To explore the occurrence phases and enrichment mechanism of rare earth elements(REEs)in cobalt-rich crusts,this study analyzes the mineral composition and REE contents of the samples from Marcus-Wake Seamounts by XRD...To explore the occurrence phases and enrichment mechanism of rare earth elements(REEs)in cobalt-rich crusts,this study analyzes the mineral composition and REE contents of the samples from Marcus-Wake Seamounts by XRD,ICP-OES and ICP-MS.The results show that,(1)the cobalt-rich crusts contain the major crystalline mineral(vernadite),the secondary minerals(quartz,plagioclase and carbonate fluorapatite),and a large amount of amorphous ferric oxyhydroxides(FeOOH).(2)The cobalt-rich crusts contains higher Mn(10.83%to 28.76%)and Fe(6.14%to 18.86%)relative to other elements,and are enriched in REEs,with total REE contents of 1563−3238μg/g and Ce contents of 790−1722μg/g.Rare earth element contents of the old crusts are higher than those of the new crusts.Moreover,the non-phosphatized crusts have positive Ce and negative Y anomalies,and yet the phosphatized crusts have positive Ce and positive Y anomalies,indicating that cobalt-rich crusts is hydrogenetic and REEs mainly come from seawater.(3)Analytical data also show that the occurrence phases of elements in cobalt-rich crusts are closely related to their mineral phases.In the non-phosphatized crusts,REEs are adsorbed by colloidal particles into the crusts(about 67%of REEs in the Fe oxide phase,and about 17%of REEs in the Mn oxide phase).In contrast,in the phosphatized crusts(affected by the phosphatization),REEs may combine with phosphate to form rare earth phosphate minerals,and about 64%of REEs are enriched in the residual phase containing carbonate fluorapatite,but correspondingly the influence of Fe and Mn oxide phases on REEs enrichment is greatly reduced.In addition,the oxidizing environment of seawater,high marine productivity,phosphatization,and slow growth rate can promote the REE enrichment.This study provides a reference for the metallogenesis of cobalt-rich crusts in the Pacific.展开更多
A biostratigraphic study on calcareous nannofossils from the CM3D06 Co-rich ferromanganese crust from the Magellan seamounts in the northwestern Pacific enabled estimation of depositional age. The bio-imprinting of ca...A biostratigraphic study on calcareous nannofossils from the CM3D06 Co-rich ferromanganese crust from the Magellan seamounts in the northwestern Pacific enabled estimation of depositional age. The bio-imprinting of calcareous nannofossils and other fossil species suggests six age ranges for the nannofossils: late Cretaceous, late Paleocene, (early, middle, late) Eocene, middle Miocene, late Pliocene, and Pleistocene. Gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) were used to test the Co-rich crusts, and a variety of molecular fossils were detected, such as chloroform bituminous "A" , n-alkane, isoprenoid and sterol. Peak carbon and molecular indices (such as C23-/C24+, CPI, Pr/Ph, Pr/nC17, Ph/nCxs and j13C) indicate that the parent organic matter is dominated by marine phytoplankton and thallogen whereas there is little input of terrestrial organic matter. Researches on calcareous nannofossils, molecular fossils and molecular organic geochemistry data reveal that the Paleocene/Eocene (P/E) global event is recorded in the cobalt- rich crusts from the northwestern Pacific Ocean. A succession of biomes can be observed near the 85 mm boundary (about 55 Ma), i.e., the disappearance of the late Cretaceous Watznaueria barnesae and Zigodicus spiralis, and Broisonia parka microbiotas above the P/E boundary, and the bloom of Coccolithus formosus, Discoaster multiradiatus, Discoaster mohleri and Discoaster sp. below the boundary. Typical parameters of molecular fossils, such as saturated hydrocarbon components and carbon-number maxima, Pr/Ph, Pr/C17, Ph/C18, distribution types of sterols, Ts/Tm ratios and bacterial hopane, also exhibit dramatic changes near the P/E boundary. These integrated results illustrate that the biome succession of calcareous nannofossils, relative content of molecular fossils and molecular indices in the cobalt-rich crusts near the 85 mm boundary faithfully record the P/E global event.展开更多
Organic matter in cobalt-rich crust (CRC) from the Marcus-Wake Seamounts of the western Pacific Ocean, Sample CM1D03, has been analyzed to understand the source, geochemistry and mineralization of organic matter, an...Organic matter in cobalt-rich crust (CRC) from the Marcus-Wake Seamounts of the western Pacific Ocean, Sample CM1D03, has been analyzed to understand the source, geochemistry and mineralization of organic matter, and the mineralization environment. Biomarkers, includingn-alkanes, isoprenoids, terpanes and sterols, have been detected in various layers of the CRC sample, using gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The content of organic carbon (OC) and its stable isotope (δ13C), and the combined features of the biomarkers show that the mineralized organic matter in CM1D03 CRC was mainly derived from microorganisms and lower plankton (e.g., bacteria and algae, respectively) from marine surface water, with some terrestrial higher plant components. The ratio of chloroform bitu-men "A": OC was high in the CRC, between 10.51 and 20.66, showing significant migration characteristics of n-alkanes. Four mineralization categories of organic matter were recognized based on GC chromatograms ofn-alkane molecules: (1) primitive type (bacteria and algae), which is characterized by moderately mature ofn-alkanes preserving the original characteristics of the organic matter from microorganisms and lower plankton; (2) microbial degradation type, which is characterized by low contents ofn-alkanes and rising baseline in the chromatogram, with the "bulge" being the products of organic matter by biodegradation; (3) organic matter migration type, which is characterized by low carbon number ofn-alkanes withnC18 as the main peak carbon, without odd even predominance, and low concentrations of isoprenoids and hydro-carbons with high carbon number; and (4) organic matter hydrothermal type, which is characterized by relatively low concentration of small molecular weightn-alkanes, pristane, and phytane, accompanied by higher concentration ofn-alkanes with carbon number greater thannC18. This study shows that biomarkers can record controlling factors of mineralization and their variation.展开更多
Rare earth elements(REEs) and major elements of 25 cobalt-rich crusts obtained from different depths of Mid-Pacific M seamount were analyzed using inductively coupled plasma-atomic emission spectrometer and gravimet...Rare earth elements(REEs) and major elements of 25 cobalt-rich crusts obtained from different depths of Mid-Pacific M seamount were analyzed using inductively coupled plasma-atomic emission spectrometer and gravimetric method.The results showed that they were hydrogenous crusts with average ∑REE content of 2084.69 μg/g and the light REE(LREE)/heavy REE(HREE) ratio of 4.84.The shale-normalized REE patterns showed positive Ce anomalies.The total content of strictly trivalent REEs increased with water depth.The Ce content and LREE/HREE ratios in Fe-Mn crusts above 2000 m were lower than those below 2000 m.The change in REE with water depth could be explained by two processes:adsorptive scavenging by setting matters and behaviors of REE in seawater.However, the Ce abundance took no obvious correlation with water depth reflects the constant Ce flux.The Ce in crusts existed mainly as Ce(IV), implying that the oxidative-enriching process was controlled by kinetic factors.展开更多
Many seamounts are covered with cobalt-rich ferromanganese crusts,and are increasingly attracting interest for the potential extraction of valuable mineral resources from deep seabed environments.However,the impacts o...Many seamounts are covered with cobalt-rich ferromanganese crusts,and are increasingly attracting interest for the potential extraction of valuable mineral resources from deep seabed environments.However,the impacts of potential mining activities on the vulnerable seamount ecosystem remain unclear.To enhance the understanding of connectivity in benthic invertebrate populations in the Northwest Pacific,several seamounts were surveyed and biological samples collected.In the present study,the ophiuroid species Ophioplinthaca defensor is reported for the first time from four deep seamounts in the Northwest Pacific,and described,providing more detailed morphological diagnosis characters.To assess the population structure of the species between and within seamounts,two mitochondrial markers(COI and 16 S)were sequenced.In total,20 haplotypes from 32 COI sequences and 8 haplotypes from 3716 S sequences were recovered.The star-shaped TCS networks and nonsignificant pairwise population differences reveal the absence of distinct population structures between and within seamounts.In addition,the O.defensor population seemed to have undergone a demographic expansion in history.This is the first study on the genetic population structure of a benthic invertebrate from seamounts in the Northwest Pacific,and this results suggest a potentially high,long distance dispersal capacity in O.defensor between seamounts,which could inform the development of the Regional Environmental Management Plans for the cobalt-rich crust seamounts in the area.展开更多
On the basis of three geological models and several orebody boundaries, a method of grid subdivision and integral has been proposed to calculate and evaluate the resources of cobalt-rich crusts on the seamounts in the...On the basis of three geological models and several orebody boundaries, a method of grid subdivision and integral has been proposed to calculate and evaluate the resources of cobalt-rich crusts on the seamounts in the central Pacific Ocean. The formulas of this method are deduced and the interface of program module is designed. The method is carried out in the software "Auto mapping system of submarine topography and geomorphology MBChart". This method and program will possibly become a potential tool to calculate the resources of seamounts and determine the target diggings for China' s next Five-year Plan.展开更多
It is a great concern in international oceanology to mine cobalt-rich crust. At present, spiral mining head is regarded as the best crushing scheme. Based on the dynamic model of spiral mining head, the of cobalt crus...It is a great concern in international oceanology to mine cobalt-rich crust. At present, spiral mining head is regarded as the best crushing scheme. Based on the dynamic model of spiral mining head, the of cobalt crust’s crushing process was simulated with the ANSYS software. The material model of Johnson and Cook Plasticity, maximal princi- pal stress failure criterion, and eroding contact arithmetic were selected. At the same time, the influence of cutting depth, feed speed, rotational speed of mining head on torque and force subjected by mining head was taken into account. At last a computer simulation model of crushing process of cobalt crust was established. By analyzing simulation results, the relationships among these controllable process parameters, torque and force can be obtained, which will provide a technical reference for practical mining system.展开更多
Based on the on the spot investigation and related data, cobalt rich crust is mainly distributed in the low latitude area near the equator, mostly within 20°S to 20°N, especially 5°-15°(S and N). ...Based on the on the spot investigation and related data, cobalt rich crust is mainly distributed in the low latitude area near the equator, mostly within 20°S to 20°N, especially 5°-15°(S and N). The analysis of the microtopographic and microphysicognomy features shows that crusts are often present in the complicated topographic regions such as seamount slopes, convex parts of seamounts and joint faults, of which the ideal region is seamount slopes in water depth of 1 500-2 500 m. The authors analyze the relation of the crusts and their bedrock, bedrock type, crust thickness and occurrence, and then attempt to classify the crusts as different types.展开更多
The Qinghai-Tibet Plateau is now experiencing ecological degradation risks as a result of climate change and human activities.The alpine grassland ecology in permafrost zones is fragile and susceptible to deterioratio...The Qinghai-Tibet Plateau is now experiencing ecological degradation risks as a result of climate change and human activities.The alpine grassland ecology in permafrost zones is fragile and susceptible to deterioration due to its high altitude,low temperature,and limited oxygen,which complicates the repair of damaged land.Biological soil crusts(BSCs)are crucial for land restoration in plateau regions because they can thrive in harsh conditions and have environmentally beneficial traits.Inoculated biological soil crust(IBSC)has shown success in low-altitude desert regions,but may not be easily duplicated to the plateau environment.Therefore,it is essential to do a comprehensive and multifaceted analysis of the basic theoretical comprehension and practical application of BSCs on the Tibetan Plateau.This review article aims to provide a brief summary of the ecological significance and the mechanisms related to the creation,growth,and progression of BSCs.It discusses the techniques used for cultivating BSCs in laboratories and using them in the field,focusing on the Qinghai-Tibet Plateau circumstance.We thoroughly discussed the potential and the required paths for further studies.This study may be used as a basis for selecting suitable microbial strains and accompanying supplemental actions for implementing IBSCs in the Qinghai-Tibet Plateau.展开更多
High-silica granitoids record the formation and evolution of the continental crust.A new intrusive complex has been recognized among silicic volcanic rocks of the Weixi arc,Southwest China.The intrusions consist of gr...High-silica granitoids record the formation and evolution of the continental crust.A new intrusive complex has been recognized among silicic volcanic rocks of the Weixi arc,Southwest China.The intrusions consist of granites,granitic porphyries,and granodiorites.Zircon U-Pb age data indicate that the Weixi granitoids formed at 248-240 Ma and were coeval with silicic volcanic rocks of the Weixi arc.The Weixi granitoids are enriched in Rb,Th,and U,depleted in Ba,Sr,Nb,Ta,and Ti,and have high light/heavy rare earth element ratios and slightly negative Eu anomalies.The Weixi granitoids have negative ε_(Nd)(t)values(-9.8 to-7.8)and negative zircon ε_(Hf)(t)values(-12.02 to-5.11).The geochemical and isotopic features suggest the Weixi granitoids were derived by partial melting of ancient crustal material.The Weixi granitoids and silicic volcanic rocks were derived from the same magma by crystal accumulation and melt extraction,respectively,and they record the formation of a continental arc in the central Sanjiang orogenic belt.展开更多
Collapsing erosion is a unique phenomenon commonly observed on the granite residue hillslopes in the tropical and subtropical regions of southern China,characterized by its abrupt occurrence and significant erosion vo...Collapsing erosion is a unique phenomenon commonly observed on the granite residue hillslopes in the tropical and subtropical regions of southern China,characterized by its abrupt occurrence and significant erosion volumes.However,the impacts of soil crust conditions on the erosion of colluvial deposits with granite residual soils have only been studied to a limited extent.To address this issue,this study investigates the impacts of three soil crust conditions(i.e.,without crust,10-minute crust,and 20-minute crust)on gully morphology,rainfall infiltration,and runoff and sediment yield during slope erosion of colluvial deposits with granite residues(classified as Acrisols)in Yudu County,Ganzhou City,Jiangxi Province,China,using simulated rainfall tests and photographic methods.The results showed that as the strength of the soil crust increased,the capacity of moisture infiltration and the width and depth of the gully as well as the sediment concentration and yield ratio decreased;at the same time,the runoff ratio increased.The sediment yield in the without-crust test was found to be 1.24 and 1.43 times higher than that observed in the 10-minute crust and 20-minute crust tests,respectively.These results indicate that soil crusts can effectively prevent slope erosion and moisture infiltration,while providing valuable insights for the management of soil erosion in natural environments.展开更多
Biological soil crusts(BSCs)play an important role in soil development and ecological function,and it is more important for quantitatively analyzing the processes and trends of BSCs to identify the advantages and disa...Biological soil crusts(BSCs)play an important role in soil development and ecological function,and it is more important for quantitatively analyzing the processes and trends of BSCs to identify the advantages and disadvantages of BSCs research for the development and application of BSCs theory.Bibliometric analysis of 2,186 BSCs literatures from Web of Science showed an exponential growth trend,as China and the United States as the top 2 in terms of publication volume.High quality publications are mainly from European and American countries,such as the United States,Germany and Spain.The top 3 publishers are Journal of Arid Environments,Soil Biology&Biochemistry and Plant and Soil,and disciplines include ecology,environmental science,and soil science,etc..Research institutions mainly affiliate to the Chinese Academy of Sciences,United States Department of the Interior,United States Geological Survey,Hebrew University of Jerusalem,Consejo Superior de Investigaciones Cientificas,and Universidad Rey Juan Carlos.Authors mainly come from United States,Israel,Spain and China.Funds are mainly from the National Natural Science Foundation of China,Spanish Government,Chinese Academy of Sciences,and National Science Foundation of the United States.Biological soil crusts(biocrusts,cyanobacteria,lichens,moss crusts,bryophytes),drylands,climate change,photosynthesis and desert are high-frequency keywords.Future research will focus on the driving mechanisms of BSCs on global biogeochemical cycles,maintaining global biodiversity on important ecological processes,global C,N,and P cycles.The impact on biological invasion,sandstorms,and water balance,multifunctional and reciprocal mechanisms for maintaining the stability of desert and sandy ecosystems,and impact on the formulation of management policies for arid ecosystems,corresponding to global climate change,and the estimation of regional,local,and microscale distribution of BSCs based on machine deep learning modeling gradually focus on.The ecosystem service functions of BSCs,the soil and water conservation and soil stability mediated by BSCs in arid and semi-arid regions,and the excavation of stress resistant genes for BSCs will be emphasized.展开更多
Two records of the crust laminae from the Marcus-Wake Seamounts and the Magellan Seamount were biostratigraphically studied. Based on biological imprints of the calcareous nannofossils, the geological ages of the two ...Two records of the crust laminae from the Marcus-Wake Seamounts and the Magellan Seamount were biostratigraphically studied. Based on biological imprints of the calcareous nannofossils, the geological ages of the two records were determined, with CM1D03 from the Marcus-Wake Seamounts being of late Paleocene to Pleistocene and CM3D06 from the Magellan Seamount of Late Cretaceous (more than 70.0 Ma). There are the obvious temporal-spatial differences in the initial formation period and enrichment characteristics of the cobalt-rich crusts of the two seamount chains and differences in the combination and distribution of microfossils in the inner crust layers between the seamounts. These differences are due to the adaptabilities of oceanic species in different environments. Ecological research was carried out in terms of population size of the calcareous nannofossi|s preserved in the crustal layers to discern the relation of the geological events at the Eocene-Oligocene (E/O) tran- sition. The results show the transitions and recombination of species in the biotic community during the E/O transition obvi- ously corresponded to 25 mm depth in the CM1D03 crust and 58 mm depth in the CM3D06 crust. The changes in biological species and the formation of particular ecological structures indicate the adaptive response of the paleo-biological community in the western Pacific Ocean to the global cold-climate events and the close correlation between the formation of the crust and the global climate change.展开更多
In 2001, the International Seabed Authority (ISBA) initiated the consideration relating to the Regulations for Prospecting and Exploration for Hydrothermal Polymetallic Sulphides and Cobalt-rich Ferromanganese Crust...In 2001, the International Seabed Authority (ISBA) initiated the consideration relating to the Regulations for Prospecting and Exploration for Hydrothermal Polymetallic Sulphides and Cobalt-rich Ferromanganese Crusts in the Area at its 7th session. Since then, the consideration of the Regulations has been mainly focused on the size of areas to be allocated for exploration and exploitation of the crusts. This paper, based on the investigation data and the analysis of the distribution characteristics of the crusts, suggests a model for determining the size of areas for exploration and exploitation of the crusts, taking into account various factors such as production scale, crust thickness and grade, mineable area proportion, recovery efficiency, exploration venture, and so on. Through the modeling, the paper suggests that the exploration area (the area covered by each application for approval of a plan of work for exploration of cobalt-rich crusts) shall be 4 856 km2 and the exploitation area (the mine site area) shall be 1 214 km2, for 20 years of 1 million wet tonnes annual production.展开更多
An ammonia leaching process was utilized to extract Co, Ni and Cu from oceanic polymetallic nodules, whereas an acid leaching process was utilized to extract Co, Ni, Cu, Zn and Mn from cobalt-rich crusts. Both process...An ammonia leaching process was utilized to extract Co, Ni and Cu from oceanic polymetallic nodules, whereas an acid leaching process was utilized to extract Co, Ni, Cu, Zn and Mn from cobalt-rich crusts. Both processes produced nanometer materials-ammonia leaching residue and acid leaching residue. A systematic study was conducted on the phase, composition and physicochemistry properties of these residues. The result shows that both residues contain a large amount of nanometer minerals. Ammonia leaching residue mainly consists of rhodochrosite, with the average grain diameter of 17.9 nm; whereas the acid leaching residue mainly consists of well-developed bassanite, with the average grain deameter of 9.5 nm. The bassanite also has a microporous structure, the volume of the pore space is 1.23×10-2 mL/g. Both the ammonia and acid leaching residues have a large specific surface area, and they display a strong adsorption capacity to saturate sodium chloride vapour, N2 and SO2. Both residues have high展开更多
Noble gas isotopic compositions of various layers in three-layered (outer, porous and compact layers) cobalt-rich ferromanganese crusts and their basaltic and phosphorite substrates from the western Pacific Ocean we...Noble gas isotopic compositions of various layers in three-layered (outer, porous and compact layers) cobalt-rich ferromanganese crusts and their basaltic and phosphorite substrates from the western Pacific Ocean were analyzed by using a high vacuum gas mass spectrum. The analytical results show that the noble gases in the Co-rich crusts have derived mainly from the ambient seawater, extraterrestrial grains such as interplanetary dust particles (IDPs) and wind-borne continental dust grains, and locally formation water in the submarine sediments, but different noble gases have different sources. He in the crusts derives predominantly from the extraterrestrial grains, with a negligible amount of radiogenic He from the eolian dust grains. Ar is sourced mainly from the dissolved air in the seawater and insignificantly from radiogenic Ar in the eolian continental dust grains or the formation water. Xe and Ne derive mainly from the seawater, with minor amounts of extraterrestrial Xe and Ne in the IDPs. Compared with the porous and outer layers, the compact layer has a relatively high 4He content and lower 3He/4He ratios, suggesting that marine phosphatization might have greatly modified the noble gas isotopic compositions of the crusts. Besides, the 3He/4He values of the basaltic substrates of the cobalt-rich crusts are very low and their R/R. ratios are mostly 〈0.1 R., which are similar to that of phosphorite substrates (0.087 R.), but much lower than that of fresh submarine MORB (8.75±14 Ra) or seamount basalts (3-43 Ra), implying that the basaltic substrates have suffered strong water/rock interaction and reacted with radiogenic ^4He and P-rich upwelling marine currents during phosphatization. The trace elements released in the basalt/seawater interaction might favor the growth of cobalt-rich crusts. The relatively low ^3He/^4He values in the seamount basalts may be used as an important exploration criterion for the cobalt-rich ferromanganese crusts.展开更多
Determining the upper boundary of the cobalt-rich crust distribution of a guyot is important for estimating the mineral resources available, however, it has also long been an unsolved question. Correlations between th...Determining the upper boundary of the cobalt-rich crust distribution of a guyot is important for estimating the mineral resources available, however, it has also long been an unsolved question. Correlations between the sub-bottom structures, revealed by sub-bottom profiling, and crust distribution can be revealed for the first time by the synchronous application of sub-bottom profiling and deep-sea video recording. The lower boundary of the sediment corresponds with the upper boundary of the crust. By analysis of these two kinds of data, the lower boundary of the sediment can be determined; therefore, the upper boundary of the crust distribution can be deduced. According to this method of analysis, the upper boundary of water depth of crust distribution of a seamount in the western Pacific is about 1 560 m.展开更多
A detailed study on a small scale of the effect of phosphatization on the chemistry of marine cobalt-rich ferromanganese crusts supplies useful information for the evaluation and comprehensive utilization of crust min...A detailed study on a small scale of the effect of phosphatization on the chemistry of marine cobalt-rich ferromanganese crusts supplies useful information for the evaluation and comprehensive utilization of crust mineral resources. Sub-samples from top to bottom of a 10-cm thick sample from the NW Pacific Magellan seamount were taken at 5 mm intervals. The concentration profiles of ore-forming and rare earth elements show that obvious differences exist between young unphosphatized crusts and old phosphatized crusts. In the old crusts Fe, Mn, Si, Al, Zn, Mg, Co, Ni and Cu elements are depleted and Ca, P, Sr, Ba and Pb elements are enriched. The order of depletion is Co > Ni > Mg > Al > Mn > Si> Cu > Zn > Fe, while the order of enrichment is P > Ca > Ba > Pb > Sr. The phosphate mineral controls the concentration variation of the ore-forming elements in crusts and causes loss of the main ore-forming elements such as Co and Ni. The phosphatization also affects the abundance of REEs in the crusts. REEs are more abundant and the content of Ce in old crusts is higher than that in young crusts, however, the pattern of REEs and their fractionation characteristics in new and old crusts are not fundamentally changed. A Y-positive anomaly in old crusts has no relationship to the phosphatization.展开更多
基金The fund of Laoshan Laboratory under contract Nos LSKJ202203602 and LSKJ202204103the China Ocean Mineral Resource Research and Development Association Research Program under contract No.DY135-C1-1-04the Taishan Scholarship from Shandong Province.
文摘To explore the occurrence phases and enrichment mechanism of rare earth elements(REEs)in cobalt-rich crusts,this study analyzes the mineral composition and REE contents of the samples from Marcus-Wake Seamounts by XRD,ICP-OES and ICP-MS.The results show that,(1)the cobalt-rich crusts contain the major crystalline mineral(vernadite),the secondary minerals(quartz,plagioclase and carbonate fluorapatite),and a large amount of amorphous ferric oxyhydroxides(FeOOH).(2)The cobalt-rich crusts contains higher Mn(10.83%to 28.76%)and Fe(6.14%to 18.86%)relative to other elements,and are enriched in REEs,with total REE contents of 1563−3238μg/g and Ce contents of 790−1722μg/g.Rare earth element contents of the old crusts are higher than those of the new crusts.Moreover,the non-phosphatized crusts have positive Ce and negative Y anomalies,and yet the phosphatized crusts have positive Ce and positive Y anomalies,indicating that cobalt-rich crusts is hydrogenetic and REEs mainly come from seawater.(3)Analytical data also show that the occurrence phases of elements in cobalt-rich crusts are closely related to their mineral phases.In the non-phosphatized crusts,REEs are adsorbed by colloidal particles into the crusts(about 67%of REEs in the Fe oxide phase,and about 17%of REEs in the Mn oxide phase).In contrast,in the phosphatized crusts(affected by the phosphatization),REEs may combine with phosphate to form rare earth phosphate minerals,and about 64%of REEs are enriched in the residual phase containing carbonate fluorapatite,but correspondingly the influence of Fe and Mn oxide phases on REEs enrichment is greatly reduced.In addition,the oxidizing environment of seawater,high marine productivity,phosphatization,and slow growth rate can promote the REE enrichment.This study provides a reference for the metallogenesis of cobalt-rich crusts in the Pacific.
基金supported by National Natural Science Foundation of China (Grant Nos. 41076072 and 40676025)
文摘A biostratigraphic study on calcareous nannofossils from the CM3D06 Co-rich ferromanganese crust from the Magellan seamounts in the northwestern Pacific enabled estimation of depositional age. The bio-imprinting of calcareous nannofossils and other fossil species suggests six age ranges for the nannofossils: late Cretaceous, late Paleocene, (early, middle, late) Eocene, middle Miocene, late Pliocene, and Pleistocene. Gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) were used to test the Co-rich crusts, and a variety of molecular fossils were detected, such as chloroform bituminous "A" , n-alkane, isoprenoid and sterol. Peak carbon and molecular indices (such as C23-/C24+, CPI, Pr/Ph, Pr/nC17, Ph/nCxs and j13C) indicate that the parent organic matter is dominated by marine phytoplankton and thallogen whereas there is little input of terrestrial organic matter. Researches on calcareous nannofossils, molecular fossils and molecular organic geochemistry data reveal that the Paleocene/Eocene (P/E) global event is recorded in the cobalt- rich crusts from the northwestern Pacific Ocean. A succession of biomes can be observed near the 85 mm boundary (about 55 Ma), i.e., the disappearance of the late Cretaceous Watznaueria barnesae and Zigodicus spiralis, and Broisonia parka microbiotas above the P/E boundary, and the bloom of Coccolithus formosus, Discoaster multiradiatus, Discoaster mohleri and Discoaster sp. below the boundary. Typical parameters of molecular fossils, such as saturated hydrocarbon components and carbon-number maxima, Pr/Ph, Pr/C17, Ph/C18, distribution types of sterols, Ts/Tm ratios and bacterial hopane, also exhibit dramatic changes near the P/E boundary. These integrated results illustrate that the biome succession of calcareous nannofossils, relative content of molecular fossils and molecular indices in the cobalt-rich crusts near the 85 mm boundary faithfully record the P/E global event.
基金The National Natural Science Foundation of China(NSFC)under contract Nos 41076072 and 40676025the Shandong Provincial Natural Science Foundation under contract No.ZR2011EMQ010
文摘Organic matter in cobalt-rich crust (CRC) from the Marcus-Wake Seamounts of the western Pacific Ocean, Sample CM1D03, has been analyzed to understand the source, geochemistry and mineralization of organic matter, and the mineralization environment. Biomarkers, includingn-alkanes, isoprenoids, terpanes and sterols, have been detected in various layers of the CRC sample, using gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The content of organic carbon (OC) and its stable isotope (δ13C), and the combined features of the biomarkers show that the mineralized organic matter in CM1D03 CRC was mainly derived from microorganisms and lower plankton (e.g., bacteria and algae, respectively) from marine surface water, with some terrestrial higher plant components. The ratio of chloroform bitu-men "A": OC was high in the CRC, between 10.51 and 20.66, showing significant migration characteristics of n-alkanes. Four mineralization categories of organic matter were recognized based on GC chromatograms ofn-alkane molecules: (1) primitive type (bacteria and algae), which is characterized by moderately mature ofn-alkanes preserving the original characteristics of the organic matter from microorganisms and lower plankton; (2) microbial degradation type, which is characterized by low contents ofn-alkanes and rising baseline in the chromatogram, with the "bulge" being the products of organic matter by biodegradation; (3) organic matter migration type, which is characterized by low carbon number ofn-alkanes withnC18 as the main peak carbon, without odd even predominance, and low concentrations of isoprenoids and hydro-carbons with high carbon number; and (4) organic matter hydrothermal type, which is characterized by relatively low concentration of small molecular weightn-alkanes, pristane, and phytane, accompanied by higher concentration ofn-alkanes with carbon number greater thannC18. This study shows that biomarkers can record controlling factors of mineralization and their variation.
基金supported by the National Natural Science Foundation of China(40704029 40376016)+1 种基金China International Science and Technology Cooperation Project (2006DFB21620)the Young People Marine Science Foundation of State Oceanic Administration (2005304)
文摘Rare earth elements(REEs) and major elements of 25 cobalt-rich crusts obtained from different depths of Mid-Pacific M seamount were analyzed using inductively coupled plasma-atomic emission spectrometer and gravimetric method.The results showed that they were hydrogenous crusts with average ∑REE content of 2084.69 μg/g and the light REE(LREE)/heavy REE(HREE) ratio of 4.84.The shale-normalized REE patterns showed positive Ce anomalies.The total content of strictly trivalent REEs increased with water depth.The Ce content and LREE/HREE ratios in Fe-Mn crusts above 2000 m were lower than those below 2000 m.The change in REE with water depth could be explained by two processes:adsorptive scavenging by setting matters and behaviors of REE in seawater.However, the Ce abundance took no obvious correlation with water depth reflects the constant Ce flux.The Ce in crusts existed mainly as Ce(IV), implying that the oxidative-enriching process was controlled by kinetic factors.
基金The National Natural Science Foundation of China under contract No.42076135the Foundation of China Ocean Mineral Resources R&D Association under contract Nos DY135-E2-2-06 and DY135-E2-2-03+1 种基金the Project of State Key Laboratory of Satellite Ocean Environment Dynamics,Second Institute of Oceanography,Ministry of Natural Resources,under contract No.SOEDZZ2002the Scientific Research Fund of the Second Institute of Oceanography,Ministry of Natural Resources,under contract No.JG1528
文摘Many seamounts are covered with cobalt-rich ferromanganese crusts,and are increasingly attracting interest for the potential extraction of valuable mineral resources from deep seabed environments.However,the impacts of potential mining activities on the vulnerable seamount ecosystem remain unclear.To enhance the understanding of connectivity in benthic invertebrate populations in the Northwest Pacific,several seamounts were surveyed and biological samples collected.In the present study,the ophiuroid species Ophioplinthaca defensor is reported for the first time from four deep seamounts in the Northwest Pacific,and described,providing more detailed morphological diagnosis characters.To assess the population structure of the species between and within seamounts,two mitochondrial markers(COI and 16 S)were sequenced.In total,20 haplotypes from 32 COI sequences and 8 haplotypes from 3716 S sequences were recovered.The star-shaped TCS networks and nonsignificant pairwise population differences reveal the absence of distinct population structures between and within seamounts.In addition,the O.defensor population seemed to have undergone a demographic expansion in history.This is the first study on the genetic population structure of a benthic invertebrate from seamounts in the Northwest Pacific,and this results suggest a potentially high,long distance dispersal capacity in O.defensor between seamounts,which could inform the development of the Regional Environmental Management Plans for the cobalt-rich crust seamounts in the area.
基金This study was supported by Projects under contract Nos DY105 China's 0cean-03-01-01 and DY105-03-01-07the National Natural Science Foundation of China under contract No.40506017the Youth Foundation of Marine High-tech Project of China under contract No.2002AA616010.
文摘On the basis of three geological models and several orebody boundaries, a method of grid subdivision and integral has been proposed to calculate and evaluate the resources of cobalt-rich crusts on the seamounts in the central Pacific Ocean. The formulas of this method are deduced and the interface of program module is designed. The method is carried out in the software "Auto mapping system of submarine topography and geomorphology MBChart". This method and program will possibly become a potential tool to calculate the resources of seamounts and determine the target diggings for China' s next Five-year Plan.
基金Project DY105-03-02-1 supported by COMRA project 50474052 supported by National Natural Science Foundation of China
文摘It is a great concern in international oceanology to mine cobalt-rich crust. At present, spiral mining head is regarded as the best crushing scheme. Based on the dynamic model of spiral mining head, the of cobalt crust’s crushing process was simulated with the ANSYS software. The material model of Johnson and Cook Plasticity, maximal princi- pal stress failure criterion, and eroding contact arithmetic were selected. At the same time, the influence of cutting depth, feed speed, rotational speed of mining head on torque and force subjected by mining head was taken into account. At last a computer simulation model of crushing process of cobalt crust was established. By analyzing simulation results, the relationships among these controllable process parameters, torque and force can be obtained, which will provide a technical reference for practical mining system.
文摘Based on the on the spot investigation and related data, cobalt rich crust is mainly distributed in the low latitude area near the equator, mostly within 20°S to 20°N, especially 5°-15°(S and N). The analysis of the microtopographic and microphysicognomy features shows that crusts are often present in the complicated topographic regions such as seamount slopes, convex parts of seamounts and joint faults, of which the ideal region is seamount slopes in water depth of 1 500-2 500 m. The authors analyze the relation of the crusts and their bedrock, bedrock type, crust thickness and occurrence, and then attempt to classify the crusts as different types.
基金funded by the National Key R&D Program of China (2022YFB4202102)the Key R&D Program of Ningxia Hui Autonomous Region (2022BEG02003)the Excellent Member of Youth Innovation Promotion Association CAS (No.Y202085)。
文摘The Qinghai-Tibet Plateau is now experiencing ecological degradation risks as a result of climate change and human activities.The alpine grassland ecology in permafrost zones is fragile and susceptible to deterioration due to its high altitude,low temperature,and limited oxygen,which complicates the repair of damaged land.Biological soil crusts(BSCs)are crucial for land restoration in plateau regions because they can thrive in harsh conditions and have environmentally beneficial traits.Inoculated biological soil crust(IBSC)has shown success in low-altitude desert regions,but may not be easily duplicated to the plateau environment.Therefore,it is essential to do a comprehensive and multifaceted analysis of the basic theoretical comprehension and practical application of BSCs on the Tibetan Plateau.This review article aims to provide a brief summary of the ecological significance and the mechanisms related to the creation,growth,and progression of BSCs.It discusses the techniques used for cultivating BSCs in laboratories and using them in the field,focusing on the Qinghai-Tibet Plateau circumstance.We thoroughly discussed the potential and the required paths for further studies.This study may be used as a basis for selecting suitable microbial strains and accompanying supplemental actions for implementing IBSCs in the Qinghai-Tibet Plateau.
基金financially supported by the State Key Research Development Program of China(Grant No.2022YFF0800903)the National Natural Science Foundation of China(NSFC)(Grant Nos.42261144669 and 42273073)。
文摘High-silica granitoids record the formation and evolution of the continental crust.A new intrusive complex has been recognized among silicic volcanic rocks of the Weixi arc,Southwest China.The intrusions consist of granites,granitic porphyries,and granodiorites.Zircon U-Pb age data indicate that the Weixi granitoids formed at 248-240 Ma and were coeval with silicic volcanic rocks of the Weixi arc.The Weixi granitoids are enriched in Rb,Th,and U,depleted in Ba,Sr,Nb,Ta,and Ti,and have high light/heavy rare earth element ratios and slightly negative Eu anomalies.The Weixi granitoids have negative ε_(Nd)(t)values(-9.8 to-7.8)and negative zircon ε_(Hf)(t)values(-12.02 to-5.11).The geochemical and isotopic features suggest the Weixi granitoids were derived by partial melting of ancient crustal material.The Weixi granitoids and silicic volcanic rocks were derived from the same magma by crystal accumulation and melt extraction,respectively,and they record the formation of a continental arc in the central Sanjiang orogenic belt.
基金This work was supported by the National Natural Science Foundation of China[Grant Nos.41962015,52208348]the Jiangxi Provincial Natural Science Foundation[Grant No.20224BAB214064,20232BAB204083].
文摘Collapsing erosion is a unique phenomenon commonly observed on the granite residue hillslopes in the tropical and subtropical regions of southern China,characterized by its abrupt occurrence and significant erosion volumes.However,the impacts of soil crust conditions on the erosion of colluvial deposits with granite residual soils have only been studied to a limited extent.To address this issue,this study investigates the impacts of three soil crust conditions(i.e.,without crust,10-minute crust,and 20-minute crust)on gully morphology,rainfall infiltration,and runoff and sediment yield during slope erosion of colluvial deposits with granite residues(classified as Acrisols)in Yudu County,Ganzhou City,Jiangxi Province,China,using simulated rainfall tests and photographic methods.The results showed that as the strength of the soil crust increased,the capacity of moisture infiltration and the width and depth of the gully as well as the sediment concentration and yield ratio decreased;at the same time,the runoff ratio increased.The sediment yield in the without-crust test was found to be 1.24 and 1.43 times higher than that observed in the 10-minute crust and 20-minute crust tests,respectively.These results indicate that soil crusts can effectively prevent slope erosion and moisture infiltration,while providing valuable insights for the management of soil erosion in natural environments.
基金supported by the National Natural Science Foundation of China(No.32260292,32060277)National Key Research and Development Program of China(No.2020YFC1522200)+2 种基金Shanxi Provincial Basic Research Program of China(No.202303021212060)Shanxi Provincial Cultural Relics Technology Program of China(No.2023KT15)The Local Project Guided by the Central Government of Gansu Province(No.YDZX20216200001728).
文摘Biological soil crusts(BSCs)play an important role in soil development and ecological function,and it is more important for quantitatively analyzing the processes and trends of BSCs to identify the advantages and disadvantages of BSCs research for the development and application of BSCs theory.Bibliometric analysis of 2,186 BSCs literatures from Web of Science showed an exponential growth trend,as China and the United States as the top 2 in terms of publication volume.High quality publications are mainly from European and American countries,such as the United States,Germany and Spain.The top 3 publishers are Journal of Arid Environments,Soil Biology&Biochemistry and Plant and Soil,and disciplines include ecology,environmental science,and soil science,etc..Research institutions mainly affiliate to the Chinese Academy of Sciences,United States Department of the Interior,United States Geological Survey,Hebrew University of Jerusalem,Consejo Superior de Investigaciones Cientificas,and Universidad Rey Juan Carlos.Authors mainly come from United States,Israel,Spain and China.Funds are mainly from the National Natural Science Foundation of China,Spanish Government,Chinese Academy of Sciences,and National Science Foundation of the United States.Biological soil crusts(biocrusts,cyanobacteria,lichens,moss crusts,bryophytes),drylands,climate change,photosynthesis and desert are high-frequency keywords.Future research will focus on the driving mechanisms of BSCs on global biogeochemical cycles,maintaining global biodiversity on important ecological processes,global C,N,and P cycles.The impact on biological invasion,sandstorms,and water balance,multifunctional and reciprocal mechanisms for maintaining the stability of desert and sandy ecosystems,and impact on the formulation of management policies for arid ecosystems,corresponding to global climate change,and the estimation of regional,local,and microscale distribution of BSCs based on machine deep learning modeling gradually focus on.The ecosystem service functions of BSCs,the soil and water conservation and soil stability mediated by BSCs in arid and semi-arid regions,and the excavation of stress resistant genes for BSCs will be emphasized.
基金supported by the National Natural Science Foundation of China(Grant Nos.41076072 and 40676025)
文摘Two records of the crust laminae from the Marcus-Wake Seamounts and the Magellan Seamount were biostratigraphically studied. Based on biological imprints of the calcareous nannofossils, the geological ages of the two records were determined, with CM1D03 from the Marcus-Wake Seamounts being of late Paleocene to Pleistocene and CM3D06 from the Magellan Seamount of Late Cretaceous (more than 70.0 Ma). There are the obvious temporal-spatial differences in the initial formation period and enrichment characteristics of the cobalt-rich crusts of the two seamount chains and differences in the combination and distribution of microfossils in the inner crust layers between the seamounts. These differences are due to the adaptabilities of oceanic species in different environments. Ecological research was carried out in terms of population size of the calcareous nannofossi|s preserved in the crustal layers to discern the relation of the geological events at the Eocene-Oligocene (E/O) tran- sition. The results show the transitions and recombination of species in the biotic community during the E/O transition obvi- ously corresponded to 25 mm depth in the CM1D03 crust and 58 mm depth in the CM3D06 crust. The changes in biological species and the formation of particular ecological structures indicate the adaptive response of the paleo-biological community in the western Pacific Ocean to the global cold-climate events and the close correlation between the formation of the crust and the global climate change.
基金China International Seabed Area R & D Program under contract No.DYXM-115-01-1
文摘In 2001, the International Seabed Authority (ISBA) initiated the consideration relating to the Regulations for Prospecting and Exploration for Hydrothermal Polymetallic Sulphides and Cobalt-rich Ferromanganese Crusts in the Area at its 7th session. Since then, the consideration of the Regulations has been mainly focused on the size of areas to be allocated for exploration and exploitation of the crusts. This paper, based on the investigation data and the analysis of the distribution characteristics of the crusts, suggests a model for determining the size of areas for exploration and exploitation of the crusts, taking into account various factors such as production scale, crust thickness and grade, mineable area proportion, recovery efficiency, exploration venture, and so on. Through the modeling, the paper suggests that the exploration area (the area covered by each application for approval of a plan of work for exploration of cobalt-rich crusts) shall be 4 856 km2 and the exploitation area (the mine site area) shall be 1 214 km2, for 20 years of 1 million wet tonnes annual production.
基金This work was sponsored by the International Ocean Area Research & Development Tenth Five-Year Plan Programme (Grant No. DY105-04-01-9).
文摘An ammonia leaching process was utilized to extract Co, Ni and Cu from oceanic polymetallic nodules, whereas an acid leaching process was utilized to extract Co, Ni, Cu, Zn and Mn from cobalt-rich crusts. Both processes produced nanometer materials-ammonia leaching residue and acid leaching residue. A systematic study was conducted on the phase, composition and physicochemistry properties of these residues. The result shows that both residues contain a large amount of nanometer minerals. Ammonia leaching residue mainly consists of rhodochrosite, with the average grain diameter of 17.9 nm; whereas the acid leaching residue mainly consists of well-developed bassanite, with the average grain deameter of 9.5 nm. The bassanite also has a microporous structure, the volume of the pore space is 1.23×10-2 mL/g. Both the ammonia and acid leaching residues have a large specific surface area, and they display a strong adsorption capacity to saturate sodium chloride vapour, N2 and SO2. Both residues have high
文摘Noble gas isotopic compositions of various layers in three-layered (outer, porous and compact layers) cobalt-rich ferromanganese crusts and their basaltic and phosphorite substrates from the western Pacific Ocean were analyzed by using a high vacuum gas mass spectrum. The analytical results show that the noble gases in the Co-rich crusts have derived mainly from the ambient seawater, extraterrestrial grains such as interplanetary dust particles (IDPs) and wind-borne continental dust grains, and locally formation water in the submarine sediments, but different noble gases have different sources. He in the crusts derives predominantly from the extraterrestrial grains, with a negligible amount of radiogenic He from the eolian dust grains. Ar is sourced mainly from the dissolved air in the seawater and insignificantly from radiogenic Ar in the eolian continental dust grains or the formation water. Xe and Ne derive mainly from the seawater, with minor amounts of extraterrestrial Xe and Ne in the IDPs. Compared with the porous and outer layers, the compact layer has a relatively high 4He content and lower 3He/4He ratios, suggesting that marine phosphatization might have greatly modified the noble gas isotopic compositions of the crusts. Besides, the 3He/4He values of the basaltic substrates of the cobalt-rich crusts are very low and their R/R. ratios are mostly 〈0.1 R., which are similar to that of phosphorite substrates (0.087 R.), but much lower than that of fresh submarine MORB (8.75±14 Ra) or seamount basalts (3-43 Ra), implying that the basaltic substrates have suffered strong water/rock interaction and reacted with radiogenic ^4He and P-rich upwelling marine currents during phosphatization. The trace elements released in the basalt/seawater interaction might favor the growth of cobalt-rich crusts. The relatively low ^3He/^4He values in the seamount basalts may be used as an important exploration criterion for the cobalt-rich ferromanganese crusts.
文摘Determining the upper boundary of the cobalt-rich crust distribution of a guyot is important for estimating the mineral resources available, however, it has also long been an unsolved question. Correlations between the sub-bottom structures, revealed by sub-bottom profiling, and crust distribution can be revealed for the first time by the synchronous application of sub-bottom profiling and deep-sea video recording. The lower boundary of the sediment corresponds with the upper boundary of the crust. By analysis of these two kinds of data, the lower boundary of the sediment can be determined; therefore, the upper boundary of the crust distribution can be deduced. According to this method of analysis, the upper boundary of water depth of crust distribution of a seamount in the western Pacific is about 1 560 m.
基金supported by grant DY95-08-05 from the China Ocean Mineral Resources R&D Associationthe National Natural Science Foundation of China(Grant 40373002).
文摘A detailed study on a small scale of the effect of phosphatization on the chemistry of marine cobalt-rich ferromanganese crusts supplies useful information for the evaluation and comprehensive utilization of crust mineral resources. Sub-samples from top to bottom of a 10-cm thick sample from the NW Pacific Magellan seamount were taken at 5 mm intervals. The concentration profiles of ore-forming and rare earth elements show that obvious differences exist between young unphosphatized crusts and old phosphatized crusts. In the old crusts Fe, Mn, Si, Al, Zn, Mg, Co, Ni and Cu elements are depleted and Ca, P, Sr, Ba and Pb elements are enriched. The order of depletion is Co > Ni > Mg > Al > Mn > Si> Cu > Zn > Fe, while the order of enrichment is P > Ca > Ba > Pb > Sr. The phosphate mineral controls the concentration variation of the ore-forming elements in crusts and causes loss of the main ore-forming elements such as Co and Ni. The phosphatization also affects the abundance of REEs in the crusts. REEs are more abundant and the content of Ce in old crusts is higher than that in young crusts, however, the pattern of REEs and their fractionation characteristics in new and old crusts are not fundamentally changed. A Y-positive anomaly in old crusts has no relationship to the phosphatization.