Recent advances in three-dimensional numerical simulations of mantle convection have aided in approximately reproducing continental movement since the Pangea breakup at 200 Ma. These have also led to a better understa...Recent advances in three-dimensional numerical simulations of mantle convection have aided in approximately reproducing continental movement since the Pangea breakup at 200 Ma. These have also led to a better understanding of the thermal and mechanical coupling between mantle convection and surface plate motion and predictions of the configuration of the next supercontinent. The simulations of mantle convection from 200 Ma to the present reveals that the development of large-scale cold mantle downwellings in the North Tethys Ocean at the earlier stage of the Pangea breakup triggered the northward movement of the Indian subcontinent. The model of high temperature anomaly region beneath Pangea resulting from the thermal insulation effect support the breakup of Pangea in the real Earth time scale, as also suggested in previous geological and geodynamic models. However, considering the low radioactive heat generation rate of the depleted upper mantle, the high temperature anomaly region might have been generated by upwelling plumes with contribution of deep subducted TTG(tonalite-trondhjemite-granite) materials enriched in radiogenic elements. Integrating the numerical results of mantle convection from 200 Ma to the present, and from the present to the future, it is considered that the mantle drag force acting on the base of continents may be comparable to the slab pull force, which implies that convection in the shallower part of the mantle is strongly coupled with surface plate motion.展开更多
The mantle xenoliths in the Quaternary ChangbaishanVolcano in southern Jilin Province contain spinel-facies lherzolites. The equilibration temperatures for these samples range from 902℃ to 1064℃ based on the two-pyr...The mantle xenoliths in the Quaternary ChangbaishanVolcano in southern Jilin Province contain spinel-facies lherzolites. The equilibration temperatures for these samples range from 902℃ to 1064℃ based on the two-pyroxene thermometer of Brey and Kohler （1990）, and using the oxybarometry of Nell and Wood （1991）, the oxidation state was estimated from FMQ-1.32 to -0.38 with an average value of FMQ-0.81 （n = 8）, which is comparable to that of abyssal peridotites and the asthenospheric mantle. ThefO2 values of peridotites, together with their bulk rock compositions （e.g., Mg#, Al2O3, CaO, Ni, Co, Cr） and mineral compositions （e.g., Mg# of olivine and pyroxene, Cr# [=Cr/ [Cr＋Al]] and Mg# [=Mg/[Mg＋Fe2~] of spinel）, suggest that the present-day subcontinental lithospheric mantle （SCLM） beneath the Changbaishan Volcano most likely formed from an upwelling asthenosphere at some time after the late Mesozoic and has undergone a low degree of partial melting. The studied lherzolite xenoliths show low concentrations of S, Cu, and platinum group elements （PGE）, which plot a flat pattern on primitive-mantle normalized diagram. Very low concentrations in our samples suggest that PGEs occur as alloys or hosted by silicate and oxide minerals. The compositions of the studied samples are similar to those of peridotite xenoliths in the Longgang volcanic field （LVF） in their mineralogy and bulk rock compositions including the abundance of chalcophile and siderophile elements. However, they are distinctly different from those of peridotite xenoliths in other areas of the North China Craton （NCC） in terms of Cu, S and PGE. Our data suggest that the SCLM underlying the northeastern part of the NCC may represent a distinct unit of the newly formed lithospberic mantle.展开更多
We present a short review on the seismicity and crustmantle structure of the Indian subcontinent highlighting the major findings of the work done during the last few decades.Seismicity pattern and seismic power-law ch...We present a short review on the seismicity and crustmantle structure of the Indian subcontinent highlighting the major findings of the work done during the last few decades.Seismicity pattern and seismic power-law characteristics and the velocity structures studied by different techniques(seismic tomography,receiver function etc.)for various tectonic zones of the Indian subcontinent are summarized.In addition,some results on seismic anisotropy,seismic attenuation and ambient noise analyses are abridged.展开更多
Introduction Geology of the Indian subcontinent is not only diverse and interesting but also has been studied for a long period.Reflection of a rich geoscientific heritage may be illustrated by a couple of lesser know...Introduction Geology of the Indian subcontinent is not only diverse and interesting but also has been studied for a long period.Reflection of a rich geoscientific heritage may be illustrated by a couple of lesser known early or first“discoveries/descriptions”from the Indian subcontinent.Heinrich(1966)in his book“The Geology of Carbonatites”mentions that the first description of carbonatite was provided from India by Bose(1884)as quoted below(italics and bold for emphasis).展开更多
In Indian subcontinent one active volcano and another dormant volcano of Quaternary period are present in the Andaman Java subduction complex.The active Barren volcano throughout its history is erupting mainly tholeii...In Indian subcontinent one active volcano and another dormant volcano of Quaternary period are present in the Andaman Java subduction complex.The active Barren volcano throughout its history is erupting mainly tholeiitic basalt whereas the dormant Norcondam volcano is domal dacite and andesite volcano.In the Barren volcano wall,of 2km wide caldera is made up of prehistoric(~35 Ka)pyroclastics whereas the polygenetic tuff cone and valley fill are the products of historic(1787 yr)to recent activities of subaerial strombolian eruption and transient lava flows.展开更多
Cenozoc lavas from Hainan Island, bouth China, comprise quartz tholeiite. olivinethoeiite, alkali basalt, and basanite and form a continuous, thoeiite-dominated, comopitionalspectrum. Highly incompatible elements and ...Cenozoc lavas from Hainan Island, bouth China, comprise quartz tholeiite. olivinethoeiite, alkali basalt, and basanite and form a continuous, thoeiite-dominated, comopitionalspectrum. Highly incompatible elements and their relationships with isotope in these lavas areshown to be useful in evaluating mantle-source composition, whereas modeling suggests that ra-tios of elements with bulk partition coefficients significantly larger than those of Nb and Ta maybe sensitive to patial melting. Th/Ta and La/Nb ratios of alkali basalts are lower than those ofthoeiites, and they are all fower than tbe of the primitive mantle. These ratios correlate posi-tively with 207Pb/204Pb and 87Sr/86Sr ratios. Such relatioships can be explained by mixing ofdepleted and enriched source componentS. A depleted component is indicated by alkali basaltcompositions and is similar to some depleted OIB (PREMA). The enriched component, similarto sediment compositios, is indicated by tholeiites with high LILE/HFSE, 207Pb/204Pb, and87/86Sr ratios.In general, basalts from Hainan and the South China Basin (SCB) share common geo-chemical charcters, e.g. high Rb/Sr, Th/Ta, 207Pb/206Pb, and low Ba/Th ratios. Such ageochemical trend is comparable to that of EMII-type OIB and best explained as the result ofsubduction. Occurrence of these charcteristics in both continennd Hainan basalts and SCBseamount basalts indicates the presence of a South China geochemical domain that exists in themantle region below the lithosphere.展开更多
The determination of the formation age of subcontinental Lithosphere Mantle (SCLM) is a widely concerned issue in mantle geochemistry. it is difficult to obtain the formation age of SCLM using lithophile isotopic syst...The determination of the formation age of subcontinental Lithosphere Mantle (SCLM) is a widely concerned issue in mantle geochemistry. it is difficult to obtain the formation age of SCLM using lithophile isotopic systems such as Rb-Sr, Sm-Nd, U-Th-Pb, ete., but as siderophile elements, the Re-Os isotopic system provides a powerful tool for that work. Here a comprehensive review on the recent development in Re-Os dating for SCLM has been given.展开更多
The basalt-borne peridotite xenoliths from Jiangsu-Anhui provinces were analyzed for whole rock Os isotopic compositions in two laboratories of USTC, China and CRPG, France, respectively. The ^(187)Os/^(188)Os ratio o...The basalt-borne peridotite xenoliths from Jiangsu-Anhui provinces were analyzed for whole rock Os isotopic compositions in two laboratories of USTC, China and CRPG, France, respectively. The ^(187)Os/^(188)Os ratio of the sample set ranges from 0.119 to 0.129 (25 samples, USTC) and from 0.117 to 0.131 (17 samples, CRPG). The Os isotopic compositions of most samples are less than 0.129 and depleted relatively to the primitive mantle, showing a good correlation with the major element compositions. With the ^(187)Os/^(188)Os-AI2O3 alumichron, the samples yield a model age of 2.5±0.1 Ga (data of USTC) and 1.9±0.1 Ga (data of CRPG), late Archean to early Pro-terozoic. The two samples with the lowest ^(187)Os/^(188)Os ratio (0.119 and 0.117) have the T_(RD) (Re depleted age) of 1.1 Ga (USTC) and 1.4 Ga (CRPG), mid-Proterozoic. The Os isotope model age shows that the peridotite xenoliths from Cenozoic alkali basalt in Jiangsu-Anhui provinces have an old formation age (early- to mid- Proterozoic). They are not newly produced mantle after the Phanerozoic replacement of the lithosphere mantle, but residual fractions of Proterozoic mantle.展开更多
Recent seismic studies reveal a sharp velocity drop mostly at^70–100 km depth within the thick mantle keel beneath cratons, termed the mid-lithosphere discontinuity(MLD). The common presence of the MLD in cratonic re...Recent seismic studies reveal a sharp velocity drop mostly at^70–100 km depth within the thick mantle keel beneath cratons, termed the mid-lithosphere discontinuity(MLD). The common presence of the MLD in cratonic regions indicates structural and property layering of the subcontinental lithospheric mantle(SCLM). The nature and origin of the MLD, and many issues associated with the layering of the SCLM are essential to understand the formation and evolution of continents, and have become frontier subjects in the Earth sciences.展开更多
Background:Visceral leishmaniasis,commonly known as kala-azar in India,is a global public health problem.In Southeast Asia,Bangladesh,Bhutan,India,Nepal,Sri Lanka and Thailand are endemic for visceral leishmaniasis.Th...Background:Visceral leishmaniasis,commonly known as kala-azar in India,is a global public health problem.In Southeast Asia,Bangladesh,Bhutan,India,Nepal,Sri Lanka and Thailand are endemic for visceral leishmaniasis.The role of sandflies as the vector of kala-azar was first confirmed in 1942 in India.Insecticide resistance in Phlebotomus argentipes Annandale and Brunetti,the vector of kala-azar in the Indian subcontinent,was first reported in 1987 in Bihar,India.This article provides a scoping review of the studies undertaken from 1959 to 2015 on insecticide resistance in P.argentipes and P.papatasi(Scopoli),the vectors of visceral and cutaneous leishmaniasis respectively,in Southeast Asia,mainly in Bangladesh,India,Nepal and Sri Lanka.Results:Studies undertaken in areas of Bihar and West Bengal in India where kala-azar is endemic have reported resistance of P.argentipes to DDT,while in non-endemic areas it has been reported to be susceptible.In areas of Nepal bordering India,there are indications of resistance to DDT;biochemical resistance has been reported in Sri Lanka.No laboratory studies have been undertaken in Bangladesh;however,the sandfly vector is reported to be still susceptible to pyrethroids in all kala-azar endemic areas in the aforementioned countries.Conclusions:Studies are needed to determine the resistance of sandfly vectors to all available classes of potential insecticides in kala-azar endemic areas.There is a need to assess the impact of indoor residual spraying with DDT and pyrethroids on the incidence of kala-azar in India where 54 districts remain endemic for the disease,strengthen entomological surveillance capacity,and develop and implement an insecticide management plan.Alpha-cypermethrin indoor residual spraying has been introduced in 33 kala-azar endemic districts in Bihar State of India in a pilot trial;the outcomes should be used to inform decisions on expanding coverage with alpha-cypermethrin in all remaining endemic districts to achieve the revised goal of elimination of visceral leishmaniasis by 2020.展开更多
In the present paper,a global two-dimensional climate model developed by Chinese Academy of Meteorological Sciences (CAMS) with inclusion of a simple parameterization of land surface processes developed recently by Zh...In the present paper,a global two-dimensional climate model developed by Chinese Academy of Meteorological Sciences (CAMS) with inclusion of a simple parameterization of land surface processes developed recently by Zhang and Li is used to investigate the effect of vegetation cover of the Indian subcontinent on summer monsoon circulation and its rainfall. First of all,we carried out a control experiment in which the distribution of vegetation species was based on obser- vations.Then,with removal of the vegetation cover on the subcontinent,a sensitivity experiment was performed. For both of the experiments,the integrations were made from the beginning of April to the end of July.The results show that,after the vegetation was removed from the subcontinent,the monthly mean updraft and the monsoon circula- tion to the south of the Plateau was weakened in June and July.Especially,the change was more manifest in June.Also, in the south side of the Plateau,the easterly component was strengthened in the lower troposphere,the monsoon rainfall was reduced over the central India.Moreover,the rainfall was obviously reduced over the southern India from the end of June to the beginning of July.展开更多
With the support by the National Natural Science Foundation of China and the Chinese Academy of Sciences,the research team led by Prof.Li Jiatang(李家堂)at Chengdu Institute of Biology,Chinese Academy of Sciences,expl...With the support by the National Natural Science Foundation of China and the Chinese Academy of Sciences,the research team led by Prof.Li Jiatang(李家堂)at Chengdu Institute of Biology,Chinese Academy of Sciences,explored the biotic interchange between the Indian subcontinent and mainland展开更多
The components and evolution of subcontinental lithospheric mantle beneath the North China Craton and the Yangtze Craton is a current topic in the geological study of China and the carbon isotopic composition of diamo...The components and evolution of subcontinental lithospheric mantle beneath the North China Craton and the Yangtze Craton is a current topic in the geological study of China and the carbon isotopic composition of diamond is one of the most direct probes into cratonic lithospheric mantle processes.In this paper,in-situ SIMS(Secondary Ion Mass Spectrometry) techniques were used to analyze the carbon isotope compositions at different internal growth zones of diamonds from Shandong and Liaoning in the North China Craton and Hunan in the Yangtze Craton.It was found that the carbon isotopic range of diamonds from the North China Craton are rather distinct from those of the Yangtze Craton;the former has a range of 6.0‰ to 2.0‰(relative to VPDB) with an average value of 3.0‰ in their core areas,which is consistent with global peridotitic diamonds;the diamonds from the Yangtze Craton,however,have a carbon isotopic range from 8.6‰ to 3.0‰ with an average value of 7.4‰ in their core areas,being more consistent with global eclogitic diamonds.The variations of carbon isotope ratios between different internal growth zones in individual diamonds were different in the three diamond localities studied.There was a clear correlation between changes in carbon isotopic composition and phases of diamond dissolution and new growth,while no correlation was observed between δ13C and internal inclusions.The variations suggest that the carbon isotopic compositions of mantle fluids were changing during the process of diamond crystallization,and that the heterogeneity of the carbon isotopic composition in mantle carbon reservoirs was a more important factor than carbon isotope fractionation in controlling the carbon isotopic compositions and their variation in diamonds.In addition,the preliminary results of in-situ nitrogen analyses demonstrated that the variation of carbon isotopic compositions between the core and outer growth zones does not correlate with nitrogen abundances,implying either that diamonds crystallized in an open environment or that the carbon isotopic composition and nitrogen contents in mantle fluids were controlled by other,not yet understood factors.The experimental results provide hints that the isotopic composition of carbon and its original sources were different in metasomatic fluids controlling diamond formation in the mantle beneath the North China Craton and the Yangtze Craton.展开更多
Dinosaur discoveries from India have been known since 1844, while dinosaur discoveries from Pakistan have appeared recently since 2000. 3 large and 2 small theropod dinosaurs are known from Pakistan, while 11 large an...Dinosaur discoveries from India have been known since 1844, while dinosaur discoveries from Pakistan have appeared recently since 2000. 3 large and 2 small theropod dinosaurs are known from Pakistan, while 11 large and 4 small theropods are known from India. Pakistani land uncovered many footprints and trackways of Jurassic small and large theropods, Jurassic ankylosaur and Cretaceous hadrosaur ornithischian dinosaurs, while Indian land uncovered a footprint of small and a footprint of large theropod and 1 footprint of stegosaur. Pakistan uncovered a Jurassic bone taxon of ankylosaur ornithischian based on heavily armored synapomorphies. Recently, Pakistan yielded 1 bone taxon and 1 ichno taxon of pterosaurs, while Indian land yielded 1 bone taxon of pterosaur. Pakistani land uncovered 14 bone taxa (and 2 ichno taxa) of herbivorous sauropod dinosaurs, 5 bone taxa (and 2 ichnotaxa) of carnivorous theropod dinosaurs, 1 bone taxon of ankylosaur and 2 (ichnotaxa) of ornithischian (ankylosaur and hadrosaurs) dinosaurs, 1 bone taxon (and 1 ichno taxon) of pterosaurs, 1 plesiosaur, 7 crocodiles, 1 snake, 1 bird, 11 mammals, 3 fishes, 7 invertebrates and 1 plant. This study fills a significant gap in the literature by bringing together paleontological records from an understudied geographical location, enhancing the global understanding of dinosaur paleobiogeography. Pakistan hosts Precambrian to recent sediments igneous and metamorphic rocks. Pakistan is rich in mineral resources/rocks, but it needs more attention for its development to fulfill local requirements and earn foreign exchange.展开更多
First Published:2020 ISBN:9781421438740 Published by John Hopkins Press https://www.press.jhu.edu“The geological imagination of India,its landscapes,people,past and destiny,drive the narrative of this book”,Pratik C...First Published:2020 ISBN:9781421438740 Published by John Hopkins Press https://www.press.jhu.edu“The geological imagination of India,its landscapes,people,past and destiny,drive the narrative of this book”,Pratik Chakrabarti writes in his introduction to Inscriptions of Nature.His ambitious work examines the development of the natural and anthropological sciences on the Indian subcontinent since the early 19th century,and the shaping of knowledge about Indian nature through the exploration of its deep past:an exploration that dug not only into the depths of the earth,but also into ancient history,texts,myths,legends,folklore and the genealogies of local populations.This in-depth study not only combines the history of geology,paleontology,anthropology and ethnography,it also finely analyzes the interactions between the theoretical framework of scientific knowledge imported from Europe and local history,mythologies and indigenous beliefs.展开更多
文摘Recent advances in three-dimensional numerical simulations of mantle convection have aided in approximately reproducing continental movement since the Pangea breakup at 200 Ma. These have also led to a better understanding of the thermal and mechanical coupling between mantle convection and surface plate motion and predictions of the configuration of the next supercontinent. The simulations of mantle convection from 200 Ma to the present reveals that the development of large-scale cold mantle downwellings in the North Tethys Ocean at the earlier stage of the Pangea breakup triggered the northward movement of the Indian subcontinent. The model of high temperature anomaly region beneath Pangea resulting from the thermal insulation effect support the breakup of Pangea in the real Earth time scale, as also suggested in previous geological and geodynamic models. However, considering the low radioactive heat generation rate of the depleted upper mantle, the high temperature anomaly region might have been generated by upwelling plumes with contribution of deep subducted TTG(tonalite-trondhjemite-granite) materials enriched in radiogenic elements. Integrating the numerical results of mantle convection from 200 Ma to the present, and from the present to the future, it is considered that the mantle drag force acting on the base of continents may be comparable to the slab pull force, which implies that convection in the shallower part of the mantle is strongly coupled with surface plate motion.
基金supported by grants from National Natural Science Foundation of China (Nos.40873016,41173034,90814003)supportedby a grant from China Geological Survey (No.1212011121088)
文摘The mantle xenoliths in the Quaternary ChangbaishanVolcano in southern Jilin Province contain spinel-facies lherzolites. The equilibration temperatures for these samples range from 902℃ to 1064℃ based on the two-pyroxene thermometer of Brey and Kohler （1990）, and using the oxybarometry of Nell and Wood （1991）, the oxidation state was estimated from FMQ-1.32 to -0.38 with an average value of FMQ-0.81 （n = 8）, which is comparable to that of abyssal peridotites and the asthenospheric mantle. ThefO2 values of peridotites, together with their bulk rock compositions （e.g., Mg#, Al2O3, CaO, Ni, Co, Cr） and mineral compositions （e.g., Mg# of olivine and pyroxene, Cr# [=Cr/ [Cr＋Al]] and Mg# [=Mg/[Mg＋Fe2~] of spinel）, suggest that the present-day subcontinental lithospheric mantle （SCLM） beneath the Changbaishan Volcano most likely formed from an upwelling asthenosphere at some time after the late Mesozoic and has undergone a low degree of partial melting. The studied lherzolite xenoliths show low concentrations of S, Cu, and platinum group elements （PGE）, which plot a flat pattern on primitive-mantle normalized diagram. Very low concentrations in our samples suggest that PGEs occur as alloys or hosted by silicate and oxide minerals. The compositions of the studied samples are similar to those of peridotite xenoliths in the Longgang volcanic field （LVF） in their mineralogy and bulk rock compositions including the abundance of chalcophile and siderophile elements. However, they are distinctly different from those of peridotite xenoliths in other areas of the North China Craton （NCC） in terms of Cu, S and PGE. Our data suggest that the SCLM underlying the northeastern part of the NCC may represent a distinct unit of the newly formed lithospberic mantle.
文摘We present a short review on the seismicity and crustmantle structure of the Indian subcontinent highlighting the major findings of the work done during the last few decades.Seismicity pattern and seismic power-law characteristics and the velocity structures studied by different techniques(seismic tomography,receiver function etc.)for various tectonic zones of the Indian subcontinent are summarized.In addition,some results on seismic anisotropy,seismic attenuation and ambient noise analyses are abridged.
文摘Introduction Geology of the Indian subcontinent is not only diverse and interesting but also has been studied for a long period.Reflection of a rich geoscientific heritage may be illustrated by a couple of lesser known early or first“discoveries/descriptions”from the Indian subcontinent.Heinrich(1966)in his book“The Geology of Carbonatites”mentions that the first description of carbonatite was provided from India by Bose(1884)as quoted below(italics and bold for emphasis).
文摘In Indian subcontinent one active volcano and another dormant volcano of Quaternary period are present in the Andaman Java subduction complex.The active Barren volcano throughout its history is erupting mainly tholeiitic basalt whereas the dormant Norcondam volcano is domal dacite and andesite volcano.In the Barren volcano wall,of 2km wide caldera is made up of prehistoric(~35 Ka)pyroclastics whereas the polygenetic tuff cone and valley fill are the products of historic(1787 yr)to recent activities of subaerial strombolian eruption and transient lava flows.
文摘Cenozoc lavas from Hainan Island, bouth China, comprise quartz tholeiite. olivinethoeiite, alkali basalt, and basanite and form a continuous, thoeiite-dominated, comopitionalspectrum. Highly incompatible elements and their relationships with isotope in these lavas areshown to be useful in evaluating mantle-source composition, whereas modeling suggests that ra-tios of elements with bulk partition coefficients significantly larger than those of Nb and Ta maybe sensitive to patial melting. Th/Ta and La/Nb ratios of alkali basalts are lower than those ofthoeiites, and they are all fower than tbe of the primitive mantle. These ratios correlate posi-tively with 207Pb/204Pb and 87Sr/86Sr ratios. Such relatioships can be explained by mixing ofdepleted and enriched source componentS. A depleted component is indicated by alkali basaltcompositions and is similar to some depleted OIB (PREMA). The enriched component, similarto sediment compositios, is indicated by tholeiites with high LILE/HFSE, 207Pb/204Pb, and87/86Sr ratios.In general, basalts from Hainan and the South China Basin (SCB) share common geo-chemical charcters, e.g. high Rb/Sr, Th/Ta, 207Pb/206Pb, and low Ba/Th ratios. Such ageochemical trend is comparable to that of EMII-type OIB and best explained as the result ofsubduction. Occurrence of these charcteristics in both continennd Hainan basalts and SCBseamount basalts indicates the presence of a South China geochemical domain that exists in themantle region below the lithosphere.
文摘The determination of the formation age of subcontinental Lithosphere Mantle (SCLM) is a widely concerned issue in mantle geochemistry. it is difficult to obtain the formation age of SCLM using lithophile isotopic systems such as Rb-Sr, Sm-Nd, U-Th-Pb, ete., but as siderophile elements, the Re-Os isotopic system provides a powerful tool for that work. Here a comprehensive review on the recent development in Re-Os dating for SCLM has been given.
基金the National Natural Science Foundation of China (Grant Nos. 49837005 and 49733110).
文摘The basalt-borne peridotite xenoliths from Jiangsu-Anhui provinces were analyzed for whole rock Os isotopic compositions in two laboratories of USTC, China and CRPG, France, respectively. The ^(187)Os/^(188)Os ratio of the sample set ranges from 0.119 to 0.129 (25 samples, USTC) and from 0.117 to 0.131 (17 samples, CRPG). The Os isotopic compositions of most samples are less than 0.129 and depleted relatively to the primitive mantle, showing a good correlation with the major element compositions. With the ^(187)Os/^(188)Os-AI2O3 alumichron, the samples yield a model age of 2.5±0.1 Ga (data of USTC) and 1.9±0.1 Ga (data of CRPG), late Archean to early Pro-terozoic. The two samples with the lowest ^(187)Os/^(188)Os ratio (0.119 and 0.117) have the T_(RD) (Re depleted age) of 1.1 Ga (USTC) and 1.4 Ga (CRPG), mid-Proterozoic. The Os isotope model age shows that the peridotite xenoliths from Cenozoic alkali basalt in Jiangsu-Anhui provinces have an old formation age (early- to mid- Proterozoic). They are not newly produced mantle after the Phanerozoic replacement of the lithosphere mantle, but residual fractions of Proterozoic mantle.
基金supported by the National Natural Science Foundation of China (41225016, 41688103, 91414301)Chinese Academy of Sciences
文摘Recent seismic studies reveal a sharp velocity drop mostly at^70–100 km depth within the thick mantle keel beneath cratons, termed the mid-lithosphere discontinuity(MLD). The common presence of the MLD in cratonic regions indicates structural and property layering of the subcontinental lithospheric mantle(SCLM). The nature and origin of the MLD, and many issues associated with the layering of the SCLM are essential to understand the formation and evolution of continents, and have become frontier subjects in the Earth sciences.
文摘Background:Visceral leishmaniasis,commonly known as kala-azar in India,is a global public health problem.In Southeast Asia,Bangladesh,Bhutan,India,Nepal,Sri Lanka and Thailand are endemic for visceral leishmaniasis.The role of sandflies as the vector of kala-azar was first confirmed in 1942 in India.Insecticide resistance in Phlebotomus argentipes Annandale and Brunetti,the vector of kala-azar in the Indian subcontinent,was first reported in 1987 in Bihar,India.This article provides a scoping review of the studies undertaken from 1959 to 2015 on insecticide resistance in P.argentipes and P.papatasi(Scopoli),the vectors of visceral and cutaneous leishmaniasis respectively,in Southeast Asia,mainly in Bangladesh,India,Nepal and Sri Lanka.Results:Studies undertaken in areas of Bihar and West Bengal in India where kala-azar is endemic have reported resistance of P.argentipes to DDT,while in non-endemic areas it has been reported to be susceptible.In areas of Nepal bordering India,there are indications of resistance to DDT;biochemical resistance has been reported in Sri Lanka.No laboratory studies have been undertaken in Bangladesh;however,the sandfly vector is reported to be still susceptible to pyrethroids in all kala-azar endemic areas in the aforementioned countries.Conclusions:Studies are needed to determine the resistance of sandfly vectors to all available classes of potential insecticides in kala-azar endemic areas.There is a need to assess the impact of indoor residual spraying with DDT and pyrethroids on the incidence of kala-azar in India where 54 districts remain endemic for the disease,strengthen entomological surveillance capacity,and develop and implement an insecticide management plan.Alpha-cypermethrin indoor residual spraying has been introduced in 33 kala-azar endemic districts in Bihar State of India in a pilot trial;the outcomes should be used to inform decisions on expanding coverage with alpha-cypermethrin in all remaining endemic districts to achieve the revised goal of elimination of visceral leishmaniasis by 2020.
文摘In the present paper,a global two-dimensional climate model developed by Chinese Academy of Meteorological Sciences (CAMS) with inclusion of a simple parameterization of land surface processes developed recently by Zhang and Li is used to investigate the effect of vegetation cover of the Indian subcontinent on summer monsoon circulation and its rainfall. First of all,we carried out a control experiment in which the distribution of vegetation species was based on obser- vations.Then,with removal of the vegetation cover on the subcontinent,a sensitivity experiment was performed. For both of the experiments,the integrations were made from the beginning of April to the end of July.The results show that,after the vegetation was removed from the subcontinent,the monthly mean updraft and the monsoon circula- tion to the south of the Plateau was weakened in June and July.Especially,the change was more manifest in June.Also, in the south side of the Plateau,the easterly component was strengthened in the lower troposphere,the monsoon rainfall was reduced over the central India.Moreover,the rainfall was obviously reduced over the southern India from the end of June to the beginning of July.
文摘With the support by the National Natural Science Foundation of China and the Chinese Academy of Sciences,the research team led by Prof.Li Jiatang(李家堂)at Chengdu Institute of Biology,Chinese Academy of Sciences,explored the biotic interchange between the Indian subcontinent and mainland
基金supported by the Public Research Project of the Ministry of Land and Resources of the People’s Republic of China(200811012)the National Natural Science Foundation of China(41272086)
文摘The components and evolution of subcontinental lithospheric mantle beneath the North China Craton and the Yangtze Craton is a current topic in the geological study of China and the carbon isotopic composition of diamond is one of the most direct probes into cratonic lithospheric mantle processes.In this paper,in-situ SIMS(Secondary Ion Mass Spectrometry) techniques were used to analyze the carbon isotope compositions at different internal growth zones of diamonds from Shandong and Liaoning in the North China Craton and Hunan in the Yangtze Craton.It was found that the carbon isotopic range of diamonds from the North China Craton are rather distinct from those of the Yangtze Craton;the former has a range of 6.0‰ to 2.0‰(relative to VPDB) with an average value of 3.0‰ in their core areas,which is consistent with global peridotitic diamonds;the diamonds from the Yangtze Craton,however,have a carbon isotopic range from 8.6‰ to 3.0‰ with an average value of 7.4‰ in their core areas,being more consistent with global eclogitic diamonds.The variations of carbon isotope ratios between different internal growth zones in individual diamonds were different in the three diamond localities studied.There was a clear correlation between changes in carbon isotopic composition and phases of diamond dissolution and new growth,while no correlation was observed between δ13C and internal inclusions.The variations suggest that the carbon isotopic compositions of mantle fluids were changing during the process of diamond crystallization,and that the heterogeneity of the carbon isotopic composition in mantle carbon reservoirs was a more important factor than carbon isotope fractionation in controlling the carbon isotopic compositions and their variation in diamonds.In addition,the preliminary results of in-situ nitrogen analyses demonstrated that the variation of carbon isotopic compositions between the core and outer growth zones does not correlate with nitrogen abundances,implying either that diamonds crystallized in an open environment or that the carbon isotopic composition and nitrogen contents in mantle fluids were controlled by other,not yet understood factors.The experimental results provide hints that the isotopic composition of carbon and its original sources were different in metasomatic fluids controlling diamond formation in the mantle beneath the North China Craton and the Yangtze Craton.
文摘Dinosaur discoveries from India have been known since 1844, while dinosaur discoveries from Pakistan have appeared recently since 2000. 3 large and 2 small theropod dinosaurs are known from Pakistan, while 11 large and 4 small theropods are known from India. Pakistani land uncovered many footprints and trackways of Jurassic small and large theropods, Jurassic ankylosaur and Cretaceous hadrosaur ornithischian dinosaurs, while Indian land uncovered a footprint of small and a footprint of large theropod and 1 footprint of stegosaur. Pakistan uncovered a Jurassic bone taxon of ankylosaur ornithischian based on heavily armored synapomorphies. Recently, Pakistan yielded 1 bone taxon and 1 ichno taxon of pterosaurs, while Indian land yielded 1 bone taxon of pterosaur. Pakistani land uncovered 14 bone taxa (and 2 ichno taxa) of herbivorous sauropod dinosaurs, 5 bone taxa (and 2 ichnotaxa) of carnivorous theropod dinosaurs, 1 bone taxon of ankylosaur and 2 (ichnotaxa) of ornithischian (ankylosaur and hadrosaurs) dinosaurs, 1 bone taxon (and 1 ichno taxon) of pterosaurs, 1 plesiosaur, 7 crocodiles, 1 snake, 1 bird, 11 mammals, 3 fishes, 7 invertebrates and 1 plant. This study fills a significant gap in the literature by bringing together paleontological records from an understudied geographical location, enhancing the global understanding of dinosaur paleobiogeography. Pakistan hosts Precambrian to recent sediments igneous and metamorphic rocks. Pakistan is rich in mineral resources/rocks, but it needs more attention for its development to fulfill local requirements and earn foreign exchange.
文摘First Published:2020 ISBN:9781421438740 Published by John Hopkins Press https://www.press.jhu.edu“The geological imagination of India,its landscapes,people,past and destiny,drive the narrative of this book”,Pratik Chakrabarti writes in his introduction to Inscriptions of Nature.His ambitious work examines the development of the natural and anthropological sciences on the Indian subcontinent since the early 19th century,and the shaping of knowledge about Indian nature through the exploration of its deep past:an exploration that dug not only into the depths of the earth,but also into ancient history,texts,myths,legends,folklore and the genealogies of local populations.This in-depth study not only combines the history of geology,paleontology,anthropology and ethnography,it also finely analyzes the interactions between the theoretical framework of scientific knowledge imported from Europe and local history,mythologies and indigenous beliefs.
