随水深的增加不断向西推移,  相似文献