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/S1674987113000388

The AravallieDelhi and Satpura Mobile Belts(ADMB and SMB)and the Eastern Ghat Mobile Belt(EGMB)in India form major Proterozoic mobile belts with adjoining cratons and contemporary basins.The most convincing features of the ADMB and the SMB have been the crustal layers dipping from both sides in opposite directions,crustal thickening(w45 km)and high density and high conductivity rocks in upper/lower crust associated with faults/thrusts.These observations indicate convergence while domal type refectors in the lower crust suggest an extensional rifting phase.In case of the SMB,even the remnant of the subducting slab characterized by high conductive and low density slab in lithospheric mantle up to w120 km across the PurnaeGodavari river faults has been traced which may be caused by fuids due to metamorphism.Subduction related intrusives of the SMB south of it and the ADMB west of it suggest NeS and EeW directed convergence and subduction during MesoeNeoproterozoic convergence.The simultaneous EeW convergence between the Bundelkhand craton and Marwar craton(Western Rajasthan)across the ADMB and the NeS convergence between the Bundelkhand craton and the Bhandara and Dharwar cratons across the SMB suggest that the forces of convergence might have been in a NEeSW direction with EeW and NeS components in the two cases,respectively.This explains the arcuate shaped collision zone of the ADMB and the SMB which are connected in their western part.The Eastern Ghat Mobile Belt(EGMB)also shows signatures of E eW directed MesoeNeoproterozoic convergence with East Antarctica similar to ADMB in north India.Foreland basins such as Vindhyan(ADMBeSMB),and Kurnool(EGMB)Supergroups of rocks were formed during this convergence.Older rocks such as Aravalli(ADMB),MahakoshaleBijawar(SMB),and Cuddapah(EGMB)Supergroups of rocks with several basic/ultrabasic intrusives along these mobile belts,plausibly formed during an earlier episode of rifting during PaleoeMesoproterozoic period.They are highly disturbed and deformed due to subsequent MesoeNeoproterozoic convergence.As these Paleoproterozoic basins are characterized by large scale basic/ultrabasic intrusives that are considerably wide spread,it is suggested that a plume/superplume might have existed under the Indian cratons at that time which was responsible for the breakup of these cratons.Further,the presence of older intrusives in these mobile belts suggests that there might have been some form of convergence also during Paleoproterozoic period.     

http://www.sciencedirect.com/science/article/pii/S1674987113001114

The Deccan Syneclise is considered to have significant hydrocarbon potential.However,significant hydrocarbon discoveries,particularly for Mesozoic sequences,have not been established through conventional exploration due to the thick basalt cover over Mesozoic sedimentary rocks.In this study,near-surface geochemical data are used to understand the petroleum system and also investigate type of source for hydrocarbons generation of the study area.Soil samples were collected from favorable areas identified by integrated geophysical studies.The compositional and isotopic signatures of adsorbed gaseous hydrocarbons(methane through butane) were used as surface indicators of petroleum micro-seepages.An analysis of 75 near-surface soil-gas samples was carried out for light hydrocarbons(C1-C4) and their carbon isotopes from the western part of Tapti graben,Deccan Syneclise,India.The geochemical results reveal sites or clusters of sites containing anomalously high concentrations of light hydrocarbon gases.High concentrations of adsorbed thermogenic methane(C_1 = 518 ppb) and ethane plus higher hydrocarbons(ΣC_(2+) = 977 ppb) were observed.Statistical analysis shows that samples from 13% of the samples contain anomalously high concentrations of light hydrocarbons in the soil-gas constituents.This seepage suggests largest magnitude of soil gas anomalies might be generated/source from Mesozoic sedimentary rocks,beneath Deccan Traps.The carbon isotopic composition of methane,ethane and propane ranges are from-22.5‰ to-30.2‰ PDB,-18.0‰to 27.1‰ PDB and 16.9‰-32.1‰ PDB respectively,which are in thermogenic source.Surface soil sample represents the intersection of a migration conduit from the deep subsurface to the surface connected to sub-trappean Mesozoic sedimentary rocks.Prominent hydrocarbon concentrations were associated with dykes,lineaments and presented on thinner basaltic cover in the study area,which probably acts as channel for the micro-seepage of hydrocarbons.     

http://www.sciencedirect.com/science/article/pii/S1674987111000466

The Ordos Basin of North China is not only an important uranium mineralization province, but also a major producer of oil,gas and coal in China.The genetic relationship between uranium mineralization and hydrocarbons has been recognized by a number of previous studies,but it has not been well understood in terms of the hydrodynamics of basin fluid flow.We have demonstrated in a previous study that the preferential localization of Cretaceous uranium mineralization in the upper part of the Ordos Jurassic section may have been related to the interface between an upward flowing,reducing fluid and a downward flowing,oxidizing fluid.This interface may have been controlled by the interplay between fluid overpressure related to disequilibrium sediment compaction and which drove the upward flow,and topographic relief,which drove the downward flow.In this study,we carried out numerical modeling for the contribution of oil and gas generation to the development of fluid overpressure,in addition to sediment compaction and heating.Our results indicate that when hydrocarbon generation is taken into account,fluid overpressure during the Cretaceous was more than doubled in comparison with the simulation when hydrocarbon generation was not considered.Furthermore,fluid overpressure dissipation at the end of sedimentation slowed down relative to the no-hydrocarbon generation case.These results suggest that hydrocarbon generation may have played an important role in uranium mineralization,not only in providing reducing agents required for the mineralization,but also in contributing to the driving force to maintain the upward flow.     

http://www.sciencedirect.com/science/article/pii/S1674987114001303

We show the presence of fractal ordering of copper grade in bore core data at short range in the Cadia Ridgeway porphyry deposit and measure its persistence after mining by monitoring the output of the...     

http://www.sciencedirect.com/science/article/pii/S167498711000040X

The Eastern Pontides orogenic belt in the Black Sea region of Turkey offers a critical window to plate kinematics and subduction polarity during the closure of the Paleotethys. Here we provide a brief synthesis on recent information from this belt. We infer a southward subduction for the origin of the Eastern Pontides orogenic belt and its associated late Mesozoic–Cenozoic magmatism based on clear spatial and temporal variations in Late Cretaceous and Cenozoic arc magmatism, together with the existence of a prominent south-dipping reverse fault system along the entire southern coast of the Black Sea. Our model is at variance with some recent proposals favoring a northward subduction polarity, and illustrates the importance of arc magmatism in evaluating the geodynamic milieu associated with convergent margin processes.     

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/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/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/S1674987111001307

South China Sea(SCS) is the largest Western Pacific marginal sea.However,microbial studies have never been performed in the cold seep sediments in the SCS.In 2004."SONNE" 177 cruise found two cold seep areas with different water depth in the northern SCS.Haiyang 4 area,where the water depth is around 3000 m.has already been confirmed for active seeping on the seafloor.such as microbial mats,authigenic carbonate crusts and bivalves.We investigated microbial abundance and diversity in a 5.55-111 sediment core collected from this cold seep area.An integrated approach was employed including geochemistry and 16S rRNA gene phylogenetic analyses.Here,we show that microbial abundance and diversity along with geochemistry profiles of the sediment core revealed a coupled reaction between sulphate reduction and methane oxidation.Acridine orange direct count results showed that microbial abundance ranges from 10~5 to 10~6 cells/g sediment(wet weight).The depth-related variation of the abundance showed the same trend as the methane concentration profile.Phylogenetic analysis indicated the presence of sulphate-reducing bacteria and anaerobic methane-oxidizing archaea.The diversity was much higher at the surface,but decreased sharply with depth in response to changes in the geochemical conditions of the sediments,such as methane,sulphate concentration and total organic carbon.Marine Benthic Group B.Chloroflexi and JSl were predominant phylotypes of the archaeal and bacterial libraries,respectively.     

http://www.sciencedirect.com/science/article/pii/S1674987111001009

The North Yellow Sea Basin is a Mesozoic and Cenozoic basin.Based on basin-margin facies,sedimentary thinning,size and shape of the basin and vitrinite reflectance.North Yellow Sea Basin is not a residual basin.Analysis of the development of the basin’s three structural layers,self-contained petroleum systems,boundary fault activity,migration of the Mesozoie—Cenozoic sedimentation centers, different basin structures formed during different periods,and superposition of a two-stage extended basin and one-stage depression basin,the North Yellow Sea Basin is recognized as a superimposed basin.     

http://www.sciencedirect.com/science/article/pii/S1674987112000618

The Moyar Shear Zone(MSZ) of the South Indian granulite terrain hosts a prominent syenite pluton (～560 Ma) and associated NW-SE to NE-SW trending mafic dyke swarm(～65 Ma and 95 Ma). Preliminary magnetic fabric studies in the mafic dykes,using Anisotropy of Magnetic Susceptibly(AMS) studies at low-field,indicate successive emplacement and variable magma flow direction.Magnetic lineation and foliation in these dykes are identical to the mesoscopic fabrics in MSZ mylonites,indicating shear zone guided emplacement.Spatial distribution of magnetic lineation in the dykes suggests a common conduit from which the source magma has been migrated.The magnetic foliation trajectories have a sigmoidal shape to the north of the pluton and curve into the MSZ suggesting dextral sense of shear.Identical fabric conditions for magnetic fabrics in the syenite pluton and measured field fabrics in mylonite indicate syntectonic emplacement along the Proterozoic crustal scale dextral shear zone with repeated reactivation history.     

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/S1674987112000886

Six national-scale, or near national-scale, geochemical data sets for soils or stream sediments exist for the United States. The earliest of these, here termed the ‘Shacklette’ data set, was generated by a U.S. Geological Survey (USGS) project conducted from 1961 to 1975. This project used soil collected from a depth of about 20 cm as the sampling medium at 1323 sites throughout the conterminous U.S. The National Uranium Resource Evaluation Hydrogeochemical and Stream Sediment Reconnaissance (NURE-HSSR) Program of the U.S. Department of Energy was conducted from 1975 to 1984 and collected either stream sediments, lake sediments, or soils at more than 378,000 sites in both the conterminous U.S. and Alaska. The sampled area represented about 65% of the nation. The Natural Resources Conservation Service (NRCS), from 1978 to 1982, collected samples from multiple soil horizons at sites within the major crop-growing regions of the conterminous U.S. This data set contains analyses of more than 3000 samples. The National Geochemical Survey, a USGS project conducted from 1997 to 2009, used a subset of the NURE-HSSR archival samples as its starting point and then collected primarily stream sediments, with occasional soils, in the parts of the U.S. not covered by the NURE-HSSR Program. This data set contains chemical analyses for more than 70,000 samples. The USGS, in collaboration with the Mexican Geological Survey and the Geological Survey of Canada, initiated soil sampling for the North American Soil Geochemical Landscapes Project in 2007. Sampling of three horizons or depths at more than 4800 sites in the U.S. was completed in 2010, and chemical analyses are currently ongoing. The NRCS initiated a project in the 1990s to analyze the various soil horizons from selected pedons throughout the U.S. This data set currently contains data from more than 1400 sites. This paper (1) discusses each data set in terms of its purpose, sample collection protocols, and analytical methods; and (2) evaluates each data set in terms of its appropriateness as a national-scale geochemical database and its usefulness for national-scale geochemical mapping.     

http://www.sciencedirect.com/science/article/pii/S1674987111000193

Geochemical subsoil data obtained from China and European laboratories have been compared in this study. 787 C horizon subsoil samples from FOREGS (Forum of European Geological Surveys) geochemical baselines mapping project were sent to China’s IGGE (Institute of Geophysical and Geochemical Exploration) laboratory and composited to 190 samples according to the 160 km 160 km GNT (Global Terrestrial Network) cells. In addition to the FOREGS elemental analysis package, Au, Pt, Pd, B, Ge, Br, Cl, Se, N, Li and F were also analyzed by using the IGGE’s 76 element analytical scheme. Geochemical data statistics, scatter plotting, and geochemical map compilation techniques have been employed to investigate differences between FOREGS and IGGE analytical results. The results of two datasets, the IGGE’s analysis data for composited samples, and the FOREGS average data of samples in each GNT cell, agree extremely well for about 23 elements, viz: SiO2, Sr, Al2O3, Zr, Ba, Fe2O3, Ti, Rb, Mn, Gd, CaO, Ga, MgO, P, Pb, Na2O, Y, Th, As, U Sc, Cr, and Co. There are slight differences between-laboratory biases shown as proportional errors between the datasets for Ni, K2O, Tb, Tl, Cu, S, Sm, La, Ce, Pr, Nd, Eu, Ho, Er, Tm, Yb, Lu, Ta, Nb, Hf, and Dy. For Cd, Cs, Be, Sb, In, Mo, I, Sn, and Te, the correlation of the two datasets and the similarity of the geochemical maps are fairly good, but obvious biases exist between the two datasets at values near detection limits. Sensitivities of FOREGS analytical methods for W, Bi, Sn, Te, Be, and I are insufficient to produce reportable values in at least 80% of the samples. Although the detection limits of Ag for both FOREGS and IGGE are sufficient to provide reportable values, a large bias was found between the two datasets. This study demonstrates that consistent analytical data for certain elements of global geochemical mapping samples can be achieved by different qualified laboratories, such as China’s IGGE laboratory and some European laboratories. For some elements, such as Ag, further research on the selection of the proper analytical methods and on the development of quality control methods should be undertakendwith final recommendations adhered to by all participants of the global geochemical mapping program.     

http://www.sciencedirect.com/science/article/pii/S1674987114000644

正1.Introduction This special issue of Geoscience Frontiers is a tribute volume honoring the life and career of Jacques Touret.A set of research papers has been assembled,which broadly reflect his research interests over his 50 plus year career.These papers focus on the role that fluids play during the formation and evolution of the Earth's crust.Below I provide a brief summary of the life of Jacques Touret,along with a select bibliography of his more important papers.This is then followed by a brief introduction to the papers assembled for this special issue.     

http://www.sciencedirect.com/science/article/pii/S1674987112000679

Quasi-integrity of continental crust between Mid-Archaean and Ediacaran times is demonstrated by conformity of palaeomagnetic poles to near-static positions between～2.7-2.2 Ca,～1.5-1.2 Ga and～0.75-0.6 Ga.Intervening data accord to coherent APW loops turning at "hairpins" focused near a continental-centric location.Although peripheral adjustments occurred during Early Proterozoic （～2.2 Ga） and Grenville（～1.1 Ga） times,the crust retained a low order symmetrical crescent-shaped form constrained to a single global hemisphere until break-up in Ediacaran times.Conformity of palaeomagnetic data to specific Eulerian parameters enables definition of a master Precambrian APW path used to estimate the root mean square velocity(v_RMS) of continental crust between 2.8 and 0.6 Ga.A long interval of little polar movement between～2.7 and 2.2 Ga correlates with global magmatic shutdown between～2.45 and 2.2 Ga,whilst this interval and later slowdown at～0.75-0.6 Ga to velocities of <2 cm/year correlate with episodes of widespread glaciation implying that these prolonged climatic anomalies had an internal origin;the reduced input of volcanically-derived atmospheric greenhouse gases is inferred to have permitted freeze-over conditions with active ice sheets extending into equatorial latitudes as established by low magnetic inclinations in glaciogenic deposits.v_RMS variations through Precambrian times correspond to the distribution of U-Pb ages in orogenic granitoids and detrital zircons and demonstrate that mobility of continental crust has been closely related to crustal tectonism and incrementation.Both periods of near-stillstand were followed by rapid v_RMS recording massive heat release from beneath the continental lid at～2.2 and 0.6 Ga.The first coincided with the Lomagundi-Jatuli isotopic event and led to prolonged orogenesis accompanied by continental flooding and reconfiguration of the crust on the Earth’s surface;the second led to continental break-up and instigated the comprehensive Plate Tectonics that has characterised Phanerozoic times.The Mesoproterozoic interval characterised by anorogenic magmatism correlates with low v_RMS between～1.5 and 1.1 Ga.Insulation of the sub-continental mantle evidently permitted high temperature melting and weakening of the crustal lid to enable buoyant emplacement of large plutons at high crustal levels during this magmatic event unique to Mesoproterozoic and early Neoproterozoic times.     

A review of the ～1600 Ma sedimentation, volcanism, and tectono-thermal events in the Singhbhum craton, Eastern India

The Palaeoproterozoic–Mesoproterozoic transition (～1600 Ma) is a significant event in the Earth history as a global thermal perturbation affected the pre-1600 Ma landmasses. Like other cratonic blocks of the world, lithospheric thinning, sedimentation, magmatism, metamorphism and crustal melting/anatexis are associated with this significant geological event in the Singhbhum cratonic province of India. This paper is a review of sedimentological, magmatic and tectono-thermal events in the Singhbhum craton at ～1600 Ma. The Palaeo-Mesoproterozoic sedimentation and volcanism in the Singhbhum craton took place in a terrestrial intracontinental rift setting. The available geochronological data are indicative of late Palaeoproterozoic to Neoproterozoic tectono-thermal events in the Chhotanagpur Granite Gneissic Complex (CGGC), an east–west trending arcuate belt of granite gneisses, migmatites and metasedimentary rocks. A detailed multidisciplinary geo-scientific investigation of the Dalma volcanic belt and the area to its north (Chandil Formation) and further north in CGGC will enable us to constrain the extant surface processes and crust-mantle interactions, the collision events between the North and South Indian cratonic blocks, and the position of India in the Columbia supercontinent.     

http://www.sciencedirect.com/science/article/pii/S1674987111000545

By applying the ’theory of synchronization’ from the science of complexity to studying the regional regularity of ore formation within the Nanling region of southern China,a characteristic target-pattern regional ore zonality has been discovered.During the early and late Yanshanian epoch(corresponding respectively to the Jurassic and Cretaceous periods),two centers of ore formation emerged successively in the Nanling region;the former is mainly for rare metals(W,Sn,Mo,Bi,Nb) and one rare-earth element (La) and was generated in the Jurassic period;whereas the latter is mainly for base metals(Cu,Pb,Zn,Sb, Hg),noble metals(Au,Ag),and one radioactive element(U) and was generated in the Cretaceous period. Centers of ore formation were brought about by interface dynamics respectively at the Qitianling and Jiuyishan districts in southern Hunan Province.The characteristic giant nonlinear target-pattern regional ore zonality was generated by spatio-temporal synchronization process of the Nanling complex metallo-genic system.It induced the collective dynamics and cooperative behavior of the system and displayed the configuration of the regional ore zonality.Then dynamical clustering transformed the configuration into rudimentary ordered coherent structures.Phase dynamics eventually defined the spatio-temporal structures of the target-pattern regional ore zonality and determined their localization and distribution.A new methodology for revealing regional ore zonality is developed,which will encourage further investigation of the formation of deep-seated ore resources and the onset of large-scale mineralization.