Central Asia is an ideal laboratory to study geodynamics and continental growth in the Phanerozoic (Şengör et al. 1993; Şengör and Natal’in 1996; Jahn et al. 2004; Xiao et al. 2004a, b; Kröner et al. 2007; Windley et al. 2007; Jian et al. 2008). Three important orogenic collages are exposed in Central Asia, i.e. the Altaids or Central Asian Orogenic Belt in the north, Tethysides in the south, and Western Pacific orogenic collages in the east. The architecture of Central Asia was mainly constructed from the interactions between these collages (Isozaki et al. 1990; Şengör et al. 1993; Yin and Nie 1996; Maruyama 1997; Xiao et al. 2008a, b).

The interaction among these collages was the major topic of a 5-day thematic workshop on “Geodynamic Evolution of Central Asia in the Paleozoic and Mesozoic”, held in Beijing, China, in December 2006 and funded by the Sino-German Centre for Research Promotion (Chinesisch-Deutsches Zentrum für Wissenschaftsförderung) (Xiao and Kröner 2007). The workshop was attended by more than 50 participants representing eight countries (Germany, UK, France, Russia, Australia, Italy, Cuba, and China) and was co-sponsored jointly by Task Force I (Earth Accretionary Systems) of the International Lithosphere Program (ILP), IGCP Project 480, and the State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences (CAS).

The current thematic volume arises from this workshop and also includes several invited contributions. The 18 papers in this volume reflect a relatively broad spectrum of current research and cover regions in the southern Altaids as well as the northern Tethysides and the Japan Islands where the Altaids and Tethysides possibly join (Fig. 1).

Fig. 1
figure 1

Schematic tectonic map of Central Asia showing the Altaids and other orogenic collages with contributions in this volume marked as boxes or crosses (adapted from de Jong et al. 2006; Xiao et al. 2003, 2004a, 2008a). EUC East European Craton

Full size image

Wenjiao Xiao and co-authors (this volume) synthesize accretionary processes during final terrane amalgamation in the Altai and Tien Shan Mountain Range of NW China and Inner Mongolia in the late Permian to mid-Triassic. They use structural, geochemical, geochronological and palaeomagnetic data to show that there was continuous southward accretion in the late Paleozoic to middle Triassic of volcanic arcs, accretionary wedges and HP- to UHP-metamorphic rocks. Final closure of the Paleoasian Ocean led to docking of the Tarim and North China Cratons with the amalgamated CAOB terrranes and terminal orogenesis. This complex geodynamic evolution led to formation of major metal deposits and substantial crustal growth.

Jun Gao and co-authors (this volume) provide geochemical data and zircon ages for metaluminous to weakly peraluminous granitoids in the southern Chinese Tianshan and relate these to continental arc settings between ca. 480 and 275 Ma ago. These authors favor Silurian to Carboniferous northward subduction of the South Tianshan oceanic plate beneath the southern margin of the Central Tianshan-Kazakhstan-Yili continental plate and argue for completion of terrane accretion and collision in the Permian.

Koen de Jong and co-authors (this volume) present laser-probe dating of mylonite whole-rock samples from the North Tianshan—Main Tianshan fault zone, represented by 40Ar/39Ar spectra with ages of 255–285 Ma. The Permian ages of mylonites date movement on these ductile, dextral strike-slip shear zones, whereas the mica ages are interpreted to reflect recrystallisation as a result of fluid flow around such transcurrent faults.

Wei Lin and co-authors (this volume) present a new model for the polyphase structural evolution of the southwestern Chinese Tianshan, including a high-pressure blueschist-eclogite belt. They propose that Devonian to Carboniferous north-directed thrusting resulted from south-directed subduction, and was followed by Permian dextral wrenching.

Bo Wang and co-authors (this volume) use LA-ICPMS and Ar–Ar data to reveal a coincidence in time between regional wrench faulting and granitoid emplacement in the western Chinese Tianshan. They argue for coexistence of diverse magmatic sources during the same tectonic episode and suggest that post-collisional lithosphere-scale transcurrent shear zones tightly controlled the magmatic activity during the transition from convergent margin to intraplate anorogenic processes.

Wen Su and co-authors (this volume) examined chemically-zoned amphibole porphyroblasts from a high-pressure eclogite of the western Chinese Tianshan, using an electron microprobe, micro Fourier-transaform infrared and micro-Raman spectroscopy. The data show glaucophane end-member compositions in the cores and intermediate amphibole compositions in the rims.

Tiannan Yang and co-authors (this volume) undertook structural and microtectonic analyses and Ar/Ar geochronology on rocks from the Turfan basin in NW China to demonstrate that NS-directed contractional deformation operated at ca. 266 Ma along the southern boundary of the unified Junger-Turfan basin, and this gave rise to a NW-striking right-lateral transpressional ductile shear zone along the SW border of the Turfan basin and to an interference pattern and thrusts in the basin interior.

Zhenhua Zhao and co-authors (this volume) review middle Devonian magnesian andesites (MAs) that are common in the southern Altay, as well as Carboniferous MAs that occur in Alataoshan and West- and East-Tianshan in northern Xinjiang, NW China. They use new petrographic, chemical and isotopic data to suggest that the petrogenesis of the MAs in the northern Xinjiang region may have involved multiple sources, a combination of different petrogenetic processes, a high geothermal gradient, and unique tectonic settings including oblique subduction, slab break off, and subduction erosion.

Qingchen Wang and co-authors (this volume) studied the paleomagnetism and composition of detrital grains in Cretaceous and Tertiary sandstones in the Kezilenuer-Kuqa profile of the Chinese Tianshan and found that this part of the Tianshan underwent two phases of differential uplift, one in the early Cretaceous and the other from the late Cretaceous to Tertiary.

Antoine Demoux and co-authors (this volume) report SHRIMP zircon ages for granitoid gneisses from the Baga Bogd massif of southern Mongolia. They recognized several episodes of zircon growth, namely (1) gneiss protolith crystallization ages of 1,519 and 1,701 Ma, (2) granite-gneiss protolith emplacement ages between 954 and 983 Ma, the first record of early Neoproterozoic magmatic activity in the region, and (3) dioritic-granitic orthogneiss emplacement ages between 498 and 502 Ma, which the authors suggest represent granitoids emplaced along a southward-growing active continental margin of the CAOB.

Yannick Daoudene and coauthors (this volume) investigated a core complex and related Mesozoic rift basin in the Ereendavaa Range of NE Mongolia and determined that extension-related shearing was late Jurassic to early Cretaceous in age, coeval with similar extension-related core complexes in Transbaikalia and northern China, and probably related to a single, regionally extensive tectonic event.

Feng Guo and co-authors (this volume) examine a 135 Ma felsic volcanic suite of dacite and rhyolite from Huolinhe in NE China that is characterized by LILE- and light REE-enrichments, high field strength elements, Ti–P depletion, and high radiogenic Nd, Pb and Hf isotopes. Isotope calculations suggest that the magmas were derived from a mixture of juvenile crust (70–80%), and 20–30% of recycled crust with highly radiogenic Sr and Pb and unradiogenic Nd and Hf. The authors prefer a pre-Mesozoic crustal growth model related to arc accretion associated with Paleo-Asian ocean subduction.

Wei Liu and co-authors (this volume) use SHRIMP U-Pb dating, laser-ablation multi-collector ICPMS Hf isotopes and electron microprobe element analyses of inherited and magmatic zircons from five granitoid intrusions in the Linxi area, southern segment of the southern Altaids, to examine continental crustal growth processes. They conclude that continental growth in this region involved a three-step process, namely, subduction-accretion and repeated underplating, intermediate differentiation of juvenile rocks, and granitoid production from these differentiated rocks.

Shuan-Hong Zhang and co-authors (this volume) report geochemical data as well as zircon ages and Nd whole-rock isotopic systematics for early Permian calc-alkaline granitoids along the northern margin of the North China Craton (NCC). Previously regarded as Archean to Paleoproterozoic, they form part of a late Carboniferous to early Permian I-type plutonic suite, emplaced along an Andean-type active continental margin during southward subduction of the Paleo-Asian oceanic plate beneath the NCC. Their data and model imply that final collision of the Mongolian arc terranes with the NCC likely occurred in the late Permian to earliest Triassic.

Baochun Huang and co-authors (this volume) undertook a paleomagnetic study of Eocene-Pliocene formations in the Kashi Depression of SW Tarim and show that the depression behaved as a quasi-rigid block during rotation about a vertical axis of 20° counterclockwise relative to stable Eurasia during the late Neogene. They attribute the rotation to two-directional thrusting by North Pamir thrusts in the southwest and South Tianshan thrusts in the north.

Chao Yuan and co-authors (this volume) investigated a garnet-bearing tonalitic porphyry from the eastern Kunlun that has a SHRIMP zircon age of 213 Ma. Garnet mineralogy indicates a minimum pressure of 8–10 kbar. The rock is enriched in LILE and LREE and depleted in Nb and Ti, which are typical subduction-related features. Low MgO contents of garnet and ilmenite and oxygen isotope composition of garnets suggest derivation from a MASH zone of the lower crust. The authors suggest that early crystallization of apatite may have prevented some arc magmas from evolving into adakitic rocks under high water fugacity.

Jin Zhang and co-authors (this volume) studied the structural geology of the Aixa block situated on the northern side of the Qilian Shan. They report that the Altyn Tagh fault does not go through the Aixa block and that a regional conjugate fault system resulted from north-south compression of the Qinghai-Tibetan plateau to the south in the Miocene and Pliocene. The authors also discuss the formation of major sedimentary basins in the region in relation to the major conjugate fault systems.

Koen de Jong and co-authors (this volume) present 40Ar/39Ar laser-probe pseudo-plateau ages of 218.4 ± 0.4, 228.8 ± 0.9 and 231.9 ± 0.7 Ma that date high-P/T metamorphism of very low-grade, meta-pelitic, whole-rocks in the Sakaigawa unit. They suggest that this mid-late Triassic high-P/T metamorphic event took place in a subduction-accretion complex and was partly coeval with proto-Japan’s collision with proto-Eurasia along the southward extension of the Central Asian Orogenic Belt that gave rise to the main metamorphism in the Hida-Oki terrane.