Genesis of the Jiajika superlarge lithium deposit,Sichuan,China:constraints from He–Ar–H–O isotopes

The Jiajika granitic-and pegmatite-type lithium deposit,which is in the Songpan-Garze Orogenic Belt in western Sichuan Province,China,is the largest in Asia.Previous studies have examined the geochemistry and mineralogy of pegmatites and their parental source rocks to determine the genesis of the deposit.However,the evolution of magmatic-hydrothermal fluids has received limited attention.We analyzed He–Ar–H–O isotopes to decipher the ore-fluid nature and identify the contribution of fluids to mineralization in the late stage of crystallization differentiation.In the Jiajika ore field,two-mica granites,pegmatites(including common pegmatites and spodumene pegmatites),metasandstones,and schists are the dominant rock types exposed.Common pegmatites derived from early differentiation of the two-mica granitic magmas before they evolved into spodumene pegmatites during the late stage of the magmatic evolution.Common pegmatites have~3He/~4He ratios that vary from 0.18 to 4.68 Ra(mean1.62 Ra),and their~(40)Ar/~(36)Ar ratios range from 426.70 to 1408.06(mean 761.81);spodumene pegmatites have~3He/~4He ratios that vary from 0.18 to 2.66 Ra(mean 0.87Ra)and their~(40)Ar/~(36)Ar ratios range from 402.13 to 1907.34(mean 801.65).These data indicate that the hydrothermal fluids were shown a mixture of crust-and mantle-derived materials,and the proportion of crustderived materials in spodumene pegmatites increases significantly in the late stage of the magmatic evolution.Theδ~(18)OH_(2)O–VSMOWvalues of common pegmatites range from 6.2‰to 10.9‰,with a mean value of 8.6‰,andδDV–SMOWvalues vary from-110‰to-72‰,with a mean o f-85‰.Theδ~(18)OH_(2)O–VSMOWvalues of spodumene pegmatites range from 5.3‰to 13.2‰,with a mean of 9.1‰,andδDV–SMOWvalues vary from-115‰to-77‰,with a mean of-91‰.These data suggest that the ore-forming fluids came from primary magmatic water gradually mixing with more meteoric water in the late stage of the magmatic evolution.Based on the He–Ar–H–O and other existing data,we propose that the oreforming metals are mainly derived from the upper continental crust with a minor contribution from the mantle,and the fluid exsolution and addition of meteoric water during the formation of pegmatite contributed to the formation of the Jiajika superlarge lithium deposit.

Trace-element geochemistry and S–O isotopes in the fluorite-barite mineralization of Merguechoum,Moroccan eastern Meseta:insights into ore genesis to the Pangea rifting

The Merguechoum fluorite-barite mineralization,located in the Eastern Meseta of Morocco,is hosted in the Late Hercynian granite.The ore consists of fine crystals of fluorite 1,massive barite 1,euhedral crystals of fluorite 2,and barite 2 with calcite and minor quartz and sulfides.The Merguechoum ore deposits have never been investigated.This study was the first contribution that studied the genesis of fluorite and barite.The ore occurs as dissemination within granite intrusion and also fills the NE-SWtrending meter-sized fractures and faults.The values of the total Rare Earth Elements and Yttrium(REY)and the ratios of LREY/HREY,Y/Ho,Tb/Ca,and Tb/La indicate that the Merguechoum fluorite precipitated from hydrothermal fluids,likely basinal brines,which interacted with the Hercynian granite.The REY data indicate that the ore-forming fluids of the early stage have intensely interacted with the Hercynian granite compared to those of the late ore stage.The gradual decrease in the europium(Eu/Eu^(*)),yttrium(Y/Y^(*)),and cerium(Ce/Ce^(*))anomalies and a low concentration ofΣREY observed in the second ore stage compared to the first ore stage suggest an increase in p H and fO_(2)and by inference a decrease in temperature during the evolution of the hydrothermal system.This evolution could be explained by fluid mixing between the ascending basinal hydrothermal fluids and the diluted sulfate-rich meteoric water barite separates from selected samples reveal that the dissolved sulfates(SO_(4)^(2-))were derived from Permian–Triassic sulfates and/or coeval poreseawater sulfates.The proposed fluid mixing triggered the precipitation of an early-stage F-Ba assemblage followed by the second-stage F-Ba mineralization.Geologic fieldwork,REY inventories,and isotope data point to the ore genesis during the Permian–Triassic extensional tectonic activity concerning the Pangea rifting.This extensional tectonic environment is likely the driving force that mobilized a large amount of the ore-forming basinal brines along the available faults and fractures to the loci of ore deposition.

A Study of Sr, Nd and O Isotopes of the K-rich Melanocratic Dykes in the Late Mesozoic Gold Field in the Jiaodong Peninsula

Geologic, petrographic and petrochemical studies of the lateMesozoic K-rich melanocratic dykes, including lamprophyres, andesite porphyrites and dacite-porphyry in the gold field system in the Jiaodong Peninsula, China, have shown that these dykes are characterized by rich potassium and alkali but poor titanium. They belong to an ultra-high potassic, shoshonitic and high potassic calc-alkaline rock series. The parental magma has relatively high initial strontium ratios ((87Sr/86Sr)i-0.70895-0.71140) and low (143Nd/144Nd)i ratios (varying from 0.51135 to 0.51231); and its δ18OsMow. whole rock values vary from +5.8‰ to +10.6‰ with a mean of +7.1‰. These features suggest that the source region of the magma is an enriched mantle wedge transformed from a continental lithosphere mantle which has experienced me tasomatism by mantle-derived fluids with H2O-dominated fluids that were provided during the underthrusting of an ocean crust. The initial magma was generated by low-degree partial melting of the enriched mantle in its mature stage in the back-arc spreading environment. The evolution of magmas is associated with two trends, i.e., fractional crystallization and mixing with or intensive contamination by palaeo-crust materials or metamorphic rocks. The former process is evident in the gold field system of quartz-vein type, whereas the latter is dominated in the gold field system of the altered-rock type. This conclusion is very important for more detailed study of petrogenesis and mineralization through the crust-mantle interaction (exchange) in the Mesozoic in this region.

Geochemistry of the Aptian bituminous limestones in Gümuü?hane area,Eastern Black Sea region:new insight into paleogeography and paleoclimate conditions

Aptian is characterized by widespread deposition of organic-rich sediment.The Aptian bitumen limestone horizon,which is thin decimetre-thick sequences,locally crops out in the Kircaova area,Eastern Black Sea Region(Eastern Pontides).They are well correlated with Aptian bitumen limestone in the other Tethys Reams.They are proposed as episodes of increased organic matter.However,background factors controlling organic matter enrichment are poorly known.In this study,we present new inorganic geochemistry,including trace elements,rare earth elements(REE),redox-sensitive elements(RSE),stable-isotopes(δ~(18)O andδ~(13)C),and total organic carbon(TOC).We integrated new geochemical data with existing stratigraphy,paleontology,and organic chemistry data to provide new insight into the depositional environment and paleoclimate conditions during Aptian.The lacustrine bitumen limestone(LBL)samples have variedδ~(13)C(ave.-1.45‰)andδ~(18)O(ave.-4.50‰).They possess distinct REE patterns,with an average of REE(ave.14.45 ppm)and Y/Ho(ave.35)ratios.In addition,they have variable Nd/YbN(0.28-0.81;ave.0.56)and Ce/Ce*(0.68-0.97;ave.0.86),and relatively high Eu^(*)/Eu(1.23-1.53;ave.1.35).They display seawater signatures with reduced oxygen conditions.The enrichment in RSE(Mo,Cu,Ni,and Zn)and the low Mo/TOC(0.70-3.69;ave.2.41)support a certain degree of water restriction.The high Sr/Ba,Sr/Cu,Ga/Rb,and K/Al records of the LBL facies suggest hot house climatic conditions.The sedimentary environment was probably an isolated basin that is transformed from the marine basin.In addition to depositional conditions,the regional parameters such as the climate,increased run-off period,nutrient levels,alkalinity level,and dominant carbonate producers favored the enrichment in organic matter of LBL facies.Thus,extreme greenhouse palaeoclimate conditions have an important role in organic matter enrichment in the isolated basin.Our results are conformable with the published data from marine,semi-restricted basin,and lacustrine settings in the different parts of the Tethys margin.Thus,this approach provides the first insight into the Aptian greenhouse paleo-climate conditions of the Eastern Black Sea Region,NE Turkey.

Nitrate isotope dynamics in the lower euphotic-upper mesopelagic zones of the western South China Sea

The dual isotopes(N and O)of nitrate were measured using a denitrifier bacterial method in the western South China Sea(WSCS)during September 2015 to elucidate key information during N transformation in the lower euphotic zone(LEZ)-upper mesopelagic zone(UMZ,down to 500 m in this study)continuum,which is a vital sub-environment for marine N cycle and sequestration of atmospheric CO_(2)as well.The N isotopic composition(δ^(15)N)of nitrate generally decreased from 500 m toward the base of the euphotic zone(∼100 m),reaching a value of∼4.6‰(vs.air N_(2))at the base of the LEZ,suggesting the imprint of remineralization(nitrification)of isotopically light N from atmospheric source.Theδ^(15)N andδ18O of nitrate only generally conform to a 1:1 line at 50 m and 75 m,suggesting that nitrate assimilation is a dominant process to shape nitrate isotope signature in this light-limited and relatively N-replete lower part of the euphotic zone.The fractionation factors of N and O isotopes during nitrate fractionation(15εASSIM,18εASSIM)using a steady-state model were estimated to be 4.0‰±0.3‰and 5.4‰±0.3‰,respectively.The occurrence of nitrification at the base of the LEZ and most of the UMZ is corroborated by the decoupling ofδ^(15)N and the oxygen isotopic composition(δ18O)of nitrate.Our results will provide insights for better understanding N cycle in the South China Sea from a perspective of present and past.

Power-law patterns in the Phanerozoic sedimentary records of carbon, oxygen, sulfur,and strontium isotopes

Power-law patterns appear in a variety of natural systems on the modern Earth;nevertheless,whether such behaviors appeared in the deep-time environment has rarely been studied. Isotopic records in sedimentary rocks, which are widely used to reconstruct the geological/geochemical conditions in paleoenvironments and the evolutionary trajectories of biogeochemical cycles, offer an opportunity to investigate power laws in ancient geological systems. In this study, I focus on the Phanerozoic sedimentary records of carbon, oxygen, sulfur, and strontium isotopes, which have well documented and extraordinarily comprehensive datasets. I perform statistical analyses on these datasets and show that the variations in the sedimentary records of the four isotopes exhibit power-law behaviors. The exponents of these power laws range between 2.2 and 2.9;this narrow interval indicates that the variations in carbon, oxygen, sulfur, and strontium isotopes likely belong to the same universality class, suggesting that these systematic power-law patterns are governed by universal, scale-free mechanisms. I then derive a general form for these power laws from a minimalistic model based on basic physical principles and geosystem-specific assumptions, which provides an interpretation for the power-law patterns from the perspective of thermodynamics. The fundamental mechanisms regulating such patterns might have been ubiquitous in paleoenvironments, implying that similar power-law behaviors may exist in the sedimentary records of other isotopes.

Phosphorite generative processes around the Precambrian-Cambrian boundary in South China: An integrated study of Mo and phosphate O isotopic compositions

Large phosphorite deposits in Central Guizhou,China,were formed around the Precambrian/Cambrian boundary(PC/C),including the Ediacaran(Doushantuo stage)and early Cambrian(Gezhongwu stage).Among them,Gezhongwu phosphorite from Zhijin are enriched in rare earth elements(REE)plus yttrium(REY),reaching 3.503 million tons.Although phosphorites have attracted great attention,the specific sources P and REY remained unclear.To determine the P and REY sources and establish a phosphogenic model of PC/C phosphorite,we present an integrated dataset of Mo and phosphate O isotopes for the first time,along with carbonate C and O isotopes,geology,petrology,and geochemistry.In all samples,d18Op,Y/Ho,and Zr/Hf decreased from the Ediacaran to the early Cambrian,indicating increased terrigenous weathering fluxes while decreased upwelling water input.Furthermore,terrigenous weathering delivery significantly elevated marine REY concentrations in the Cambrian in Zhijin.The Ceanom and d98/95Mo suggest that seawater was oxidized in the later Ediacaran and became entirely oxic in the early Cambrian.The positive feedback between oxygen levels in atmosphere and primary productivity caused progressive oxygenation in ocean-atmosphere system and enable phosphorites to be formed by different mechanisms.Results show that the Lower Doushantuo consist of abiotic intraclasts and exhibited“seawaterlike”REY types,indicating abiological and mechanical reworking phosphogenesis.The Upper Doushantuo and Gezhongwu Formation contained mainly microbial debris and abiogenic intraclasts,and exhibit “hat-shaped”REY plots,suggesting microbially mediated phosphogenesis.Based on this data set,we developed a phosphogenic model illustrating formation of these two phosphorite deposits,wherein the Lower Doushantuo phosphorite formed through the reworking of pre-existing phosphatic sediments in anoxic and abiotic ocean,whereas the Upper Doushantuo and Gezhongwu phosphorite formed via microbial metabolisms in oxic and biotic conditions.Our study has implications on the PC/C phosphorite generative processes,as well as paleoenvironmental conditions.

The giant tin polymetallic mineralization in southwest China:Integrated geochemical and isotopic constraints and implications for Cretaceous tectonomagmatic event

The Gejiu-Bozushan-Laojunshan W-Sn polymetallic metallogenic belt(GBLB)in southeast Yunnan Province is an important part of the southwestern Yangtze Block in South China.Tin polymetallic mineralization in this belt includes the Niusipo,Malage,Songshujiao,Laochang and Kafang ore fields in the Gejiu area which are spatially and temporally associated with the Kafang-Laochang and Songshujiao granite plutons.These granites are characterized by variable A/CNK values(mostly>1.1,except for two samples with 1.09),high contents of SiO2(74.38-76.84 wt.%)and Al2 O3(12.46-14.05 wt.%)and variable CaO/Na2 O ratios(0.2-0.65)as well as high zirconδ18O values(7.74‰-9.86‰),indicative of S-type affinities.These rocks are depleted in Rb,Th,U,Ti,LREE[(La/Yb)N=1.4-20.51],Ba,Nb,Sr,and Ti and display strong negative Eu and Ba anomalies.The rocks possess high Rb/Sr and Rb/Ba ratios,relatively low initial 87Sr/86Sr ratios(0.6917-0.7101),and less radiogenicεNd(t)values(-8.0 to-9.1).The zircon grains from these rocks show negativeεHf(t)values in the range of-3.7 to-9.9 with mean TDM2(Nd)and TDM2(Hf)values of 1.57 Ga and 1.55 Ga.They show initial 207Pb/204Pb ranging from15.69 to 15.71 and 206Pb/204Pb from 18.36 to 18.70.Monazite from Songshujiao granites exhibits higher U and lower Th/U ratios,lowerδ18O values and higherεHf(t)values than those of the zircon grains in the KafangLaochang granites.The geochemical and isotopic features indicate that the Laochang-Kafang granites originated by partial melting of Mesoproterozoic crustal components including biotite-rich metapelite and metagraywacke,whereas the Songshujiao granites were derived from Mesoproterozoic muscovite-rich metapelite crustal source.Most zircon grains from the Songshujiao,Laochang and Kafang granites have high-U concentrations and their SIMS U-Pb ages show age scatter from 81.6 Ma to 88.6 Ma,80.7 Ma to 86.1 Ma and 82.3 Ma to 87.0 Ma,suggesting formation earlier than the monazite and cassiterite.Monazite SIMS U-Pb ages and Th-Pb ages of three same granite samples are consistent and show yielded 206 Pb/238U ages of 83.7±0.6 Ma,83.7±0.6 Ma,and 83.4±0.6 Ma,and 208Pb/232Th ages of 83.2±0.5 Ma,83.8±0.4 Ma,and 83.5±0.9 Ma,which are within the range of the SIMS zircon U-Pb ages from these rocks.The data constrain the crystallization of the granites at ca.83 Ma.In situ U-Pb dating of two cassiterite samples from the cassiterite-sulfide ore in the Songshujiao ore field and Kafang ore field,and two from the cassiterite-oxide+cassiterite bearing dolomite in the Laochang ore field yielded weighted mean 206 Pb/238U ages of 83.5±0.4 Ma(MSWD=0.6),83.5±0.4 Ma(MSWD=0.5),83.6±0.4 Ma(MSWD=0.6)and 83.2±0.7 Ma(MSWD=0.6),respectively.Combined with geological characteristics,the new geochronological data indicate that the formation of the granites and Sn polymetallic deposits are coeval.We correlate the magmatic and metallogenic event with lithospheric thinning and asthenosphere upwelling in continental extension setting in relation to the eastward subduction of the Neo-Tethys beneath the Sanjiang tectonic domain during Late Cretaceous.

Lithological and Si–O–S isotope geochemistry:constraints on the origin and genetic environment of the selenium(Se)-rich siliceous rocks in Enshi,Hubei Province,China

Se-rich black rock series of the Middle and Late Permian system is widely distributed in Enshi Prefecture with an exposed area of 850 km~2,among which the unique Yutangba black rock series independent selenium deposit with industrial mining significance in the world is produced.However,the source and metallogenic mechanisms of Se are still controversial.In general,terrestrial weathering and submarine hydrothermal processes are the main source end members of Si and Se,and the related siliceous rocks record the deposition process of Si and Se from different sources.The study of lithofacies and paleogeography shows that western Hubei belongs to the near eastwest turn of the Yangzi platform in the Middle and Late Permian and becomes an inter-platform basin with nearly north-south direction.Therefore,the comparative study of the Yutangba deposit and the selenium-rich black rock series in the northern Shadi with high selenium content is expected to reveal the provenance evolution of the two sections in space,and further restrict the Se mineralization mechanism in the Enshi basin.From the element geochemistry study,the black rock series in two study areas may have formed in a transitional position of either the continental margin or continental slope,in the process of sedimentary,more terrigenous clastic materials entered.They are rich in lithophile elements V and Cr.δU>1.0,U/Th and V/(V+Ni)ratio indicate that the Se-rich strata of black rock series in the Enshi areas occurred in an anoxic reducing environment and formed in an environment between the ocean basin and the continental margin.From Si-O isotope geochemistry,the original Si source of the study area is thought to relate to a volcanic eruption,which leads to the enrichment of Si in the seawater.The determined values of S isotope in the black rock series of the two study areas both show the characteristics related to organic reduction/biogenic.

Use of δ^(18)O, δ^(13)C and NO_(3)^(-) to identify hydrogeochemical processes related to contamination in an aquifer located in central Mexico

In this work,an isotopic analysis of δ^(18)O,δ^(13)C,and NO_(3)^(-) concentrations was carried out to identify the origin and the processes related to the contamination of an aquifer located in the state of Guanajuato,Mexico.The research identified the possible sources of δ^(13)C in groundwater.During groundwater flow,CO_(2) participates in different hydrogeochemical reactions in which the dissolution of carbonates or biochemical processes related to biodegradation stand out.Isotopic data of δ^(13)C,δ^(18)O,and the hydrogeochemical behavior of NO_(3)^(-) and HCO_(3)^(-) in water,in addition to isotopic data and the chemical composition of limestones in the study area,were determined to establish the isotopic signature and the processes undergone by the rocks.The isotopic signature of rock and water samples indicated that metamorphic limestones contributed with carbon dioxide to deep groundwater,while in the upper aquifer,bacterial metabolic reactions during nitrification–denitrification could modify the isotopic signature of δ^(13)C in some wells,although atmospheric contribution also plays a role.The modification of the carbon isotopic component is related to the precipitation of calcite in specific regions of the study area,input of atmospheric CO_(2),and soil(e.g.the possible participation of C4-type plants in the assimilation-release of carbon).This process is not confirmed or completely ruled out in this study since agriculture is excessively developed throughout the region.The joint interpretation of isotopic values and the hydrogeochemical behavior of major and conservative elements help in identifying possible pollution processes in which different carbon sources are related.

Fluid effect on zircon O and U-Pb isotopes during ultrahigh-pressure metamorphism:Insights from the Dora-Maira Massif of the Western Alps

Zircon geochemistry such as U-Pb and O isotopes have been widely used in dating and tracing complex geological processes.However,it still remains unclear how fluid action affects zircon geochemistry during metamorphic and metasomatic processes in subduction zones.Here a systematic study on zircon U-Pb dating,O isotopes and trace elements as well as whole-rock O isotopes was carried out for the coesite-bearing whiteschists,jadeite quartzites and granitic gneisses from the Dora-Maira Massif,Western Alps.Whole-rock and zircon geochemistry supports a common protolith,i.e.,Permian S-type granites,for the above three types of rocks and an intense fluid metasomatism during the Alpine orogeny to form whiteschists and jadeite quartzites.Zircon cores in all samples have nearly identicalδ^(18)O values(9‰–11‰),whereas their apparent^(206)Pb/^(238)U ages show a greater variability due to Pb loss during metamorphism.Zircon rims formed in the late Eocene to early Oligocene can be categorized into two types.Type-Ⅰrims occur in granitic gneisses and jadeite quartzites.They have highδ^(18)O values consistent with zircon cores,but much lower contents of P and Y as well as lower Th/U ratios than the cores.Their growth can be attributed to internal metamorphic fluid action at the UHP metamorphic stage.Type-II rims occur in whiteschists and jadeite quartzites.They have remarkably lowerδ^(18)O values(5‰–8‰)and Th/U ratios(<0.01),compared with zircon cores and Type-Ⅰrims.Their growth can be ascribed to external fluids during the metasomatic process.Some zircon domains in whiteschists and jadeite quartzites show a positive correlation betweenδ^(18)O values and apparent^(206)Pb/^(238)U ages,which suggest the simultaneous impacts on U-Pb-O isotopes during external fluid metasomatism.This process can be attributed to the fluidassisted dissolution and recrystallization of protolith zircons.Especially,coesite inclusions that would have been expected to occur only in young zircon rims formed during UHP metamorphism are also observed in the relict magmatic zircon cores,indicating that the fluid-related metasomatism at the UHP metamorphic conditions also affected these pre-existing protolith-related cores.Therefore,fluid action in subduction zones reveals significant impacts on both the U-Pb and O isotope systems of zircon,especially when external metasomatic fluids are involved.Therefore,a detailed study on zircon,including microstructure,mineral inclusion and geochemical data of different growth and recrystallization domains,is needed in order to unravel continental crustal evolution based on zircon U-Pb ages and O isotope compositions.

A review of^(17)O isotopic labeling techniques for solid-state NMR structural studies of metal oxides in lithium-ion batteries

Recent advances in utilizing^(17)O isotopic labeling methods for solid-state nuclear magnetic resonance(NMR)investigations of metal oxides for lithium-ion batteries have yielded extensive insights into their structural and dynamic details.Herein,we commence with a brief introduction to recent research on lithium-ion battery oxide materials studied using^(17)O solid-state NMR spectroscopy.Then we delve into a review of^(17)O isotopic labeling methods for tagging oxygen sites in both the bulk and surfaces of metal oxides.At last,the unresolved problems and the future research directions for advancing the^(17)O labeling technique are discussed.

Decoupling between Oxygen and Radiogenic Isotopes: Evidence for Generation of Juvenile Continental Crust by Partial Melting of Subducted Oceanic Crust

There is increasing evidence indicating that melts derived from subducted oceanic crust and sediments may have played a key role in building continental crust. This mechanism predicts that juvenile arc crust should have oxygen isotope characteristics ranging from mantle-like to supracrustal, but consistent mantle-like radiogenic(Nd-Hf) isotopic signatures. Here we present in-situ zircon U-Pb dating, Hf-O isotope analyses, and whole rock major-trace element and Nd isotope analyses of a granitoid from NW India. In-situ secondary ion mass spectrometry(SIMS) zircon U-Pb dating yields a weighted mean ^(207)Pb/^(206)Pb age of 873±6 Ma for the granitoid. It displays mantle-like zircon εHf(εHf(873 Ma)= +9.3 to +10.9) and whole-rock Nd(εNd(873 Ma)= +3.5) values but supracrustal δ^(18)O values, the latter mostly varying between 9‰ and 10‰. The calculated whole-rock δ^(18)O value of 11.3‰±0.6‰ matches well with those of hydrothermally-altered pillow lavas and sheeted dykes from ophiolites. The major and trace element composition of the granitoid is similar to petrological experimental melts derived from a mixture of MORB+sediments. Thus, the granitoid most likely represents the product of partial melting of the uppermost oceanic crust(MORB+sediments). We propose that the decoupling between Hf-Nd and O isotopes as observed in this granitoid can be used as a powerful tool for the identification of slab melting contributing to juvenile continental crustal growth. Such isotopic decoupling can also account for high δ^(18)O values observed in ancient juvenile continental crust, such as Archean tonalitetrondhjemite-granodiorite suites.

Geochemistry and in-situ U-Th/Pb Geochronology of the Jambil Meta-Carbonatites, Northern Pakistan: Implications on Petrogenesis and Tectonic Evolution

The putative Jambil meta-carbonatites of Swat,northern Pakistan,occur as discrete intrusions into the Proterozoic Manglaur Formation,which are difficult to be distinguished from nearby calc-silicate marble because both rock types experienced regional metamorphism during Himalayan orogenesis that resulted in similar mosaic textures and mineral assemblages.Carbonatites are often significant repositories of economic mineral resources and,therefore,are important to be distinguished from calc-silicate marble.We present new geochemical and geochronology data to distinguish between the two rock types and interpret the petrogenesis and tectonic evolution of the Jambil metacarbonatites.Whole rock chemical data from the Jambil meta-carbonatites show characteristically high rare earth element(REE),Sr contents and lack of negative Eu anomaly,consistent with average calcio-carbonatite values worldwide and an igneous origin.More than 0.5 wt.% SrO in the metacarbonatites and SrO> 0.15 wt.% in constituent rock forming calcite are discriminating signatures of the Jambil meta-carbonatites.Chemically,the Jambil meta-carbonatites are relatively depleted in Rb,Nb,Ta,Ti,Zr and Hf,relatively enriched in Ba,Th,Sr,and have a high LREE/HREE ratio when normalized to primitive mantle.Their carbon and oxygen isotope compositions vary from-3.5‰ to-4.3‰and from 9.7‰ to 12.3‰,respectively.These geochemical characteristics indicate generation of the carbonatites through small degree of partial melting from a carbonated eclogitic source.In-situ,U/Pb analysis of titanite indicates that the Jambil meta-carbonatites were emplacement at 438 ±3 Ma.When combined with regional geological observations,we interpret the emplacement of the Jambil metacarbonatites to have taken place during the Silurian back arc extension within greater Gondwana and mark a transition from a compressional tectonic regime,brought about by collision of microcontinental blocks along the northern margin of Gondwana,to post-orogenic extension in the waning stages of the pre-Himalayan Ordovician orogeny.Finally,in-situ ^(208)Pb/^(232)Th monazite dates(40.3-27.6Ma) extracted from the meta-carbonatites are consistent with the Cenozoic metamorphism of the area.

Single-cell Raman and functional gene analyses reveal microbial P solubilization in agriculture waste-modified soils

Application of agricultural waste such as rapeseed meal(RM)is regarded as a sustainable way to improve soil phosphorus(P)availability by direct nutrient supply and stimulation of native phosphate‐solubilizing microorganisms(PSMs)in soils.However,exploration of the in situ microbial P solubilizing function in soils remains a challenge.Here,by applying both phenotype‐based single‐cell Raman with D_(2)O labeling(Raman‐D_(2)O)and genotype‐based high‐throughput chips targeting carbon,nitrogen and P(CNP)functional genes,the effect of RM application on microbial P solubilization in three typical farmland soils was investigated.The abundances of PSMs increased in two alkaline soils after RM application identified by single‐cell Raman D_(2)O.RM application reduced the diversity of bacterial communities and increased the abundance of a few bacteria with reported P solubilization function.Genotypic analysis indicated that RM addition generally increased the relative abundance of CNP functional genes.A correlation analysis of the abundance of active PSMs with the abundance of soil microbes or functional genes was carried out to decipher the linkage between the phenotype and genotype of PSMs.Myxococcota and C degradation genes were found to potentially contribute to the enhanced microbial P release following RM application.This work provides important new insights into the in situ function of soil PSMs.It will lead to better harnessing of agricultural waste to mobilize soil legacy P and mitigate the P crisis.

Sm-Nd Geochronology,REE and C and O Isotope Study of Calcites and Stibnites from Banian Antimony Deposit

The Banian sediment-hosted antimony deposit is a medium-scale deposit located in the Dushan County,South Guizhou,China.Calcite as the dominant gangue mineral can be divided into two types: white and pink,the later is more intimate with mineralization.It is interesting that the REE characteristics are

Nuclear chart in covariant density functional theory with dynamic correlations: From oxygen to tin

Nuclear masses of even-even nuclei with the proton number 8≤Z≤50(O to Sn isotopes)from the proton drip line to neutron drip line are investigated using the triaxial relativistic Hartree-Bogoliubov theory with the relativistic density functional PC-PK1.Further,the dynamical correlation energies(DCEs)associated with the rotational motion and quadrupole-shaped vibrational motion are taken into account by the five-dimensional collective Hamiltonian(5DCH)method.The root-mean-square deviation with respect to the experimental masses reduces from 2.50 to 1.59 MeV after the consideration of DCEs.The inclusion of DCEs has little influence on the position of drip lines,and the predicted numbers of bound even-even nuclei between proton and neutron drip lines from O to Sn isotopes are 569 and 564 with and without DCEs,respectively.