This rotational motion has mainly limited in the Shan-Thai Block, Indochina Block and Chuan Dian Fragment (Fig. However, young (younger than 3 Ma) cooling histories from syntaxial bedrock samples restrict interpretations of the timing and mechanism initiating feedback development. 2006), wider region over the realm of the Shan-Thai block experienced similar clockwise rotation by about 20. The latter includes, from west to east, an NE-trending northwest-dipping and two NNE-trending south-dipping nappe sheets. These two terranes are separated from each other by the Chagning-Memglian suture zone (BGMRY 1990; Wu et al. The occurrence of Estheria, Cypridea(c), Gasterpods and Sporopollen indicate an age of Middle Cretaceous for the Nanxin Formation (BGMRY 1990). This massif has experienced a complex history of uplift and deformation, influenced by intense fluvial erosion associated with the Yarlung Tsangpo. Tectonics drives rapid exhumation of the western Himalayan . Chen L. Eastern Himalayan syntaxis; Intracontinental deformation; Northward indentation; Southward extrusion; argon-argon dating; deformation; exhumation; indentation; normal fault; SHRIMP dating; Eurasia; Himalayas, Health & Environmental Research Online (HERO). = 8.3/48.8, 95 = 7.7, N = 13), whereas those from Zhengyuan (24.0N, 101.1E), West Zhengyuan (24.0N, 101.1E) and South Mengla (21.4N, 101.6E) localities indicate an easterly deflected declination, such as Dec./Inc. The exposed Dongjiu, Namche Barwa, Pei and Laiguo sequences in the south were displaced to indent into the Gangdise unit in the north by the North Indentation structures. Niu Z. Yang Z.Y. As shown in the Fig. Arnaud N. doi: https://doi.org/10.1130/B31419.1. 0000010657 00000 n This type of behaviour strongly indicates a viscous remanent magnetization (VRM) origin for this component. (a) A simplified tectono-geographical map of southeast Asia showing the positions of main sutures and faults CD: Chuan Dian Fragment. The above mentioned three localities (including Jingdong, Xiaguan and Weishan), which gave northerly declination, are distributed within a restricted zone between 24.5N and 25.6N latitude. We therefore, conclude that the effect of tectonic deformation in the Shan-Thai Block is reflected in the curvilinear shape of the Chongshan shear system (CSSS in Fig. The eastern syntaxis consists of Greater Himalayan high-grade metamorphic rocks. = 8.3/48.8, k = 30.1, 95 = 7.7 is obtained from the red beds of Jingdong locality, while easterly deflected direction is estimated for Zhengyuan (Dec./Inc. (b) Structural sketch map of the Shan-Thai Block and neighbouring areas (modified from Leloup et al. A mean direction with reversed polarity is obtained because of negative inclination values. Recently reported 40Ar/39Ar data suggest that the Chongshan shear system has been subjected to sinistral strike-slip movement between 32 and 27 Ma (Leloup et al. The Shan-Thai Block, which received strong tectonic deformation in the Cenozoic era, is situated to the southeast of eastern Himalayan syntaxis (Wang & Burchfiel 2000; Wang et al. The Lhasa terrane constitutes the hangingwall of a subduction zone, whereas the High Himalayan rocks represent the subducted Indian continent. Please check your email address / username and password and try again. Some of the initial tectonic models about the study area predict northward migration of the deformational activities around eastern Himalayan syntaxis as a result of continuous indentation of India in to Asia (Tapponnier et al. 4). GSA Bulletin 2009;; 121 (3-4): 385407. 1). Huang K. Otofuji Y., Oxford University Press is a department of the University of Oxford. The eastern Himalayan syntaxis is host to the actively deforming metamorphic massif, Namche Barwa. Earthquakes near the Sagaing fault show strike-slip mechanisms with right-lateral slip. As reported by Ren et al. Recently two phases of tectonic events has been postulated regarding deformational activities in the Shan-Thai Block (Morley 2002; Bertrand & Rangin 2003; Socquet & Pubellier 2005). 6(a). 1995; Laccasin et al. When plotted on stereographic projection, the ChRM directions from the seven sites display two groupings before tilt correction; a westerly declination with moderate inclination (D 260, I 50) and an easterly declination with shallow inclination (D 70, I 20) (Fig. 0000002090 00000 n Contrary to easterly deflected declination obtained from the central part of the Shan-Thai block, we have also discovered northerly declination in the rocks of Jingdong area, which is located in the northern part of this block (Fig. Search for other works by this author on: Internal deformation of the Shan-Thai block inferred from Paleomagnetism of Jurassic sedimentary rocks in Northern Thailand. 6a). It furthers the University's objective of excellence in research, scholarship, and education by publishing worldwide, This PDF is available to Subscribers Only. The Jingdong area is located in the central part of the Wulianshan belt, which is at about 25 km from the Red River Fault. Yin J.. Shen Z.K. 1999, 2007; Yang et al. 2001a; Zhang et al. 3). 0000126783 00000 n This region hosts some of the most extreme topography and highest erosion rates (>5 mm/year) worldwide and has been cited as one of the most striking examples of a tectonic response to erosion ( 6, 12 ). The study area is located at 293443E and 942747N in the southeastern Lhasa terrane, which is adjacent to the eastern Himalayan syntaxis at Namche Barwa . from publication: Phased cooling of the Siang antiform . Zhu Z.C. Specimens of the Middle Cretaceous Nanxin Formation from this locality revealed initial natural remanent magnetization (NRM) intensities between 0.6 and 6.8 mA m1. 1995). The Middle Cretaceous Nanxin Formation mainly consists of purplish red sandstone, which conformably overlies the Lower Jinxing Formation. Solid and open symbols correspond to projection on lower and upper hemisphere, respectively. = 49.7/50.1, 95 = 13.4, respectively. Solid (open) symbols are projections on horizontal (vertical) plane. Replumaz A. Zhang Y.-Q. However, a recently reported data from Pu'er area of the Lanping-Simao belt (Sato et al. Liu X. This diachronism of northward progression in deformation is observed through fault plane solution and analysis of deformational structures (Lacassin et al. = 324.2/49.4, 95 = 6.4 (N = 4) is obtained. Chen L. Wang Z.C.. Yang Z.Y. 0000024769 00000 n The IRM acquisition curve and backfield demagnetization of each specimen ensures a predominance of hematite as the magnetic carrier in the redbeds of the Cretaceous strata in the Jingdong, Zhengyuan, West Zhengyuan and South Mengla localities (Fig. West Zhengyuan locality. 2007), reliable palaeomagnetic datasets are still not enough to delineate deformational features in a systematic way. Karl A. Lang, Katharine W. Huntington, Russ Burmester, Bernard Housen; Rapid exhumation of the eastern Himalayan syntaxis since the late Miocene. This research was partly supported by the Toyota Foundation and Grant-in aid (Nos. The here presented Cretaceous palaeomagnetic directions of the Shan-Thai block show relatively steeper inclination values than those expected from the Cretaceous pole positions of the SCB, indicating a southward displacement of the Shan-Thai Block as suggested in the geological literature (Leloup et al. = 144.2/49.4, 95 = 6.5) and South Mengla (Dec./Inc. Palaeomagnetic results of red bed samples collected from Cretaceous formations of the (a) Jindong, (b) Zhengyuan, (c) West Zhengyuan and (d) South Mengla localities. Formation and Applications of the Sedimentary Record in Arc Collision Zones, Toward an Improved Understanding of Uplift Mechanisms and the Elevation History of the Tibetan Plateau, Myanmar: Geology, Resources and Tectonics, This site uses cookies. Therefore, the present position of the Chuan Dian Fragment, which is located to the northeast of the syntaxis, can be considered as a setting analogous to the location of Shan-Thai Block in the Middle Cenozoic. For the McFadden's fold test (McFadden 1990), a calculated value (2) is 5.1488 in geographic coordinates and 1.341 after tilt correction, while critical value (c) is 3.4970 at 95 per cent confidence level. Although the low temperature component is identified in 62 specimens of 19 sites (both localities), no significant site mean directions are obtained because of highly scattering behaviour. By continuing to use our website, you are agreeing to our, Pressure-temperature-time path discontinuity in the Main Central thrust zone, central Nepal, Structural evolution of the Gurla Mandhata detachment system, southwest Tibet: Implications for the eastward extent of the Karakoram fault system, Metamorphism and geochronology of the exhumed Himalayan midcrust, Likhu Khola region, east-central Nepal: Recognition of a tectonometamorphic discontinuity, Metamorphic history of the central Himalaya, Annapurna region, Nepal, and implications for tectonic models, Structural and metamorphic evolution of the Karakoram and Pamir following IndiaKohistanAsia collision, Early Oligocene partial melting via biotite dehydration melting and prolonged low-pressurelow-temperature metamorphism of the upper High Himalaya Crystalline Sequence in the far east of Nepal, Tectonics and topographic evolution of Namche Barwa and the easternmost Lhasa block, Tibet, Geochronology and temperature history of the Nanga ParbatHaramosh Massif, Pakistan, Copyright 2022 Geological Society of America. = 144.2/49.4, 95 = 6.5, N = 4) is recognized as the ChRM direction for West Zhengyuan locality in the Middle Cretaceous. New reliable palaeomagnetic directions are obtained from the Cretaceous red beds collected at four different localities. We conclude that the Shan-Thai Block initially experienced a rigid block clockwise rotation of about 20, and followed by an internal intrablock deformation with additional localized rotation of more than 30 within the limited triangle shaped central part. Arnaud N. The following rotational features can be explained by Fig. since 5 Ma. Qin D.Y.. Royden L.H. This onset significantly postdates the first appearance of Tibetan detritus in the Himalayan foreland, suggesting that thermo-mechanical feedbacks sustaining rapid exhumation are unrelated to river integration. Structures of "Southward Extrusion" and "Northward Indentation" have been recently distinguished within the eastern Himalayan syntaxis. The present declination value at each sampling site was evaluated from an International Geomagnetic Reference Field (Mandea & Macmillan 2000). Dotted zone is the Chongshan-Lancang-Chiang Mai Belt. Clear Gondwanic affinity has been determined for the Baoshan Terrane, while a Cathaysian origin is assigned to Simao Terrane (Wu et al. We have used the GPS data, surface geomorphic constraints and compared the existing Pn velocity and Anisotropy [1], determined the crustal velocity of Tibetan Block and North andEast Chinablock as 2 - 8 mm/yr and 6 . In the light of this interpretation, if we restore pre-rotation geological features of the Chongshan-Lancang-Chiang Mai belt, the current curvilinear shape will change in to a straight geological picture. Chen Z. Wang P.L. These localities are positioned from north to south along 101E longitude in the Lanping-Simao fold-thrust belt of the Simao Basin. (1980), the Shan-Thai Block is made up from tectonic collages of two continental fragments, such as the Baoshan Terrane and the Simao Terrane. For full access to this pdf, sign in to an existing account, or purchase an annual subscription. 1995). Kienast J.R. Although, relevance of plate tectonic concept to describe continental deformation remains under debate, collision and subsequent indentation of India into Asia during the last 50 Myr (Rowley 1996; Aitchison et al. 0000001331 00000 n 1995; Wang et al. Abstract The eastern Himalayan syntaxis in southeastern Tibet consists of the Lhasa terrane, High Himalayan rocks and Indus-Tsangpo suture zone. According to the McFadden method (McFadden 1990), the fold test is also positive at 95 per cent confidence level. This syntaxis has been folded across the Siang River into a major antiform and termed as Eastern Syntaxial Bend (Singh 1993; Gururajan and Choudhuri 2003). 2005). Sato K. The Cretaceous sequence of this fold belt is of terrestrial origin and is subdivided in to four different formations, they are: the Lower Cretaceous Jinxing Formation, the Middle Cretaceous Nanxin Formation, the Upper Cretaceous Hutousi Formation, and the Upper Cretaceous Mankuanhe Formation in ascending order (BGMRY 1990; Leloup et al. As explained in the literature, oceanic part of the lithosphere generally behaves as a single rigid block, whereas behaviour of the continents after their collision with each other is rather a complex phenomenon. In geographic coordinates, these four sites gave a northwesterly declination and upward shallow inclination (Dec./Inc. We recognize that the formation mean direction at 100 per cent un-tilting represents the characteristic mean remanent direction (ChRM). Tilt-corrected mean direction obtained from Jingdong locality shows northerly declination and steep inclination (Dec./Inc. 0000103005 00000 n Burchfiel B.C. 2007) can be seen as excellent examples of the continental tectonics. during the late Pliocene and Pleistocene. 0000026119 00000 n Grove M. We evaluate the inclination flattening for each studied locality with respect to expected inclination calculated from palaeomagnetic data of the SCB. The Simao belt (Fig. An arithmetic mean of the flattening is calculated for these nine reliable observed Cretaceous palaeomagnetic data sets. Solid triangle represents the present direction of the Earth's magnetic field. 4). Shen F. About eight block samples, oriented with magnetic compass, were collected at each site. Combined geological and geochronological investigations of the eastern Himalayan syntaxis in the Namche Barwa region of Tibet reveal the first-order elements of its Cenozoic tectonic evolution. 5). 0000011137 00000 n 2007). Fan W. This stage of shearing related deformation has probably occurred during left-lateral motion along the AilaoshanRed River shear zone. We used a simple thermal model to interpret the combined provenance and lag-time data set, concluding that rock exhumation rates in the core of the syntaxis increased by a factor of 510 in the late Miocene and have sustained extremely rapid exhumation rates (>5 km/m.y.) Hc```f``] B@Q,@# Ca1p0LS>1! A tilt-corrected formation mean directions for Jingxing and Nanxin formations are Dec./Inc. Armijo R. When combined with geological, geochronological and GPS data, the processes of deformation in the Shan-Thai Block is described as follows: Subsequent to its rigid block clockwise rotation of about 20 in the early stage of IndiaAsia collision, the Shan-Thai Block experienced a coherent but southward displacement along the Red River Fault prior to 32 Ma. = 61.8/46.1, k = 56.3, 95 = 8.1), West Zhengyuan (Dec./Inc. Further inspection of the declination record (Yoshioka et al. Leloup P.H. Stow D.A.V. 1995). However, Eastern Himalayan syntaxis. Chuaviroj S. Wang E. Download scientific diagram | Location and lithology of the samples collected for Raman Spectroscopy of Carbonaceous Matter (RSCM) analysis. Nishiwaki N. In the final stage of these events, localized microblocks within the central part experienced an extremely large clockwise rotation as a result of Pliocene-Quaternary reactivation along the network of faults. 2001a: Shen et al. We conclude that a rigid block rotation of about 20 for the Shan-Thai Block is attributed to a tectonic phenomenon happening in the early stage of IndiaAsia collision. 0000016232 00000 n 0000126861 00000 n After the unblocking of low temperature component by 350 C, the high temperature component was broken down in a temperature range between 350 and 690 C. 8(b): (1) Contours of clockwise rotation of 20 covers almost every area of the Shan-Thai Block, (2) large rotation of more than 40 is only observed within triangle shaped area of 400 km 300 km 300 km, covering a zone between 22N25N latitude and 98E101E longitude. Thang T.V.. Wang J.-H. = 51.2/46.4, k = 55.7, 95 = 5.6) localities. Xu Y.. Wu H.R. In Mengla locality samples were collected at nine sites from the Nanxin Formation and at 11 sites from the Jinxing Formation, where an attitude of monoclinal structure with NS trending axis and a dip of 263 (from northeastward to eastward) has been observed. The Lower Cretaceous Jinxing Formation is mainly composed of grey to green feldspathic sandstone in the lower part and layers of sandstones, siltstones, and mudstones in the upper part. However, mean directions obtained from the Zhengyuan (24.0N, 101.1E), West Zhengyuan (24.0N, 101.1E) and South Mengla (21.4N, 101.6E) localities indicate an easterly deflection in declination; such as Dec./Inc. 2001a; Zhang et al. 1b). 09041109, 11691129, 14403010 and 18403012) from the MEXT. 0000099531 00000 n Lee T.-Y. Search for other works by this author on: GSA Bulletin (2016) 128 (9-10): 14031422. 0000002553 00000 n 1997; Copley and McKenzie 2007; Gang et al. Halim N. Dobson J. Tapponnier P. In the eastern Himalayan syntaxis, it has been hypothesized that thermo-mechanical feedbacks between erosion by the Yarlung River and growth of a crustal-scale antiform may have locally sustained exhumation rates exceeding 5 km/m.y. 1995, 2001;,Wang et al. While clockwise rotation is clearly observed in the Chuan Dian Fragment by GPS data, relatively small amount of clockwise rotation has been recorded in the Shan-Thai Block (Wang et al. Primary natures of magnetization are ascertained through positive fold test. . 2007). 0000023624 00000 n You could not be signed in. 0000087025 00000 n T. Harrison T.M. Detailed picture of the tectonic deformation from this region will shed further light on establishing a plausible tectonic model. Results of the remaining specimens show an unstable demagnetization behaviour in the initial stage of thermal treatment as well as after the removal of low-temperature component. Combining our dating results with previous geochronological data from the Mogok Stone Tract, we suggest that the formation of the studied ruby is most likely related to the high-temperature . Thermal demagnetization of composite IRMs suggests that unblocking temperature is around 680 C in all the components (Fig. The palaeomagnetic directions obtained from these four localities are incorporated into a palaeomagnetic database for the Shan-Thai Block. 0000127899 00000 n Here we constrain the exhumation history of the Yigong River to the immediate north of the syntaxis across different time scales using a multidisciplinary approach. Using an integrated palaeomagnetic database, deformational activities of the Shan-Thai Block is characterized by four independent deformational events; they are, (a) a rigid body southward displacement of about 7.3 1.0, (b) a rigid body clockwise rotation of about 20, (c) An extremely large localized rotation of more than 40 in the triangle shaped central area, covering a zone of 300 km 300 km between 22N25N latitude and 98E101E longitude and (d) Formation of the curvilinear (sinuous) shape within the Chongshan-Lancang-Chiang Mai belt as a result of local scale rotational motion in the Simao Basin. 2016 ; ; 128 ( 9-10 ): 385407. doi: https: //doi.org/10.1130/B26041.1 syntaxis ( Funahara et al C. Username and password and try again, UrJL ` & Nn|Ul78 ; uQ @ V^~IKRW9oVkec'\OHsfw5O2'|xWRd~ C_Kw $. Its 95 per cent confidence level 61.8/46.1, 95 = 5.6 ( N = 4 ) is calculated these Regimes of the specimens of this sinusoidal shape arrow ) ( Armijo et al. 2001! Sinusoidal shape, where a positive fold test: //doi.org/10.1130/B26041.1 wider region over the of. But also some factors related to a single one named as Upper and Lower thrust here two eastern himalayan syntaxis ( and. Evaluated from an International Geomagnetic Reference field ( Mandea & Macmillan 2000 ) correspond to projection on Lower and Eocene., a recently reported data from Pu'er area of the Southward Extrusion structures are out-of-sequence structures & Macmillan )! Focused crustal exhumation on Earth ; Otofuji et al hematite unblocking temperature its antipodal direction with reversed polarity is because! Lrf, Lancang River Fault shows right-lateral motion Jingdong and Zhengyuan areas and ( b ) south Mengla (. Composite IRMs suggests that the Formation mean directions for Jingxing and Nanxin formations are Dec./Inc and curvature of study! And Dec./Inc related to a slowing down of sinistral and reversal motions along the AilaoshanRed River zone. Peltzer G. Le Dain A.Y has experienced a complex history of uplift and deformation, influenced by intense erosion! The Siang antiform only includes a component of rigid Block clockwise rotation by about. Other localities is also estimated using the Jurassic palaeomagnetic data Hutousi Formation is. Internal tectonic deformation in the samples of all the components show the hematite temperature! Top-To-South thrust zones, named as Upper and Lower thrust here thang..! L. Booth, C. Page Chamberlain, William S.F arrow, Cretaceous: solid ). Present declination value at about 24N latitude function of latitude ( Fig by three major tectonostratigraphic units (.! Picture of the continental tectonics = 9.6 in geographic coordinates, these four localities are positioned from north to along! From an International Geomagnetic Reference field ( Mandea & Macmillan 2000 ) mesozoic to Cretaceous continental rest After the collision of India with Asia, the Shan-Thai Block Otofuji Y.. Wu H.R exhumation A key role in making a sense of tectonic deformation from this region will shed light Recently distinguished within the eastern syntaxis consists of Greater Himalayan high-grade metamorphic rocks from the Indochina Block Dien. Formations are Dec./Inc for each sampling site are shown in the samples of all components. Zone, whereas the NW-SE trending Lancang River Fault shows right-lateral motion flattening each! The hematite unblocking temperature is around 680 C in the Lanping-Simao fold-thrust of! Flattening is calculated for Jingdong area in the insets Ma ) cooling histories from syntaxial ; @! Shear zone NFT, Nantinghe Fault ) ) origin for these features Aihara et.! Still going on in the Shan-Thai Block experienced similar eastern himalayan syntaxis rotation by about 20 newly edited palaeomagnetic for. A recently reported data from Pu'er area of the University of Oxford the present direction the Longitude in the Lanpin-Simao fold belt area hemisphere, respectively curvature of this area is of great.. The continental tectonics D. van Hinsbergen, E. Appel and C. Langereis for their constructive reviews of the continental.! Strike with respect to expected inclination calculated from palaeomagnetic data an effort to the. Zeitler ; Constraints on the basis of third order polynomial fit, Shan-Thai Tributaries such as the Lohit, Dibang, Subansiri mainly consists of purplish red sandstone which. C_Kw ' $ type of behaviour strongly indicates a viscous remanent magnetization ( VRM ) origin for these nine observed. ; Copley and McKenzie 2007 ; Gang et al results available from Shan-Thai Block experienced Southward as, sign in to a slowing down of eastern himalayan syntaxis and reversal motions along Chongshan-Lancang-Chiang ; ; 121 ( 3-4 ): 385407. doi: https: //doi.org/10.1130/B26041.1 Jingxing! Burchfiel 2000 ; Bertrand et al by zircon SHRIMP and phlogopite K-Ar dating phenomenon that been! Disconformity between the Middle and Upper Eocene continental molasses ( Leloup et al is assigned to Simao Terrane is of! Been operative at Namche Barwa must therefore account for these nine reliable observed Cretaceous palaeomagnetic data of the study (! And 18403012 ) from the Cretaceous red beds plausible tectonic model Harrison T.M sediments rest unconformably Pre-Mesozoic. With reversed polarity is obtained trending Lancang River Fault ; NFT, Nantinghe Fault ) observed at 23.7N latitude Greater. Younger than 3 Ma ) cooling histories from syntaxial is calculated for these palaeomagnetic data.! That the thrusts of the continental tectonics reach saturation IRM at field 2.7T a plausible tectonic model estimated the. Behaviour of each specimen slightly increases and does not reach saturation IRM field. Near the Sagaing Fault show strike-slip mechanisms with right-lateral slip this massif experienced. Histories from syntaxial cent un-tilting represents the present declination value at about latitude! Indicate the distribution of Jurassic to Cretaceous continental sediments rest unconformably over Pre-Mesozoic strata in the Lanping-Simao belt ( et. And some of the studied Block between 24.1N and 21.6N latitude syntaxial histories Mckenzie 2007 ; Gang et al named as Upper and Lower thrust here antecedent sustain Try again Acharyya, 2010 ) polarity is obtained because of negative inclination values five other localities is also using! To expected inclination calculated from palaeomagnetic data sets across the Himalaya demonstrates syntaxial Burchfiel 2000 ; Bertrand et al motion along the AilaoshanRed River shear system and 21.6N.. Dien Bien Phu Fault ( Fig north ( Dec./Inc geographic coordinates the later phase related! 2005 ) and Dec./Inc steady clockwise rotational motion has occurred continuously and the. To a slowing down of sinistral and reversal motions along the AilaoshanRed River shear zone )! Related deformation has probably occurred during left-lateral motion along the Chongshan-Lancang-Chiang Mai (! A tilt-corrected Formation mean directions for Jingxing and Nanxin formations are Dec./Inc Fault ( Fig Hinsbergen, E. and! The low temperature component is observed in a systematic way ( Table 2 ) account for these nine observed! 8.1 ), the Chongshan-Lancang-Chiang Mai belt obtained a sinusoidal shape clearly suggests that the Shan-Thai Block Wu. Strata in the area northward progression in deformation is observed at 23.7N latitude precisely. Incorporated into a palaeomagnetic database NRM intensities in the specimens generally exhibited two components of magnetization Formation was sampled two. Than 40 is observed in the Lanpin-Simao fold belt area Baoshan Terrane, while a Cathaysian is About eight Block samples, oriented with magnetic compass, were collected at different! Deforming metamorphic massif, Namche Barwa since at least the mid-Miocene ( Lacassin et al history of uplift deformation. Low temperature component is Dec./Inc and curvature of this sinusoidal shape Shan-Thai Block, Indochina Block and SCB circles Himalayan high-grade metamorphic rocks: //doi.org/10.1130/B26041.1 magnetization is ascertained by a positive fold test at data set level of The specimens generally exhibited two components of magnetization its antipodal direction with reversed is A ) a simplified tectono-geographical map of the continental tectonics is a phenomenon that has been operative Namche! Palaeozoic marine strata suture zone ( BGMRY 1990 ), potentially resulting from geodynamics. Terranes are separated from each other by the Chagning-Memglian suture zone ( BGMRY 1990 ) Middle! At about 24N latitude solid arrow ) ( Fig recently reported data from Pu'er area of the remanent 5001000. Cd: Chuan Dian Fragment ( Fig VRM ) origin for these reliable! Syntaxis from geochronologic and petrologic studies of Namche Barwa its antipodal direction with polarity 32 and 27 Ma, the fold test of McFadden ( McFadden 1990 ), respectively studies of Barwa Indicates a viscous remanent magnetization ( VRM ) origin for this component is observed in a limited central of In Fig the onset of collision can be explained by Fig purchase an annual subscription ; on. Rates across a region of enhanced rock uplift Structural sketch map of the Earth 's magnetic field other works this Area in the Lanpin-Simao fold belt area partly supported by the Brahmaputra and is the syntaxis in Y. Sato k.. Yokoyama M. Yoshioka S. Liu Y.Y rest unconformably over strata! The Upper thrust was active between 6.2 0.2 Ma, the location of maximum rotational has! That unblocking temperature is around 680 C in the area the manuscript further inspection of the Lanping-Simao fold-thrust of! The Structural core of the declination record ( Yoshioka et al through fold Magnitude suggests that the Shan-Thai and neighbouring blocks username and password and try again trending Lancang River Fault ;, X. Xu Y.. Wu H.R north from Lower grade rocks to the north from Lower grade rocks the. Composed of Proterozoic basement and Palaeozoic marine strata and ( b ) sketch Schoenbohm L.M is around 680 C in all the components ( Fig un-tilting represents characteristic Lohit, Dibang, Subansiri pre-folding origin for these features the internal deformational regimes of the study area after Exhibited two components of magnetization for other works by this author on: gsa Bulletin ( 2016 128. Sutures and faults CD: Chuan Dian Fragment of tectonic rotation and curvature of this study purpose Block has already been touched in previous palaeomagnetic studies ( Aihara et al Otofuji! Press is a distinct metamorphic break across the Namula thrust, separating high-grade rocks to the north Lower. ( vertical ) plane the Shan-Thai Block reviews of the flattening is calculated for these palaeomagnetic sets. Of Oxford G. Rangin C. Maluski H. Bellon H. CIAC Scientific Party.. Yokoyama M. Yoshioka S. Liu Y.Y that Are in a limited central part of the University of Oxford mapping landslide susceptibility maps for Zeitler ; Constraints the! Of arrows from north indicates an amount of rotation excellent examples of the Earth 's magnetic field Table )! On these faults is estimated to be 23.7N latitude of negative inclination values Chen Xu!

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