一次成功的应力预测地震

在冰岛成功地“应力预测”了１次５级地震,做法是根据Ｓ波分裂的时间延迟变化来估计地震的时间和强度,即估计在受应力作用的体积（也是地震释放应变的体积）内微裂隙在应力作用下达到破裂临界点的和强度。当地的研究提供了大致的震中位置。本文叙述了应力预测依据的准则。     

SHRIMP U-Pb Dating of Zircons of a Dark Eclogite and aGarnet-bearing Gneissic Granitic Rock from Bixiling, EasternDabie Area, Anhui Province: Isotope Chronological Evidenceof Neoproterozoic UHP Metamorphism

The paper reports SHRIMP U-Pb zircon data of a dark eclogite and a post-eclogite garnet-bearing gneissic granitic rock from the Bixiling area, Yuexi County, Anhui Province, in the eastern Dabie Mountains. The eclogite, which is metamorphosed basic tuff, contains very scarce zircons in omphacite or garnet, but more zircons in quartz. They usually exhibit a double-layered texture, as shown clearly in cathodoluminescence images. Their inner main parts give a 206Pb/238U age of 757±7 Ma, representing the approximate age of the high-pressure (HP)- ultrahigh-pressure (UHP) metamorphic event during which the eclogite was formed. The outer peripheral parts of the zircons, which have been modified by late-stage fluids, give an age of 223±3 Ma. The granitic rock contains more zircons of anatectic origin found mostly in feldspar and quartz and usually also showing a similar composite texture. The inner main parts of the anatectic zircons with oscillatory zoning give a 206Pb/238U age of 727±15 Ma for the approxim     

CROSS-SECTIONS OF THE WESTERN HIMALAYAN FOOTHILLS:PROBLEMS IN RESTORATION AND IMPLICATIONS FOR CRUSTAL SHORTENING

CROSS-SECTIONS OF THE WESTERN HIMALAYAN FOOTHILLS:PROBLEMS IN RESTORATION AND IMPLICATIONS FOR CRUSTAL SHORTENING1　PowersPM ,LillieRJ ,YeatsRS .StructureandshorteningoftheKangraandDehraDunreentrants ,Sub Himalaya ,India[J].GSABulletin ,1998,110 :10 10～ 10 2 7.…     

PETROLOGY AND AGE OF THE KINNAR KAILAS GRANITE:EVIDENCES FOR AN ORDOVICIAN POST-OROGENIC EXTENSION IN THE HIGHER HIMALAYAN CRYSTALLINE, SUTLEJ, INDIA.

PETROLOGY AND AGE OF THE KINNAR KAILAS GRANITE:EVIDENCES FOR AN ORDOVICIAN POST-OROGENIC EXTENSION IN THE HIGHER HIMALAYAN CRYSTALLINE, SUTLEJ, INDIA     

YARLUNG ZANGBO OPHIOLITES,SOUTHERN TIBET REVISITED

YARLUNG ZANGBO OPHIOLITES,SOUTHERN TIBET REVISITED     

LARGE-SCALE STRAIN PATTERNS,GREAT EARTHQUAKE BREAKS,AND LATE PLEISTOCENE SLIP-RATE ALONG THE ALTYN TAGH FAULT (CHINA)

LARGE-SCALE STRAIN PATTERNS,GREAT EARTHQUAKE BREAKS,AND LATE PLEISTOCENE SLIP-RATE ALONG THE ALTYN TAGH FAULT (CHINA)     

ACCRETION OF AN EARLY CRETACEOUS INTRA- OCEANIC ISLAND ARC TO INDIA: EVIDENCE FROM THE YARLUNG ZANGBO SUTURE ZONE

ACCRETION OF AN EARLY CRETACEOUS INTRA- OCEANIC ISLAND ARC TO INDIA: EVIDENCE FROM THE YARLUNG ZANGBO SUTURE ZONE     

青藏高原北缘阿尔金东段中生代南北向伸展作用

青藏高原北缘的阿尔金山脉东段发育了延伸大于300 km、东西走向的拉配泉断裂,为南倾的正断层,局部倾角可以低至30°以下。断层中段表现为30~50 m厚的韧性剪切带,发育有较好的糜棱岩组构和矿物伸展线理;东段和西段以碎裂变形为特征。断裂带内运动学标志,如不对称香肠构造、不对称褶皱和次级脆性和韧性断裂,都指示了上盘向南的正滑移剪切方式。两方面证据控制了拉配泉断裂的活动时代。首先,拉配泉断裂上盘局部产出早-中侏罗世沉积地层。侏罗系地层中的砾石,特别是其中的含叠层石硅质灰岩和紫色石英岩,可以与断裂下盘的岩石相对比。早-中侏罗世地层可能为拉配泉断裂之上的伸展盆地沉积。其次,拉配泉断裂下盘岩石的40Ar/39Ar热年代学分析给出2个明显的冷却事件。较老的事件出现在约220~187 Ma之间的三叠纪末期至侏罗纪早期,而年轻的事件出现在早白垩世的晚期(约100 Ma).约220~187 Ma之间的冷却年龄在拉配泉断裂下盘岩石中普遍存在,代表了拉配泉断裂正断作用的主要阶段。约100 Ma时,断裂东段的正断作用再次活动,该事件可能被南倾的恰什坎正断层运动所叠加而增强,并与拉配泉断裂的东段合并。这2条断裂具有共同的上盘向南的正滑移运动方式。青藏高原和东亚其它地区的中生代伸展作用可以归结为特提斯洋向北和太平洋向西俯冲形成的弧后伸展作用。      

Mineralogical Study of Almandine-Hercynite-Muscovite-Ilmenite Hornblendite Dykes from the Southern Margin of the Gondwana Graben at Richughuta in Palamau District of the Eastern Indian Shield

正Introduction The rectangular block of Proterozoic formation lying between north of the Singhbhum Mobile Belt(SMB,2.3-2.4 Ga,Saha 1994),Neogene sediments of the Bengal basin and the Quaternary-Recent alluvium of the Ganga