South Altyn Tagh Research Articles

Cenozoic evolution of the Altyn Tagh and East Kunlun fault zones inferred from detrital garnet, tourmaline and rutile in southwestern Qaidam Basin (Northern Tibetan Plateau)

AbstractThis study focuses on the Cenozoic provenance and tectonic evolution of the southwestern Qaidam Basin through geochemical analysis of detrital garnet, tourmaline and rutile. The variation of detrital mineral compositions indicates that the Cenozoic evolution can be divided into three stages: (i) before the deposition of the upper Xiaganchaigou Formation (before 37.8 Ma); (ii) between the deposition of the upper Xiaganchaigou Formation and the Shangganchaigou Formation (from 37.8 to 22 Ma); (iii) since the deposition of the Xiayoushashan Formation (since 22 Ma). In the first stage, abundant garnets from high‐grade meta‐basic and ultramafic rocks in the sediments from the Ganchaigou area support a provenance from the South Altyn Tagh HP/UHP metamorphic zone. The low percentage of tourmalines from granitoid rocks in the sediments in the Kunbei‐Lücaotan area suggests a provenance from the East Kunlun fault zone, indicating that the Qimen Tagh Shan was not high enough to prevent the transport of sediments from the southern Qaidam Basin. The sediments in the Qigequan area were derived from both the Altyn Tagh fault zone and the East Kunlun fault zone. In the second stage, the tectonic activity consisted in the rapid uplift of the Altyn Shan. Changes in garnet composition indicate a lower detrital contribution from high‐grade metamorphic rocks. In the third stage, the disappearance of garnets from high‐grade metamorphic rocks and scattered temperatures of rutiles in the Ganchaigou area suggest that the source area shifted from the South Altyn Tagh HP/UHP metamorphic rocks to weakly metamorphosed Meso‐Neoproterozoic sedimentary rocks. The increase in granitoid‐derived tourmalines in the Kunbei‐Lücaotan area is indicative of the rapid uplift of the Qimen Tagh Shan. The provenance evolution in the southwestern Qaidam Basin indicates that the tectonic activity along the Altyn Tagh fault zone can be divided into an early stage of Altyn Shan uplift and a later stage of left‐lateral slip. At the same time, tectonic movement along the East Kunlun fault zone initiated.

The paleotectonic and paleogeography reconstructions of the Tarim Basin and its adjacent areas (NW China) during the late Early and Middle Paleozoic

Tarim Basin is the large, very complex, oil-bearing basin in China, surrounded by the Tianshan–Beishan, West Kunlun and Altyn Tagh mountain belts to the north, south, and southeast, respectively. Understanding the processes and evolution of this complex superimposed basin, especially with respect to the effects of single tectonic movements, is a difficult challenge, which concerns the tectonic and dynamic interrelationships between the basin and the orogenic belts during the different stages of the Paleozoic in the Paleo-Asian and Tethyan tectonic systems and for the evaluation of the resource potentials in Tarim Basin. In this study, we focused on 3-dimensional, basin-scale structural architecture and the properties of two regional unconformities that occur within the basin and its adjacent areas. Here, we outline the structural deformations underlying the unconformity, the structural architecture styles and the distributions of the unconformity, and the stratigraphic sequence and nature of the sedimentary rocks immediately overlying the unconformity. During the late Early and Middle Paleozoic tectonic movements, disconformities developed mainly in the northern and the central parts of the basin, and angular unconformities which beneath layers were monocline and faulted-fold deformations developed in the southern, or the southern and northern parts of the basin, respectively. Before the Silurian, the Low Hotian Uplift, the NE-trending faulted-folded belts of the Tangguzibas Depression and the southern Tazhong Uplift underwent intense deformation related to SE–NW-directed tectonic compression. In addition, the NE-trending faults in the Tangguzibas Depression developed during periods of activity on the South Altyn Tagh Fault. The structural deformation, as well as the depositional facies, formed in response to the subduction and closure of the South Altun Ocean and West Kunlun–Kudi Ocean, and the resulting collisional orogeny. Prior to deposition of Upper Devonian sediments, structural deformation and erosion occurred in two marginal parts of the basin. The extent and intensity of deformation on the NE-trending faults in the Tangguzibas Depression were also reduced, whereas the NE-trending folds developed in the Manjiaer Depression. The Tabei Uplift experienced uplift and deformation. The closure of the North Altun Ocean and the eastern part of the South Tianshan Ocean with south-subduction may be the main driving forces for the tectonic activity. Extensive areas in the northern and southern margins of the basin were uplifted and denudated by orogenic activity as a prelude to the molasse basin that developed in the early Late Devonian in the northeastern and southeastern parts of the basin. The structural architecture of the unconformities reveals the geometry and dynamics of the basin–orogen system in single tectonic movements.

Age, petrogenesis and tectonic implications of Early Devonian bimodal volcanic rocks in the South Altyn, NW China

In this paper, we report zircon U–Pb dating, Hf isotopes, geochemical and Sr–Nd isotopic data, with the aim the petrogenesis and regional tectonic evolution of Early Devonian bimodal volcanic rock in the South Altyn, NW China. New LA-ICPMS zircon U–Pb isotopic data constrained them at ca. 406Ma. The mafic samples are characterized by high Fe, Cr and Ni contents, low Ti and Mg contents, slightly enriched LREE patterns, and low (La/Yb)N, La/Nb and La/Ta ratios, and positive εNd(t) values (+3.3 to +3.4), indicating that they were likely derived from strong batch-melting of the asthenosphere in the spinel facies field. The felsic rocks show an A-type affinity, with high alkalis, Fe, Ga, Zr, Nb, Ce and Y contents, low Mg, Sr content, high Rb/Sr and Ga/Al ratios, enrichment in LILE (e.g., Rb, K, Th, U and LREE) and depletion in Ba, Sr, Nb, Ta, P and Ti, and fractionated REE patterns with very strong negative Eu anomalies. These features, along with distinct εNd(t) values (−0.5 to +2.3) and mostly positive εHf(t) (−0.29 to +5.18), indicate that the felsic rocks were mainly generated by partial melting of the crust in low pressure and high temperature conditions, and simultaneously underwent slight magma mixing of such melts with mantle magma. According to the petrogenetic schemes and geological background of the Early Devonian bimodal volcanic rocks (tholeiite and A-type dacite–rhyolite), they should have formed in a post-collisional extensional setting. Moreover, on the basis of spatial and temporal distribution, and formation mechanism, the tectonic magmatic evolution of the early Paleozoic South Altyn Tagh could be divided into three stages: ① 505–472Ma (continental collision), the magmatite formed under high-pressure conditions due to the deep subduction and initial tearing of continental slab; ② 467–450Ma (continental slab break-off), the magmatite formed at high temperature and low pressure in virtue of felsic upper crust uplifting and mantle magma underplating; and ③ 432–385Ma (post-collisional extension), the magmatite consists of A-type granites and bimodal volcanic rocks, which are the products of the interaction between mantle and crust, and asthenosphere upwelling.

Origin of Early Paleozoic garnet peridotite and associated garnet pyroxenite in the south Altyn Tagh, NW China: Constraints from geochemistry, SHRIMP U–Pb zircon dating and Hf isotopes

Garnet peridotite, garnet pyroxenite, mafic granulite and dominant felsic granulite constitute a high-pressure/high-temperature (HP/HT) metamorphic terrane in the south Altyn Tagh, North Tibet (China). Garnet peridotite and associated garnet pyroxenite occur as slices or lenses within high pressure felsic granulite. Previous studies indicate that garnet peridotite experienced the peak HP/HT metamorphism, followed by a medium pressure granulite-facies overprint. However, the origin of the garnet peridotite and associated garnet pyroxenite remains controversial. In this contribution, we present new zircon U–Pb and Hf isotopic data and whole-rock major, trace element and Sr–Nd isotopic data for the representative garnet peridotites and associated garnet pyroxenites. SHRIMP U–Pb dating on the inherited (magmatic) zircons from the garnet peridotites gave an U–Pb age of ca. 780Ma, which is interpreted as the age of the ultramafic magma crystallization. The metamorphic zircons yield an age of ca. 500Ma, which is consistent with the Sm–Nd isochron age of 493±24Ma for whole rock, garnet and clinoproxene from a garnet pyroxenite, representing the timing of peak metamorphism. The Baishiwake garnet peridotites and garnet pyroxenites show relatively high contents in Fe2O3, TiO2, P2O5, Nb, Zr, and Y, but significantly low MgO, Cr, A12O3 and Ni contents. They possess enriched LREE, nearly flat HREE, slightly positive Eu anomaly and weak negative anomalies in Nb and Ti. The relatively high 87Sr/86Sr ratios (0.707–0.710) and low 143Nd/144Nd ratios (0.5123–0.5124) imply a possible crust contamination prior to HP metamorphism. Integrating these data together with previous studies, we suggest that the Bashiwake garnet peridotites and associated garnet pyroxenites were derived from mantle-derived magmas which intruded into the continental crust during the Neoproterozoic and then experienced a common HP/HT metamorphism with felsic crustal rocks in the Early Paleozoic (ca. 500Ma).

Geochemistry and Zircon U-Pb Dating of Changshagou Adakite from the South Altyn UHPM Terrane: Evidence of the Partial Melting of the Lower Crust

Changshagou adakite, an outcrop in the middle segment of the South Altyn Tagh ultra-high pressure metamorphism (UHPM) terrane, contains medium-K cal-alkaline and weakly peraluminous compositions (SiO2= 66.79% to 68.65%, Al2O3= 17.48% to 18.31%, K2O + Na2O = 6.32% to 6.88%, K2O/Na2O = 0.25 to 0.33, A/CNK = 1.01 to 1.06). This outcrop is also enriched with large ion lithophile elements but with depleted high-field strength elements (HFSE) showing clearly negative Nb, Ta, and Ti anomalies. REE distribution patterns show a positive anomaly of Eu (δEu = 1.15 to 1.31) and weakly enriched with LREE compared with HREE (LREE/HREE = 1.02 to 4.20). Experimental results and several characteristics, including relatively low Nb/Ta ratios (6.03 to 8.45) and high Sr, Sr/Y, (La/Yb)N and low Y and Yb, which indicate the presence of residual garnet and the absence of plagioclase in the source region, show that adakite may form at a pressure ranging from 1.2 GPa to 1.5 GPa and at a temperature of approximately 900°C. Low Cr, Ni, and Mg# values, trace element patterns, and SiO2–Mg# and SiO2–MgO diagrams indicate that rocks are formed by the partial melting of a thickened lower continental crust LA-ICP-MS in situ U-Pb dating yields two group ages: 503.1 ± 1.7 Ma (core) and 453.1 ± 3.0 Ma (rim). The Th/U ratios of the core and the rim are 0.11 to 0.40 and 0.03 to 0.07, respectively. Considering the zircon CL image characteristics, Th/U ratios, and previous studies on regional UHPM rocks, adakite formed at 503.1 ± 1.7 Ma and underwent a tectothermal event as a result of the break-off of the Altyn deep subducted continental crust at 453.1 ± 3.0 Ma.

Combined rutile–zircon thermometry and U–Pb geochronology: New constraints on Early Paleozoic HP/UHT granulite in the south Altyn Tagh, north Tibet, China

Abstract HP granulite and garnet peridotite constitute a HP metamorphic unit in the south Altyn Tagh, northern Tibet. Previous data suggest that HP granulites experienced high pressure, ultrahigh-temperature metamorphism (870–1050 °C, 19–25 kbar), followed by a medium pressure granulite facies overprint (780–820 °C, 9.5–12 kbar). Previous zircon U–Pb geochronology of HP granulites gave an age of ca. 500 Ma, but it is unclear if this age reflects the metamorphic peak, or the post-peak overprint. In this contribution, new SHRIMP analyses indicate that the zircons associated with the peak metamorphic assemblage in HP felsic granulite are characterized by flat heavy REE patterns and 30–62 ppm Ti, yielding a temperature of 892–1002 °C by Ti-in-zircon thermometry, suggesting that the growth of the zircons occurred under or close to peak ultrahigh-temperature conditions rather than under post-peak conditions. These zircons gave a SHRIMP U–Pb age of 495 ± 4 Ma, representing the age of peak metamorphism. In contrast, oscillatory zoned zircon cores yield magmatic REE patterns, Ti-in-zircon temperatures of 720-820 °C, and Neoproterozoic U–Pb ages (936 ± 22 Ma). This indicates that the protoliths of the felsic granulites were formed in the early Neoproterozoic and were taken to extreme temperatures and pressures during the early Paleozoic orogenic event. In situ LA-ICPMS and EMP analyses indicate that rutiles are characterized by broad scatter and bimodal distribution in both Zr concentration and U–Pb age, which are interpreted as a result of recrystallization or growth rather than volume diffusion. The first rutile U–Pb age cluster is at ca. 485 Ma with a Zr concentration of ca. 3000 ppm, yielding ca. 950 °C at 20 kbar, implying that they grew at or near the peak metamorphic conditions. The second rutile U–Pb age cluster is at ca. 450 Ma with a Zr concentration of ca. 1000 ppm, corresponding to a temperature around 780 °C at 10 kbar, which is related to post-peak reheating under medium pressure/medium temperature granulite facies conditions. These results demonstrate that HP granulites in the south Altyn Tagh experienced a peak ultrahigh temperature and high pressure metamorphism at ca. 495 Ma, followed by medium pressure/medium temperature granulite facies overprint before ca. 450 Ma.

Progress and controversy in the study of HP-UHP metamorphic terranes in the West and Middle Central China orogen

During the past ten years, various types of HP-UHP metamorphic rocks have been discovered in the South Altyn Tagh, the North Qaidam and the North Qinling (秦岭) in the West and Middle Central China orogen. The UHP rocks, as lentoid bodies in regional gneisses, include eclogite (garnet-bearing pyroxenite), garnet peridotite and various pelitic or felsic gneisses. There are many records of minerals and microstructures of exsolution indicate the UHP metamorphism, such as coesite (or its pseudomorph), diamond, exsolution of clinopyroxene/amphibole/+rutile or rutile+quartz+apatite in garnet, exsolution of quartz in omphacite and exsolution of kyanite+spinel in precursor stishovite. The discovery of microstructure evidence for the presence of precursor stishovite in typical Alrich gneiss from the South Altyn Tagh reveals continental subduction and exhumation to and from a depth of more than 350 km. It is the petrological record of the deepest subduction and exhumation of continental rock in the world. The in situ zircon U-Pb dating using LA-ICP-MS or SHRIMP methods shows that the metamorphic ages of the HP-UHP rocks in the South Altyn Tagh, the North Qaidam and the North Qinling are 475–509, 420–457, and 485–514 Ma, respectively. The metamorphic ages of HP-UHP rocks in the North Qaidam are 20–80 Ma younger than those in the South Altyn Tagh and the North Qinling, and the metamorphic ages do not systematically increase or decrease from the South Altyn Tagh through the North Qaidam to the North Qinling. The absence of time transgressive variety of the metamorphism in the three regions does not support the hypothesis that the HP-UHP rocks in these regions form the same HP-UHP metamorphic zone. And the HP-UHP rocks in these regions can not be simply correlated to the collision between the North China plate and the South China plate. At present, the study of the HP-UHP rocks in the West and Middle Central China orogen faces several key issues or challenges, such as: (1) the continental subduction to the mantle depth of stishovite stability field (>9 GPa) is occasional or universal; (2) the mechanism of exhumation for the continental rocks subducted to the depth of stishovite stability field (>300 km); (3) the tectonic setting and geodynamical mechanism of producing the HP-UHP metamorphic zones in the South Altyn Tagh, the North Qaidam and the North Qinling. Further studies aiming at these problems will make important progress not only in metamorphism of the HP-UHP rocks in the West and Middle Central China orogen, but also in continental deep subduction and exhumation in solid earth science. It will also contribute to the establishment of the theory of continental deep subduction.

U–Pb zircon geochronology of coesite‐bearing eclogites from the southern Dulan area of the North Qaidam UHP terrane, northwestern China: spatially and temporally extensive UHP metamorphism during continental subduction

AbstractCoesite‐bearing eclogites from >100 km2in the southern Dulan area, North Qaidam Mountains (NQM) of western China, contain zircon that records protolith crystallization and ultra high pressure (UHP) metamorphism. Sensitive High‐Resolution Ion Microprobe (Mass Spectrometer) and Laser Ablation Inductively Coupled Plasma Mass Spectrometry U–Pb analyses from cathodoluminescence (CL)‐dark zircon cores in a coesite‐bearing eclogite yield an upper intercept age of 838 ± 50 Ma, and oscillatory zoned cores in a kyanite‐bearing eclogite gave a weighted mean206Pb/238U age of 832 ± 20 Ma. These zircon cores yield steep heavy rare earth element (HREE) slopes and negative Eu anomalies that suggest a magmatic origin. Thus,c. 835 Ma is interpreted as the eclogite protolith age. Unzoned CL‐grey or ‐bright zircon and zircon rims from four samples yield weighted mean ages of 430 ± 4, 438 ± 2, 446 ± 10 and 446 ± 3 Ma, flat HREE patterns without Eu anomalies, and contain inclusions of garnet, omphacite, rutile, phengite and rare coesite. These ages are interpreted to record 16 ± 5 Myr of UHP metamorphism. These new UHP ages overlap the age range of both eclogite and paragneiss from the northern Dulan area, suggesting that all UHP rock types in the Dulan area belong to the same tectonic unit. Our results are consistent with slow continental subduction, but do not match oceanic subduction and diapiric exhumation UHP model predictions. These new data suggest that, similar to eclogites in other HP/UHP units of the NQM and South Altyn Tagh, protoliths of the eclogites in the Dulan area formed in a continental setting during the Neoproterozoic, and then subducted to mantle depth together with continental materials during the Early Palaeozoic.

Petrology and geochronology of HP–UHP rocks from the South Altyn Tagh, northwestern China

Detailed field and petrological studies on the South Altyn Tagh in the last decade show that high-pressure (HP) to ultrahigh-pressure (UHP) metamorphic rocks are mainly exposed at Jianggalesayi and Qingshuiquan in the west, and at Yinggelisayi in the middle of the terrane. The South Altyn Tagh UHP rocks occur as lensoid blocks in granitic gneiss, paragneiss and marble and include eclogite, kyanite-garnet-bearing pelitic gneiss, magnesite-bearing garnet lherzolite, K-feldspar-bearing garnet clinopyroxenite and garnet-bearing granitic gneiss. Zircon U–Pb SHRIMP and LA-ICP-MS dating, combined with CL and trace element analysis yield geochronological data for different South Altyn Tagh HP/UHP rocks as follows: metamorphic ages of 493 ± 4 and 499 ± 27 Ma for the Jianggalesayi eclogite and its country rock respectively, 509 ± 12, 489 ± 8 and 487 ± 10 Ma for Yinggelisayi magnesite-bearing garnet lherzolite, K-feldspar-bearing garnet clinopyroxenite and garnet-bearing granitic gneiss, and 475 ± 4 and 486 ± 5 Ma for Qingshuiquan garnet clinopyroxenite and kyanite-bearing garnet-biotite gneiss. Magmatic protolith ages of eclogite, garnet lherzolite, garnet clinopyroxenite and garnet-bearing granitic gneiss are 754 ± 9, 844 ± 9, 821 ± 27 and 842 ± 18 Ma, respectively. Metamorphic ages of these rocks are consistent within errors, indicating that the South Altyn Tagh HP/UHP rocks were formed during 475–509 Ma; these are 20–80 Ma older than dated North Qaidam HP/UHP rocks (420–457 Ma). The occurrence of possible stishovite in pelitic gneiss and the older HP/UHP metamorphic ages suggest that the South Altyn Tagh belt may not necessarily be a western extension of the North Qaidam HP/UHP metamorphic belt, offset along the Altyn Tagh strike-slip fault.

A New Caledonian Khondalite Series in West Kunlun, China: Age Constraints and Tectonic Significance

The Kangxiwar ductile strike-slip shear zone marks the southern boundary of the West Kunlun terrane, a large, nearly E-W trending metamorphic terrane in the western Qinghai Tibet Plateau region. This ductile shear zone is ∼7 km wide, and consists of mylonitized khondalites. Protoliths of the khondalites were alumina-rich pelitic sedimentary and subordinate volcanic rocks. The pelitic khondalites have pronounced positive Th anomalies and subdued positive Ce and Zr anomalies, whereas the metavolcanic rocks have positive Nb and Zr anomalies. Both types of khondalite are LREE enriched, and show weak HREE depletions and moderate negative Eu anomalies. P-T conditions for the formation of the khondalites are estimated to be 6.8 kbar and 700°C. The khondalites formed in the Caledonian orogeny (428-445 Ma) and underwent strong shear deformation during the Indosinian (250-210 Ma). SHRIMP dating of detrital zircons in the khondalites suggests that they were derived from an older metamorphic basement, probably older than 644 Ma. The Kangxiwar khondalites are similar in their protoliths, trace- element and rare-earth element geochemistry, P-T conditions, and age of formation to those of the South Altyn Tagh khondalite series. This lateral correlation suggests that the West Kunlun and Altyn Tagh terranes were once contiguous, and provides evidence for the existence of a Caledonian orogenic belt in this region.

An Early Palaeozoic HP/HT granulite–garnet peridotite association in the south Altyn Tagh, NW China:P–Thistory and U‐Pb geochronology

AbstractHigh‐pressure kyanite‐bearing felsic granulites in the Bashiwake area of the south Altyn Tagh (SAT) subduction–collision complex enclose mafic granulites and garnet peridotite‐hosted sapphirine‐bearing metabasites. The predominant felsic granulites are garnet + quartz + ternary feldspar (now perthite) rocks containing kyanite, plagioclase, biotite, rutile, spinel, corundum, and minor zircon and apatite. The quartz‐bearing mafic granulites contain a peak pressure assemblage of garnet + clinopyroxene + ternary feldspar (now mesoperthite) + quartz + rutile. The sapphirine‐bearing metabasites occur as mafic layers in garnet peridotite. Petrographical data suggest a peak assemblage of garnet + clinopyroxene + kyanite + rutile. Early kyanite is inferred from a symplectite of sapphirine + corundum + plagioclase ± spinel, interpreted to have formed during decompression. Garnet peridotite contains an assemblage of garnet + olivine + orthopyroxene + clinopyroxene. Thermobarometry indicates that all rock types experienced peakP–Tconditions of 18.5–27.3 kbar and 870–1050 °C. A medium–high pressure granulite facies overprint (780–820 °C, 9.5–12 kbar) is defined by the formation of secondary clinopyroxene ± orthopyroxene + plagioclase at the expense of garnet and early clinopyroxene in the mafic granulites, as well as by growth of spinel and plagioclase at the expense of garnet and kyanite in the felsic granulite. SHRIMP II zircon U‐Pb geochronology yields ages of 493 ± 7 Ma (mean of 11) from the felsic granulite, 497 ± 11 Ma (mean of 11) from sapphirine‐bearing metabasite and 501 ± 16 Ma (mean of 10) from garnet peridotite. Rounded zircon morphology, cathodoluminescence (CL) sector zoning, and inclusions of peak metamorphic minerals indicate these ages reflect HP/HT metamorphism. Similar ages determined for eclogites from the western segment of the SAT suggest that the same continental subduction/collision event may be responsible for HP metamorphism in both areas.

Sapphirine-bearing high pressure mafic granulite and its implications in the south Altyn Tagh

Sapphirine-bearing high pressure mafic granulites are recognized in the Bashiwake area of the south Altyn Tagh. Mafic granulites and associated peridotites occur as lenses within kyanite-bearing high pressure felsic granulites. Sapphirine occurs as intergrowths with corundum, spinel and Ca-rich plagioclase in symplectite in between garnet and clinopyroxene. Reaction textures and mineral compositions indicate that sapphirine-bearing symplectites formed by reactions consuming kyanite, garnet and clinopyroxene. Therefore, both petrographic observations and the mineral compositions suggest that these quartz-free mafic granulites had an eclogite origin with an assemblage of garnet + clinopyroxene + kyanite, which is estimated to be stable atT = 1000 °C andP ⩾ 2.1 GPa. The sapphirine-bearing symplectites are resulted from isothermal decompression or decompression with slight cooling during exhumation of the host rock.

Sapphirine-bearing high pressure mafic granulite and its implications in the south Altyn Tagh

Sapphirine-bearing high pressure mafic granulite and its implications in the south Altyn Tagh

Present‐Time Crustal Deformation in China and its Surrounding Regions by GPS

AbstractApplying recent 10‐year GPS measurement data from some nationwide GPS networks, several regional GPS monitoring networks and the Asia‐Pacific Regional Geodetic Project (APRGP), this paper gives out a combined, consistent and unified velocity field solution in ITRF97 by rotation transformation of regional GPS network results. In order to study the characteristics of present‐time intra‐plate crustal deformation of China, we have constructed a new present‐time plate motion model named ITRF97VEL. The model can better describe present‐time features of global plate motion than the geological model NNR‐NUVEL1A. Based on the present time plate motion model ITRF97VEL, deformation velocities of more than 260 GPS sites are determined. The results show the crustal motion in China is especially inhomogeneous. The crustal deformation in the west of China is far stronger and more complicated than that in the east of China taking the N‐S seismic belt of China as a boundary. The deformation velocity gradually reduces from south to north in the west of China by energy release in several W‐E direction arc suture zones. The Qinghai‐Xizang Plateau is shortening in north‐south direction and extending in west‐east direction due to the strong shove of Indian plate.The shortening of about 15mm/a and 9–13mm/a is accommodated across Hymalayan block and the west Tian Shan respectively. Within southern Tibet,between the longitudes of 80°E to 91°E,there is E‐W extension of 20.2±1:2 mm/a. The slip rates of KJFZ in south Tibet and Altyn Tagh fault are 2–3mm/a and 4–6 mm/a respectively. Our GPS results indicate there is a less than 7mm/a shortening within the Longmen Shan. These results support the supposition of crustal thickening.