http://www.sciencedirect.com/science/article/pii/S1674987114000668

Microbial diversity in the hydrate-containing (sites SH3B and SH7B) and-free (sites SH1B, SH5B, SH5C) sediments collected from the Shenhu area of the South China Sea (SCS) was investigated using 16S rR...     

http://www.sciencedirect.com/science/article/pii/S1674987112001260

Archaea have unique glycerol dialkyl glycerol tetraether (GDGT) lipids that can be used to develop paleotemperature proxies such as TEX₈₆. This research is to validate proposed GDGT-proxies for paleotemperature determination in the South China Sea (SCS). Samples were collected from core-top sediments (0–5 cm) in the northern SCS. Total lipids were extracted to obtain core GDGTs, which were identified and quantified using liquid chromatography-mass spectrometry (LC-MS). The abundance of isoprenoidal GDGTs (iGDGTs) ranged from 271.5 ng/g dry sediment to 1266.3 ng/g dry sediment, whereas the branched GDGTs (bGDGTs), supposedly derived from terrestrial sources, ranged from 22.2 ng/g dry sediment to 56.7 ng/g dry sediment. The TEX₈₆-derived sea surface temperatures ranged from 20.9 °C in the coast (water depth < 160 m) to 27.9 °C offshore (water depth > 1000 m). TEX₈₆-derived temperatures near shore (<160 m water depth) averaged 23.1 ± 2.5 °C (n = 4), which were close to the satellite-derived winter mean sea surface temperature (average 22.6 ± 1.0 °C, n = 4); whereas the TEX₈₆-derived temperatures offshore averaged 27.4 ± 0.3 °C (n = 7) and were consistent with the satellite mean annual sea surface temperature (average 26.8 ± 0.4 °C, n = 7). These results suggest that TEX₈₆ may record the sea surface mean annual temperature in the open ocean, while it likely records winter sea surface temperature in the shallower water.     

http://www.sciencedirect.com/science/article/pii/S1674987111001319

The microbial diversity in Wuli Area,Qinghai-Tibetan Plateau was investigated using 16S rRNA gene phylogenetic analyses.A total of 117 bacterial and 66 archaeal 16S rRNA gene clones were obtained from the Wuli cold springs.The bacterial clones could be classified into Pwteobacteria,Acidobacteria, Deinococci,Sphingobacteria,Flavobacteria.Nitrospirae,Actinobacteria,Gemmatimonadetes, and unclassified-bacteria;and the archaeal clones could be classified into Crenarchaeota and Thaumarchaeota.Among the major groups,Pwteobacteria and Crenarchaeota were dominant in the bacterial and archaeal 16S rRNA gene clone libraries,respectively.The clone sequences obtained in Wuli cold springs were closely related to those from cold habitats,such as snow/ice/soils on high mountains or at high latitude.Especially,the microbial community composition of Wuli Area was more similar to that in Tibetan glaciers than cold environments of other locations.The data presented in this study have implications for a better understanding of microbial diversity in cold springs on the Qinghai-Tibetan Plateau.     

http://www.sciencedirect.com/science/article/pii/S1674987112001284

This study deals with the biogeography of Antarctic microflora （Antarctica acts as best model to study microbial biogeography） such as cyanobacteria and selected halophiles with special emphasis on Halomonas variabilis and Bacillus licheniformis.Halophiles are known to be resistant not only to salt stress,but also to extreme temperature,pressure,and aridity and they are capable of surviving in harsh environments such as polar regions,deep-sea habitats,and deserts.Many microbes are known to be resistant to hostile environmental conditions,and are capable of surviving in harsh environments.Our group has isolated 444 strains belonging to 28 genera of halophiles from various environments around the world.The 16S rRNA gene sequences revealed that many of the isolated strains from geographically distant habitats having different environmental conditions,were closely related to each other,with some strains possessing 100％ identical sequences.Organisms possessing survival mechanism such as spore formation are usually ubiquitous.The genus Halomonas is represented by potentially endemic strains and the ubiquitous H.variabilis,while spore-forming B.licheniformis showed cosmopolitan distribution.One potentially endemic （moderate endemicity that is regional and/or continental distribution） strain was reported from Syowa station,East Antarctica,and Mario Zucchelli station,West Antarctica,which are geographically separated by 3000 km.Moreover,15 strains having 100％ similarity with B.licheniformis were considered cosmopolitans.The results of this work provide support for the middle-ground model that some microbes have moderate endemicity and others have cosmopolitan distribution.These results will contribute to a greater understanding of microbial biogeography with special emphasis on Antarctica.     

http://www.sciencedirect.com/science/article/pii/S1674987114001133

A chronological study of seamount rocks in the South China Sea basin provides a great opportunity to understand the expansion and evolution history of the sea basin. In this paper, we analyzed the 40Ar...     

http://www.sciencedirect.com/science/article/pii/S167498711200028X

Most Phanerozoic oolites are marked by ooids with a diameter less than 2 mm.Observations on a Neoproterozoic oolite have resulted in a change of concept.The term "pisolite" that traditionally referred to oolites with a grain size of more than 2 mm,is now restricted to those coated carbonate grains formed by meteoritic freshwater diagenesis;oolites with a grain size of more than 2 mm are now defined as "giant".Particular unusual giant oolites within a set of oolitic-bank limestones with thicknesses of more than 40 m in the top part of the Lower Triassic(Induan) Daye(Ruiping) Formation at the Lichuan section in the western part of Hubei Province in South China,represent an important sedimentological phenomenon in both the specific geological period and the geological setting that is related to the end-Permian biological mass extinction.Like the giant oolites of the Neoproterozoic that represent deposits where oolites formed in a vast low-angle carbonate ramp at that special geological period,the Triassic Daye Formation at the study section are significant because they provide a comparative example to help understand the evolving carbonate world reflected by oolites,the origin of which is still uncertain. and they give insight into the sedimentation pattern of the desolate sea floor,which resulted from the mass extinction at the turn of the Permian into the Tnassic.     

http://www.sciencedirect.com/science/article/pii/S1674987113000364

The South Tianshan Orogen and adjacent regions of Central Asia are located in the southwestern part of the Central Asian Orogenic Belt.The formation of South Tianshan Orogen was a diachronous,scissors-like process,which took place during the Palaeozoic,and its western segment was accepted as a site of the fnal collision between the Tarim Craton and the North Asian continent,which occurred in the late Palaeozoic.However,the post-collisional tectonic evolution of the South Tianshan Orogen and adjacent regions remains debatable.Based on previous studies and recent geochronogical data,we suggest that the fnal collision between the Tarim Craton and the North Asian continent occurred during the late Carboniferous.Therefore,the Permian was a period of intracontinental environment in the southern Tianshan and adjacent regions.We propose that an earlier,small-scale intraplate orogenic stage occurred in late Permian to Triassic time,which was the frst intraplate process in the South Tianshan Orogen and adjacent regions.The later largescale and well-known Neogene to Quaternary intraplate orogeny was induced by the collision between the India subcontinent and the Eurasian plate.The paper presents a new evolutionary model for the South Tianshan Orogen and adjacent regions,which includes seven stages:(I)late Ordovicianeearly Silurian opening of the South Tianshan Ocean;(II)middle Silurianemiddle Devonian subduction of the South Tianshan Ocean beneath an active margin of the North Asian continent;(III)late Devonianelate Carboniferous closure of the South Tianshan Ocean and collision between the Kazakhstan-Yili and Tarim continental blocks;(IV)early Permian post-collisional magmatism and rifting;(V)late PermianeTriassic the frst intraplate orogeny;(VI)JurassicePalaeogene tectonic stagnation and(VII)NeoceneeQuaternary intraplate orogeny.     

http://www.sciencedirect.com/science/article/pii/S1674987113000558

Several stratigraphic breaks and unconformities exist in the Mesoproterozoic successions in the northern margin of the North China Block.Geologic characters and spatial distributions of fve of these unconformities,which have resulted from different geological processes,have been studied.The unconformity beneath the Dahongyu Formation is interpreted as a breakup unconformity,representing the time of transition from continental rift to passive continental margin.The unconformities beneath the Gaoyuzhuang and the Yangzhuang formations are considered to be the consequence of regional eustatic fuctuations,leading to the exposure of highlands in passive margins during low sea-level stands and transgressive deposition on coastal regions during high sea-level stands.The unconformity atop the Tieling Formation might be caused by uplift due to contractional deformation in a back-arc setting,whereas the uplift after the deposition of the Xiamaling Formation might be attributed to a continental collision event.It is assumed that the occurrences of these unconformities in the Mesoproterozoic successions in the northern margin of the North China Block had a close bearing on the assemblage and breakup of the Columbia and Rodinia supercontinents.     

http://www.sciencedirect.com/science/article/pii/S1674987113000613

The effective elastic thickness （Te） represents the thickness of the elastic layer or the flexural rigidity of the lithosphere, the equivalent of which can be calculated from the spectral analysis of gravity and topographic data. Studies of Te have profound influence on intracontinental deformation, and coupling of the tectonic blocks. In this paper, we use the multitaper spectral estimation method to calculate the coherence between Bouguer gravity and topography data, and to obtain the Te map of South China. Through the process of correction, we discuss the relationships of Te versus heat flow, and Te versus seismicity. The results show that Te distribution of South China is affected by three factors：the original age, which controls the basic feature;the Mesozoic evolution, which affects the Te distribution;and the neotectonic movement, which shaped the final distribution. The crust age has a positive correlation with the first-order Te distribution;thus the Yangtze Craton has a relatively higher Te （about 50 km） whereas the Te in Cathaysia block is only 10e20 km. By analysis and comparison among the tectonic models of South China, the Te distribution can be well explained using the flat-subduction model. As is typical with neotectonics, the region with a higher heat flow is related with a lower Te. The seismicity does not have a clear relationship with Te, but the strong seismicity could cause a low Te. Seismogenic layer （Ts） has a similar trend as Te in the craton, whereas in other areas the relationship is complex.     

http://www.sciencedirect.com/science/article/pii/S1674987112001314

As one of the areas where typical late Archean crust is exposed in the Eastern Block of the North China Craton, the northern Laioning Complex consists principally of tonalitic-trondhjemitic-granodioritic (TTG) gneisses, massive granitoids and supracrustal rocks. The supracrustal rocks, named the Qingyuan Group, consist of interbedded amphibolite, hornblende granulite, biotite granulite and BIF. Petrological evidence indicates that the amphibolites experienced the early prograde (M1), peak (M2) and post-peak (M3) metamorphism. The early prograde assemblage (M1) is preserved as mineral inclusions, represented by actinotite + hornblende + plagioclase + epidote + quartz + sphene, within garnet porphyroblasts. The peak assemblage (M2) is indicated by garnet + clinopyroxene + hornblende + plagioclase + quartz + ilmenite, which occur as major mineral phases in the rock. The post-peak assemblage (M3) is characterized by the garnet + quartz symplectite. The P–T pseudosections in the NCFMASHTO system constructed by using THERMOCALC define the P–T conditions of M1, M2 and M3 at 490–550 °C/<4.5 kbar, 780–810 °C/7.65–8.40 kbar and 630–670 °C/8.15–9.40 kbar, respectively. As a result, an anticlockwise P–T path involving isobaric cooling is inferred for the metamorphic evolution of the amphibolites. Such a P–T path suggests that the late Archean metamorphism of the northern Liaoning Complex was related to the intrusion and underplating of mantle-derived magmas. The underplating of voluminous mantle-derived magmas leading to metamorphism with an anticlockwise P–T path involving isobaric cooling may have occurred in continental magmatic arc regions, above hot spots driven by mantle plumes, or in continental rift environments. A mantle plume model is favored because this model can reasonably interpret many other geological features of late Archean basement rocks from the northern Liaoning Complex in the Eastern Block of the North China Craton as well as their anticlockwise P–T paths involving isobaric cooling.     

http://www.sciencedirect.com/science/article/pii/S1674987111000235

In this paper we present a review of mineral systems in northern Xinjiang,NW China,focussing on the Tianshan,West and East Junggar and Altay orogenic belts,all of which are part of the greater Central Asian Orogenic Belt(CAOB).The CAOB is a complex collage of ancient microcontinents,island arcs,oceanic plateaux and oceanic plates,which were amalgamated and accreted in Early Palaeozoic to Early Permian times.The establishment of the CAOB collage was followed by strike-slip movements and affected by intrap...     

http://www.sciencedirect.com/science/article/pii/S1674987112000849

New methods are presented for processing and interpretation of shallow marine differential magnetic data,including constructing maps of offshore total magnetic anomalies with an extremely high resolution of up to 1-2 nT,mapping weak anomalies of 5-10 nT caused by mineralization effects at the contacts of hydrocarbons with host rocks,estimating depths to upper and lower boundaries of anomalous magnetic sources,and estimating thickness of magnetic layers and boundaries of tectonic blocks. Horizontal dimensions of tectonic blocks in the so-called "seismic gap" region in the central Kuril Arc vary from 10 to 100 km,with typical dimensions of 25-30 km.The area of the "seismic gap" is a zone of intense tectonic activity and recent volcanism.Deep sources causing magnetic anomalies in the area are similar to the "magnetic belt" near Hokkaido. In the southern and central parts of Barents Sea,tectonic blocks with widths of 30-100 km,and upper and lower boundaries of magnetic layers ranging from depths of 10 to 5 km and 18 to 30 km are calculated.Models of the magnetic layer underlying the Mezen Basin in an inland part of the White Sea-Barents Sea paleorift indicate depths to the lower boundary of the layer of 12-30 km.Weak local magnetic anomalies of 2-5 nT in the northern and central Caspian Sea were identified using the new methods,and drilling confirms that the anomalies are related to concentrations of hydrocarbon.Two layers causing magnetic anomalies are identified in the northern Caspian Sea from magnetic anomaly spectra.The upper layer lies immediately beneath the sea bottom and the lower layer occurs at depths between 30-40 m and 150-200 m.     

http://www.sciencedirect.com/science/article/pii/S1674987111001010

A large-scale pop-up structure occurs at the front of the northern Dabashan thrust belt (NDTB),bound by the NNE-dipping Chengkou fault to the south,and the SSW-dipping Gaoqiao fault to the north.The pop-up structure shows different features along its strike as a direct reflection of the intensity of tectonic activity.To the northwest,the structure is characterized by a two-directional thrust system forming a positive flower-like structure.In contrast,the southeastern part is composed of the vertical Chengkou fault and a series of N-directed backthrusts.showing a semi-flower-like structure. We present results from Ar-Ar dating of syntectonic microthermal nietamorphic sericite which show that the Chengkou fault experienced intense deformation during the mid-Mesozoic Yanshanian epoch(about 143.3 Ma),causing rapid uplift and thrusting of the northern Dabashan thrust belt.During the propagation of this thrust,a series of backthrusts formed because of the obstruction from the frontier of Dabashan thrust belt,leading to the development of the pop-up structure.     

http://www.sciencedirect.com/science/article/pii/S1674987110000095

<正>Bauxite deposits are studied because of their economic value and because they play an important role in the study of paleoclimate and paleogeography of continents.They provide a rare record of the weathering and evolution of continental surfaces.Geomicrobiological analysis makes it possible to verify that microorganisms have played a critical role during the formation of bauxite with the possibility already intimated in previous studies.Ambient temperature,abundance of water,organic carbon and bioavailable iron and other metal substrates provide a suitable environment for microbes to inhabit.Thio-bacillus, Leptospirilum,Thermophilic bacteria and Heterotrophs have been shown to be able to oxidize ferrous iron and to reduce sulfate-generating sulfuric acid,which can accelerate the weathering of alumi-nosilicates and precipitation of iron oxyhydroxides.Microorganisms referred to the genus Bacillus can mediate the release of alkaline metals.Although the dissimilatory iron-reducing and sulfate-reducing bacteria in bauxites have not yet been identified,some recorded authigenic carbonates and "bacteriopyrites" that appear to be unique in morphology and grain size might record microbial activity.Typical bauxite minerals such as gibbsite,kaolinite,covellite,galena,pyrite,zircon,calcium plagioclase,orthoclase, and albite have been investigated as part of an analysis of microbial mediation.The paleoecology of such bauxitic microorganisms inhabiting continental(sub) surfaces,revealed through geomicrobiolo-gical analysis,will add a further dimension to paleoclimatic and paleoenvironmental studies.     

http://www.sciencedirect.com/science/article/pii/S1674987112001041

Large igneous provinces (LIPs) are considered a relevant cause for mass extinctions of marine life throughout Earth’s history. Their flood basalts and associated intrusions can cause significant release of SO₄ and CO₂ and consequently, cause major environmental disruptions. Here, we reconstruct the long-term periodic pattern of LIP emplacement and its impact on ocean chemistry and biodiversity from δ³⁴S_sulfate of the last 520 Ma under particular consideration of the preservation limits of LIP records. A combination of cross-wavelet and other time-series analysis methods has been applied to quantify a potential chain of linkage between LIP emplacement periodicity, geochemical changes and the Phanerozoic marine genera record. We suggest a mantle plume cyclicity represented by LIP volumes (V) of V = ?(350–770) × 10³ km³ sin(2πt/170 Ma) + (300–650) × 10³ km³ sin(2πt/64.5 Ma + 2.3) for t = time in Ma. A shift from the 64.5 Ma to a weaker ～28–35 Ma LIP cyclicity during the Jurassic contributes together with probably independent changes in the marine sulfur cycle to less ocean anoxia, and a general stabilization of ocean chemistry and increasing marine biodiversity throughout the last ～135 Ma. The LIP cycle pattern is coherent with marine biodiversity fluctuations corresponding to a reduction of marine biodiversity of ～120 genera/Ma at ～600 × 10³ km³ LIP eruption volume. The 62–65 Ma LIP cycle pattern as well as excursion in δ³⁴S_sulfate and marine genera reduction suggest a not-yet identified found LIP event at ～440–450 Ma.     

http://www.sciencedirect.com/science/article/pii/S1674987114000425

Na-metasomatism in the form of albitisation is regionally extensive in the Precambrian crust of southern Scandinavia and is particularly widespread in the Bamble Sector, the Kongsberg-Modum Sector and the Norwegian part of the Mylonite Zone. Sites of albitisation outside these belts are associated with hy- drothermal breccia pipes and fracture-bound alteration. The albitites are composed of near end-member sodic plagioclase （Ano 5Ab94-99） with minor carbonate （calcite and dolomite）, rutile, clinopyroxene （En30Fs21-23W047 49）, amphibole （edenite-pargasite）, quartz, titanite, tourmaline, epidote （Fe3＋ - 0.20 -0.85 a.p.f.u） and chlorite （Mg# = 0.81-0.89）. The albitites have been studied in detail in the region around the town of Kragem, and are described as albitisation along veins, as breccias, alhitic felsites, massive carbonate-bearing albitites and megascale clinopyroxene-titanite-bearing albitite. The strong fluid control on their formation is illustrated by the veining and mineral replacement reactions, showing fluid transport by a H20-CO2 fluid rich in Na, depleting Fe and Mg from the host rock, in accordance with calculated mass transfer. A study of the mineralogical replacement reactions in combination with a regional compilation has demonstrated the relationship between metasomatic processes and the for- mation of apatite, ruti｜e and Fe deposits. The albitites occur spatially associated with other metasomatic rocks such as scapolitised metagabbros. We document that metasomatism is an important mineral- and rock-forming process in the continental crust, which in the Bamble Sector is a part of the tectonome- tamorphic evolution of the Sveconorwegian orogen.     

http://www.sciencedirect.com/science/article/pii/S1674987111001356

A total of 103 surface sediment samples collected from the water depth range of 15—3300 m along Vijaydurg-Karwar stretch of central west coast of India were analyzed for foraminiferal content. Relict benthic foraminiferal assemblage was noted within 50—135 m water depth.The relict benthic foraminiferal assemblage that includes Amphistegina,Operculum and Alveolinetta in sediment samples within the water depth of 85—135 m indicates presence of coral reef at this depth during Early Holocene. The presence of barnacle fouling on Relict foraminifera at 60—90 m confirms the paleo-shoreline. The shallow depth zone is characterized by presence of agglutinated relict foraminifera.The agglutinated forms indicate freshwater influx,which eventually increased the sea level and subsequently deteriorated the paleo-coral reef.     

http://www.sciencedirect.com/science/article/pii/S1674987113000339

The Mottled Zone(MZ) or Hatrurim Formation,which occurs near the Levantine Transform in the South Levant,has been studied during the last 150 years but its origin remains debatable.Mottled Zone Complex/Complexes(MZC/MZCs) consist of brecciated carbonate and low-temperature calcium-hydro-silicate rocks,which include unusual high- and ultra-high-temperature low-pressure(HT-LP) meta-morphic mineral assemblages.The MZ has been regarded as a product of combustion of bituminous chalks of the Ghareb Fm.of Cretaceous(Maastrichtian) age.In this paper we present detailed geographic, geomorphologic,structural and geological data from the MZCs of the South Levant,which show that the MZCs cannot be stratigraphically correlated with the Ghareb Fm.,because MZC late Oligocene-late Pleistocene deposits occur within or unconformable i.e.,with stratigraphic hiatus,overlap both the late Cretaceous and,in places,Neogene stratigraphic units.We propose an alternative model for the formation of MZCs by tectonically induced mud volcanism during late Oligocene-late Pleistocene time. This model explains(i) the presence of dikes and tube-like bodies,which consist of brecciated exotic clastic material derived from stratigraphically and hypsometrically lower horizons;(ii) mineral assemblages of sanidinite facies metamorphism;(iii) multi-stage character of HT-LP pyrometamorphism;and (iv) multi-stage low-temperature hydrothermal alteration.High temperatures(up to 1500℃) mineral assemblages resulted from combustion of hydrocarbon gases of mud volcanoes.Mud volcanism was spatially and structurally related to neotectonic folds and deformation zones formed in response to opening of the Red Sea rift and propagation of the Levantine Transform Fault.Our model may significantly change the prospects for oil-and-gas deposits in the region.     

http://www.sciencedirect.com/science/article/pii/S1674987110000071

<正>The lithospheric structure of China and its adjacent area is very complex and is marked by several prominent characteristics.Firstly,China's continental crust is thick in the west but thins to the east,and thick in the south but thins to the north.Secondly,the continental crust of the Qinghai—Tibet Plateau has an average thickness of 60—65 km with a maximum thickness of 80 km,whereas in eastern China the average thickness is 30—35 km,with a minimum thickness of only 5 km in the center of the South China Sea.The average thickness of continental crust in China is 47.6 km,which greatly exceeds the global average thickness of 39.2 km.Thirdly,as with the crust,the lithosphere of China and its adjacent areas shows a general pattern of thicker in the west and south,and thinner in the east and north.The lithosphere of the Qinghai—Tibet Plateau and northwestern China has an average thickness of 165 km, with a maximum thickness of 180—200 km in the central and eastern parts of the Tarim Basin,Pamir, and Changdu areas.In contrast,the vast areas to the east of the Da Hinggan Ling—Taihang—Wuling Mountains,including the marginal seas,are characterized by lithospheric thicknesses of only 50—85 km.Fourthly,in western China the lithosphere and asthenosphere behave as a "layered structure", reflecting their dynamic background of plate collision and convergence.The lithosphere and asthenosphere in eastern China display a "block mosaic structure",where the lithosphere is thin and the asthenosphere is very thick,a pattern reflecting the consequences of crustal extension and an upsurge of asthenospheric materials.The latter is responsible for a huge low velocity anomaly at a depth of 85—250 km beneath East Asia and the western Pacific Ocean.Finally,in China there is an age structure of "older in the upper layers and younger in the lower layers" between both the upper and lower crusts and between the crust and the lithospheric mantle.