Late Ordovician Reefs and the Biological Crisis at the Ordovician–Silurian Boundary

Reef formation in the Late Ordovician was relatively widespread in the Sandbian and Katian times. In the late Katian, it gradually reduced and ended in the Hirnantian, before the end of the Ordovician. In parallel, reef-building skeleton frame-building biota disappeared and was replaced with algae and calcimicrobes.     

Geochemistry and petrogenesis of the Late Mesozoic–Early Cenozoic volcanic rocks of the Okhotsk and Japan marginal seas

The results of ICP-MS trace-element (LILE, HFSE, REE) study of the Late Mesozoic–Early Cenozoic volcanic rocks of the Okhotsk and Japan seas and geochronological K-Ar dating of the Eocene volcanic rocks are presented. Specifics of volcanism developed on submarine rises of these seas was characterized for the first time, and magma sources and geodynamic settings of the volcanic complexes predating the formation of the deep-water basins were determined. It is established that the Late Mesozoic magmas were formed in a subduction setting from spinel peridotites of suprasubduction mantle wedge, which was metasomatically reworked by aqueous fluids that were released by dehydration of sedimentary layer of subducting oceanic plate. This follows from the elevated concentrations of H₂O, alkalis, potassium, LILE and LREE, and lowered HFSE (including Ta-Nb minimum) and HREE contents, at lowered Sm/Yb, Nb/Ta, Nb/Y and elevated La/Nb, Ba/La, and Zr/Y ratios. Eocene adakite-like volcanic rocks were identified for the first time in the Sea of Okhotsk. They vary from andesitic to more felsic compositions with elevated MgO (>4%) and elevated La/Yb (>14) and Sr/Y (50–60) ratios. Identification of adakite-like volcanic rocks serves as evidence in support of the transform continental-margin (or plate sliding) setting, which is characterized by breaking apart of subduction slab and formation of slab “windows” acting as pathways for the transfer of asthenospheric mantle into continental lithosphere. New geochemical data on the Late Mesozoic–Early Cenozoic volcanic rocks of the Okhotsk and Japan seas and analysis of literature data were used to distinguish two geodynamic settings within these seas: subduction and transform margin. Similar settings operated at that time in the adjacent continental- margin volcanic belts (Akinin and Miller, 2011; Martynov and Khanchuk, 2013; et al.).     

Structure and Evolution of the Belomorian–Severodvinsk Shear Zone in the Late Proterozoic and Phanerozoic,East European Platform

Geotectonics - The tectonics, morphological features, and development stages of the Belomorian‒Severodvinsk shear zone (northwestern part) found in the East European Platform are considered....     

Origin and geodynamic evolution of Late Paleogene magmatic associations along the Periadriatic–Sava–Vardar magmatic belt

Along the Periadriatic Lineament in the Alps and the Sava–Vardar Zone of the Dinarides and Hellenides, Paleogene magmatic associations form a continuous belt, about 1700 km long. The following magmatic associations occur: (1) Eocene granitoids; (2) Oligocene granitoids including tonalites; (3) Oligocene shoshonite and calc-alkaline volcanics with lamprophyres; (4) Egerian–Eggenburgian (Chattian) calc-alkaline volcanics and granitoids. All of these magmatic associations are constrained by radiometric ages, which indicate that the magmatic activity was mainly restricted to the time span between 55 and 29 Ma. These igneous rocks form, both at surface and in the subsurface, the distinct linear Periadriatic–Sava–Vardar magmatic belt, with three strikes that are controlled by the indentation of Apulia and Moesia and accompanying strike-slip faulting. The geology, seismicity, seismic tomography and magnetic anomalies within this belt suggest that it has been generated in the African–Eurasian suture zone. Based on published analytical data, the petrology, major and trace element contents and Sr, Nd and O isotopic composition of each magmatic association are briefly defined. These data show that Eocene and Oligocene magmatic associations of the Late Paleogene Periadriatic–Sava–Vardar magmatic belt originated along a consuming plate margin. Based on isotopic systems, two main rock groups can be distinguished: (1) ⁸⁷Sr/⁸⁶Sr = 0.7036–0.7080 and δ¹⁸O = 5.9–7.2‰, indicating basaltic partial melts derived from a continental mantle–lithosphere, and (2) ⁸⁷Sr/⁸⁶Sr = 0.7090–72131 and δ¹⁸O = 7.3–11.5‰, indicating crustal assimilation and melting. The mantle sources for the primary basalt melts are metasomatized garnet peridotites and/or spinel lherzolites and phlogopite lherzolites of upper mantle wedge origin. The geodynamic evolution of the plutonic and volcanic associations of the Periadriatic–Sava–Vardar magmatic belt was related to the Africa–Eurasia suture zone that was dominated by break-off of the subducted lithospheric slab of Mesozoic oceanic crust, at depths of 90–100 km. This is indicated by their contemporaneity along the 1700 km long belt.     

Late Pleistocene lake and glaciation evolution on the northeastern Qinghai–Tibetan Plateau: a review

Late Pleistocene paleoclimatic history on northeastern Qinghai–Tibetan Plateau (QTP) has been reconstructed mainly from lake sediments; however, data regarding dry–wet climate changes reported in this region are still not clear and controversial. Based on shoreline features and highstand lacustrine sediments around lakes on the QTP, high lake level histories in this paper were summarized and compared with paleoclimatic records from lake sediments, ice core and glaciation evolution surrounding mountains on the NE QTP during late Pleistocene. The results indicate that periods of high lake level occurred at MIS 5, MIS 3 and early-middle Holocene and most likely corresponding to warm and wet climate periods, while periods of low lake level existed in intervening intervals, corresponding to cold and dry climate periods, which most likely coincide with glacial advances surrounding high mountains. With an exception, no wide glacial advance in study area was found during MIS 3, possibly suggesting that effective moisture is lower than that in the other region of NE QTP in this period.     

Molecular and structural-group characteristics of hydrocarbons in Late Devonian oils of the Timan–Pechora Province

The paper presents gaz chromatography–mass spectrometry and ¹H- and ¹³C-NMR data on the composition of hydrocarbon markers and structural-group composition of oils in the Timan–Pechora oil and gas province. The set of samples is subdivided into groups whose oils differ in composition and the distribution of their polycyclic biomarkers. All of the oils show closely similar geochemical characteristics, types of their source organic matter, and thermal maturity. Comparison of oil characteristics (composition of the polycyclic biomarkers) and parameters determined by chromatography–mass spectrometry makes it possible to reveal certain important (and calling for further investigation) relations between the composition of the structural groups of hydrocarbons in the oil fluid and its geochemical characteristics.     

Late Neogene tectonics in northwestern Victoria: Evidence from the Late Miocene–Pliocene Loxton Sand

The Late Miocene–Pliocene Loxton Sand strandplain extends across the western part of the Murray Basin in southeastern Australia. Gamma logging on groundwater bores surrounding Lake Tutchewop, which lies close to the eastern limit of this strandplain, showed that a heavy mineral layer within the Loxton Sand is displaced across the northern extension of the Leaghur Fault. A crevasse splay sand within the overlying Pliocene Shepparton Formation is also displaced, indicating that tectonic activity along the Leaghur Fault occurred in the Early Pliocene. This coincides with the Kosciusko Uplift, a major phase of Neogene tectonism across southeastern Australia, which also resulted in movement along the Danyo, Hindmarsh, Tyrell and Avoca Faults in northwestern Victoria.     

Tectono–sedimentary Evolution of the Late Triassic Xujiahe Formation in the Sichuan Basin

The early stage of Sichuan Basin formation was controlled by the convergence of three major Chinese continental blocks during the Indosinian orogeny that include South China,North China,and Qiangtang blocks.Although the Late Triassic Xujiahe Formation is assumed to represent the commencement of continental deposition in the Sichuan Basin,little research is available on the details of this particular stratum.Sequence stratigraphic analysis reveals that the Xujiahe Formation comprises four third-order depositional sequences.Moreover,two tectono-sedimentary evolution stages,deposition and denudation,have been identified.Typical wedge-shaped geometry revealed in a cross section of the southern Sichuan Basin normal to the Longmen Shan fold-thrust belt is displayed for the entire Xujiahe Formation.The depositional extent did not cover the Luzhou paleohigh during the LST1 to LST2 （LST,TST and HST mean Iowstand,transgressive and highstand systems tracts,1,2,3 and 4 represent depositional sequence 1,2,3 and 4）,deltaic and fluvial systems fed sediments from the Longmen Shan belt,Luzhou paleohigh,Hannan dome,and Daba Shan paleohigh into a foreland basin with a centrally located lake.The forebulge of the western Sichuan foreland basin was located southeast of the Luzhou paleohigh after LST2.According to the principle of nonmarine sequence stratigraphy and the lithology of the Xujiahe Formation,four thrusting events in the Longmen Shan fold-thrust belt were distinguished,corresponding to the basal boundaries of sequences 1,2,3,and 4.The northern Sichuan Basin was tilted after the deposition of sequence 3,inducing intensive erosion of sequences 3 and 4,and formation of wedge-shaped deposition geometry in sequence 4 from south to north.The tilting probably resulted from small-scale subduction and exhumation of the western South China block during the South and North China block collision.     

Late Cretaceous–Cenozoic uplift,deformation, and erosion of the SW Tianshan Mountains in Kyrgyzstan and Western China

The Mesozoic to Cenozoic mountain uplift, exhumation, and deformation of the SW Tianshan Mountains (Kyrgyzstan and Northwest China) offer an important window to understand the intra-continental rejuvenation mechanism of the Central Asian Orogenic Belt (CAOB), as response to the far-field effects of the India-Asia collision. This article presents new observation and data for the planation surface and sedimentation and deformation features of the regional intermountain basins to rebuild the orogenic history in Mesozoic to Cenozoic. Three planation surfaces were recognized by field observation, showing that the mountain may have experienced lengthy erosion since the end Cretaceous, and a continuous planation surface may have formed at the Eocene to Oligocene. The filling sequences and deformation character revealed that the orogenic disintegrate and intermountain basin formation likely began in the end of Oligocene. Subsequently, the uniform planation surface in Western Tianshan may have begun to disintegrate, leading to the basin-and-range landform formation. Folds and nappes in the Cenozoic basins, large-scale thrusting of Palaeozoic rocks over Cenozoic sediments at the basin margin associated with the rapid mountain uplift may have occurred at the end of Early Pleistocene, suggesting a tectonic inversion. The Mesozoic–Cenozoic Tianshan uplift and deformation were likely induced by the collision/accretion along the southern margin of Eurasia. Both the northward propagation of the Parmir syntaxis to the SW Tianshan and the oblique dextral faulting of the Talas–Fergana fault have likely played an important role on the formation and deformation of the Cenozoic basins in the SW Tianshan.     

The paleogeographic and stratigraphic confinement of giant floods in West Siberia in the Late Neopleistocene–Holocene

The concepts of the role of catastrophic breakthroughs of ice- and rock-dammed and thermokarst lakes in West Siberia in the Late Neopleistocene–Holocene are systematized. The Late Neopleistocene glacial maximum in the mountains and on the plain was obviously at the same time, at 90–60 ka. It has been revealed that the basal part of the Late Quaternary cyclic three-stage upper Ob' River terrace is formed by catafluvial sediments including boulder-gravels, which descend from the valley edge beneath the water line. The Early Karginian (Kharsoimian) marine layers are spatially related to the valleys of the rushed waters of ice-dammed Lake Ermakovskoe. Substantiation is given to the concept of catastrophic flows that arrived at the plain from the Pamir and Tien Shan mountains in the Holocene Optimum and carried the Aral microfauna through the Turgai trough into the Lake Chany area. Floods resulted from the breakthrough of thermokarst lakes in the north of the West Siberian plain were typical in Karginian and Holocene time. The breakthroughs of moraine-dammed basins in the Altai Mountains took place mainly in Karginian time, whereas the breakthroughs of rock-dammed lakes, in the Sartan and Holocene epochs.     

Structure and tectonic evolution of the Late Jurassic–Early Cretaceous Wandashan accretionary complex,NE China

The Late Jurassic–Early Cretaceous Wandashan accretionary complex (AC) in NE China is a key region for constraining the subduction and accretion of the Palaeo-Pacific Ocean; however, the protoliths and structure of the region remain poorly understood, resulting in debates regarding crustal growth mechanisms and subduction-related accretionary processes in Northeast China. In this contribution, we integrate detailed field observations, ocean plate stratigraphy (OPS) reconstruction, and associated geological data to determine the structure and tectonic evolution of the Wandashan AC. The Wandashan AC formed through the progressive incorporation of OPS units along an oceanic trench. The observed OPS comprises, in ascending order, Permian basalt and limestone, Middle Triassic–Early Jurassic chert, Middle Jurassic siliceous shale and mudstone, and Late Jurassic–Early Cretaceous turbidite. Numerous NNE–SSW-striking thrust faults have segmented the OPS into a series of bedding-parallel tectonic slices that were successively thrust over the Jiamusi massif along a basal thrust (the Yuejinshan Fault), producing a large-scale imbricate thrust system. The Wandashan AC underwent oceanward accretion via multiple deformational processes. The OPS units were detached and rearranged along or within a decollement through offscraping, underplating, thrusting, and duplexing. The units were then emplaced over the Jiamusi massif along the basal thrust. The timing of accretion and thrusting is constrained to the latest Middle Jurassic to earliest Early Cretaceous (ca. 167–131 Ma). Reconstructed accretion-related structural lines within the Wandashan AC trend dominantly NE–SW, close to the direction of Jurassic extension at the eastern Asian continental margin. Large-scale left-lateral strike-slip movement on the Dunmi Fault during the late Early Cretaceous resulted in the folding of structural lines within the Wandashan AC, producing their present-day westward-convex orientation.     

Constraints on the paleogeographic evolution of the North China Craton during the Late Triassic–Jurassic

This paper reports U–Pb–Hf isotopes of detrital zircons from Late Triassic–Jurassic sediments in the Ordos, Ningwu, and Jiyuan basins in the western-central North China Craton (NCC), with the aim of constraining the paleogeographic evolution of the NCC during the Late Triassic–Jurassic. The early Late Triassic samples have three groups of detrital zircons (238–363 Ma, 1.5–2.1 Ga, and 2.2–2.6 Ga), while the latest Late Triassic and Jurassic samples contain four groups of detrital zircons (154–397 Ma, 414–511 Ma, 1.6–2.0 Ga, and 2.2–2.6 Ga). The Precambrian zircons in the Late Triassic–Jurassic samples were sourced from the basement rocks and pre-Late Triassic sediments in the NCC. But the initial source for the 238–363 Ma zircons in the early Late Triassic samples is the Yinshan–Yanshan Orogenic Belt (YYOB), consistent with their negative zircon ε_Hf(t) values (−24 to −2). For the latest Late Triassic and Jurassic samples, the initial source for the 414–511 Ma zircons with ε_Hf(t) values of −18 to +9 is the Northern Qinling Orogen (NQO), and that for the 154–397 Ma zircons with ε_Hf(t) values of −25 to +12 is the YYOB and the southeastern Central Asian Orogenic Belt (CAOB). In combination with previous data of late Paleozoic–Early Triassic sediments in the western-central NCC and Permian–Jurassic sediments in the eastern NCC, this study reveals two shifts in detrital source from the late Paleozoic to Jurassic. In the Late Permian–Early Triassic, the western-central NCC received detritus from the YYOB, southeastern CAOB and NQO. However, in the early Late Triassic, detritus from the CAOB and NQO were sparse in basins located in the western-central NCC, especially in the Yan’an area of the Ordos Basin. We interpret such a shift of detrital source as result of the uplift of the eastern NCC in the Late Triassic. In the latest Late Triassic–Jurassic, the southeastern CAOB and the NQO restarted to be source regions for basins in the western-central NCC, as well as for basins in the eastern NCC. The second shift in detrital source suggests elevation of the orogens surrounding the NCC and subsidence of the eastern NCC in the Jurassic, arguing against the presence of a paleo-plateau in the eastern NCC at that time. It would be subsidence rather than elevation of the eastern NCC in the Jurassic, due to roll-back of the subducted paleo-Pacific plate and consequent upwelling of asthenospheric mantle.     

Middle–Late Paleozoic Duplex Rifting of the Barents Continental Margin and the Role Played in Formation of the East Barents Megabasin

Based on analysis and interpretation of seismic and other geological-geophysical data, duplex rifting is identified in the Paleozoic evolution of the South Barents Basin. Its first, pre–Late Devonian, phase was manifested on the southeastern side zone that limited the Pechora Plate structures. After a certain pause, a second, pre–Late Carboniferous phase involved the western Barents Sea region, including the slope of the Central Barents Rise and the western South Barents Basin. Thus, Late Paleozoic riftogenic structures in the western and southeastern South Barents Basin formed at different times. All this caused an asymmetric structure profile and asynchronicity of evolution of the rift system sides. In the Mesozoic, under the effect of formation of the Novaya Zemlya fold-and-thrust structure, the asymmetry of the riftogenic trough became even more contrasting.     

Late Glacial and Holocene avulsions of the Rio Pastaza Megafan (Ecuador–Peru): frequency and controlling factors

The geomorphological study by means of remote sensing imagery of the Rio Pastaza Megafan (Ecuador and northern Peru) reveals the traces of numerous avulsions. One hundred and eight avulsion sites have been defined. The location of these sites, the available radiocarbon ages as well as historical maps of the seventeenth century, enable us to propose an evolution history of the migration and avulsions of the Rio Pastaza since the Last Glacial Maximum. The first avulsions of the Río Pastaza occurred after the LGM in a zone close to and roughly parallel to the sudandean front, where the developed avulsion gave a distributive pattern to the ancient stream of the Río Pastaza in an area located between the modern Río Morona and Pastaza, where they caused the Rio Pastaza to develop a fan-like distributary pattern. This is interpreted as a response to thrust-related forelimb tilt, progressively shifting eastward the Rio Pastaza and the apex of the megafan. This sequence of events ended with the Great Diversion of the Rio Pastaza towards the modern Rios Corrientes and Tigre. Avulsions occurred in the Tigre-Corrientes Area between 9200 and 8,500 years Cal BP. Afterwards, the Río Pastaza was diverted to its present-day north–south course. This last significant avulsion occurred before AD 1691. In the area located between the modern Río Morona and Pastaza, avulsion frequency—probably overestimated—ranges between 100 and 200 years. In the Ríos Tigre and Corrientes area, avulsion frequency—probably underestimated—ranges from 300 to 400 years. Regional tectonics is likely to have triggered most of the avulsions in the Morona Pastaza area but its influence is restricted to this area. The factors controlling the avulsions in the Tigre-Corrientes area are less clear because the frequently described “hydrologic”-driven avulsion as observed in areas characterized by contrasted hydrologic cycles are inconsistent with the characteristics of the hydrologic cycles of the Rio Pastaza.     

Late Permian and Early Triassic magmatic pulses in the Angara–Taseeva syncline,Southern Siberian Traps and their possible influence on the environment

Recently it has been suggested that the major influence on the environment from Siberian Traps magmatism was due to the interaction of magma and organic-rich shale and petroleum-bearing evaporites, with the subsequent creation and outburst of toxic gases (Siberian gas venting: SGV model). In part this idea was supported by a U-Pb age of 252.0 ± 0.4 Ma for one of the dolerite sills in the southeastern Siberian Traps: the age corresponds to the Permo-Triassic boundary and its known mass extinctions of biota. In this study two other dolerite sills were dated using zircons by the U-Pb SHRIMP method at 254.2 ± 2.3 Ma and 249.6 ± 1.5 Ma. The former age is in agreement within error with the age previously published for the dolerite sills, whereas the latter age is in agreement with U-Pb ages published for lava and intrusions from the northern Siberian Traps. The new ages corresponds to the Cahngshingian/Wuchiapingian or Permian/Triassic and Spathian/Smithian boundaries, respectively. Review of ⁴⁰Ar/³⁹Ar and U-Pb SHRIMP ages previously published for the southeastern Siberian Traps shows that three other pulses of magmatism probably took place at respectively Anisian/Spathian, Late/Middle Anisian and Landian/Anisian boundaries. Thus it is possible that the SVG model can be applied also to lesser biotic extinctions and recoveries in proximity and aftermath to the main Permo-Triassic extinction.     

Late Miocene–Quaternary rapid stepwise uplift of the NE Tibetan Plateau and its effects on climatic and environmental changes

The way in which the NE Tibetan Plateau uplifted and its impact on climatic change are crucial to understanding the evolution of the Tibetan Plateau and the development of the present geomorphology and climate of Central and East Asia. This paper is not a comprehensive review of current thinking but instead synthesises our past decades of work together with a number of new findings. The dating of Late Cenozoic basin sediments and the tectonic geomorphology of the NE Tibetan Plateau demonstrates that the rapid persistent rise of this plateau began ~ 8 ± 1 Ma followed by stepwise accelerated rise at ~ 3.6 Ma, 2.6 Ma, 1.8–1.7 Ma, 1.2–0.6 Ma and 0.15 Ma. The Yellow River basin developed at ~ 1.7 Ma and evolved to its present pattern through stepwise backward-expansion toward its source area in response to the stepwise uplift of the plateau. High-resolution multi-climatic proxy records from the basins and terrace sediments indicate a persistent stepwise accelerated enhancement of the East Asian winter monsoon and drying of the Asian interior coupled with the episodic tectonic uplift since ~ 8 Ma and later also with the global cooling since ~ 3.2 Ma, suggesting a major role for tectonic forcing of the cooling.     

Lithology,Biostratigraphy, and Geochronology of the Late Pleistocene–Holocene Sediments on the Coast of Onega Bay of the White Sea

Doklady Earth Sciences - This paper reports on the lithological, micropaleontological, and chronometric data (radiocarbon dating) for one of the areas of the White Sea coast. The sedimentary...     

Petrogenesis of the Late Jurassic peraluminous biotite granites and muscovite-bearing granites in SE China: geochronological,elemental and Sr–Nd–O–Hf isotopic constraints

Biotite granites and muscovite-bearing granites are dominant rock types of the widespread granites in SE China. However, their petrogenesis has been enigmatic. A combined study of zircon U–Pb dating and Lu–Hf isotopes, whole-rock element geochemistry and Sr–Nd–O isotopes was performed for three late Mesozoic granitic plutons (Xinfengjie, Jiangbei and Dabu) in central Jiangxi province, SE China. All the plutons are composed of biotite granites and muscovite-bearing granites that have been poorly investigated previously. The new data not only allow us to assess their sources and magma evolution processes, but also helps us to better understand the genetic link to the large-scale polymetallic mineralization in SE China. LA-ICP-MS zircon U–Pb dating shows that three plutons were emplaced in the Late Jurassic (159–148 Ma) and that the muscovite-bearing granites are almost contemporaneous with the biotite granites. The biotite granites have SiO₂ contents of 70.3–74.4 wt% and are weakly to strongly peraluminous with ASI from 1.00 to 1.26, and show a general decrease in ASI with increasing SiO₂. They have relatively high zircon saturation temperatures (T _Zr = 707–817 °C, most > 745 °C) and show a general decrease in T _Zr with increasing SiO₂. They have high initial ⁸⁷Sr/⁸⁶Sr ratios (0.7136 to 0.7166) and high δ¹⁸O values (9.1–12.8‰, most > 9.5‰) and clearly negative ε _Nd (T) (? 9.5 to ? 11.8) and ε _Hf (T) (in situ zircon) (? 13.1 to ? 13.5). The muscovite-bearing granites have high SiO₂ contents (74.7–78.2 wt%). They are also weakly to strongly peraluminous with ASI of 1.04–1.18 but show a general increase in ASI with increasing SiO₂. They have relatively low T _Zr (671–764 °C, most < 745 °C) and also show a general decrease in T _Zr with increasing SiO₂. The muscovite-bearing granites have high Rb (up to 810 ppm) and high (K₂O + Na₂O)/CaO (up to 270), Rb/Sr (up to 42) and Rb/Ba (up to 30) as well as low K/Rb (< 150, down to 50), Zr/Hf (< 24, down to 11) and Nb/Ta (< 6, down to 2). They show similar Nd–O–Hf isotopic compositions to the biotite granites with ε _Nd (T) of ? 8.7 to ? 12.0, δ¹⁸O of 8.7–13.0‰ (most > 9.5‰) and ε _Hf (T) (in situ zircon) of ? 11.3 to ? 13.1. Geochemical data suggest the origin of the biotite granites and muscovite-bearing granites as follows: Partial melting of Precambrian metasedimentary rocks (mainly two-mica schist) in the lower crust at temperatures of ca. 820 °C generated the melts of the less felsic biotite granites. Such primary crustal melts underwent biotite-dominant fractionation crystallization, forming the felsic biotite granites. Progressive plagioclase-dominant fractionation crystallization from the evolved biotite granites produced the more felsic muscovite-bearing granites. Thus, the biotite granites belong to the S-type whereas the muscovite-bearing granites are highly fractionated S-type granites. We further suggest that during the formation of the muscovite-bearing granites the fractional crystallization was accompanied by fluid fractionation and most likely the addition of internally derived mineralizing fluids. That is why the large-scale polymetallic mineralization is closely related to the muscovite-bearing granites rather than biotite granites in SE China. This is important to further understand the source and origin of biotite granites and muscovite-bearing granites in SE China even worldwide.