The current advances in the study of geochemistry and paleo-oceanography of the Co-rich crust are reviewed in this paper. We summarize the study of geochemistry of the Co-rich crust, discuss the diffusion of elements ...The current advances in the study of geochemistry and paleo-oceanography of the Co-rich crust are reviewed in this paper. We summarize the study of geochemistry of the Co-rich crust, discuss the diffusion of elements in the Co-rich crust and the exchange with ambient seawater. Besides, we discuss the effect of phosphatization and substrate rocks on the composition of the Co-rich crust. We also introduce the application of stable isotopes(including the stable isotopes of Pb, Nd, and Hf), radioactive isotopes (including the radioactive isotopes of Be, U and Th), and elements (including the major elements, minor elements and rare earth elements) to the study of paleo-oceanography of the Co-rich crust.展开更多
Results on the magneto-optical investigation of near-surface micromagnetic structure (MMS) of Co69Fe4Si12B15 amorphous wires 10～50 μm in diameter are presented. The wires were prepared by the rapid solidification te...Results on the magneto-optical investigation of near-surface micromagnetic structure (MMS) of Co69Fe4Si12B15 amorphous wires 10～50 μm in diameter are presented. The wires were prepared by the rapid solidification technique. The magnetic field H was applied along or perpendicular to the wire length. By scanning the light spot of 1 μm-diameter along the wire length, distributions of magnetization components (both parallel and perpendicular to the applied magnetic field) and also local hysteresis characteristics of the wires were measured. It was experimentally established that owing to the compressive stresses from quenching coupled with negative magnetostriction of Co-rich amorphous materials, the examined microwires have a circumferential magnetic anisotropy. In consequence, there are the near-surface alternate left- and right-handled circular domains in these samples. The dependencies of the circular domain width on the wire diameter and length were found. It was discovered that in the axial magnetic field local hysteresis loops are unhysteretic. It was proved that in this case the dominant mechanism of the wire magnetization reversal is rotation of local magnetization vectors in circular domains.展开更多
For optimizing the cutting depth of spiral drum type cutting head,the relations among collecting ratio,interfusing ratio of mullock and cutting depth of the mining cobalt-rich crusts in ocean were discussed.Furthermor...For optimizing the cutting depth of spiral drum type cutting head,the relations among collecting ratio,interfusing ratio of mullock and cutting depth of the mining cobalt-rich crusts in ocean were discussed.Furthermore,the multi-extremum problem about cutting depth was analyzed in mining at a certain interfusing ratio of mullock.Through introducing genetic algorithm(GA),the cutting depth-control problem when the collecting ratio is maximized by controlling the interfusing ratio of mullock was solved with global-optimization-search algorithms.Then optimization theory for cutting depth in mining cobalt-rich crusts by GA,and computer programming were given to realize the algorithm.The computation result of actual data proves the validity of this method.展开更多
Up to now, accurate determination of the growth age and hiatuses of the Co-rich crust is still a difficult work, which constrains the researches on the genesis, growth process, controlling factors, regional tectonics,...Up to now, accurate determination of the growth age and hiatuses of the Co-rich crust is still a difficult work, which constrains the researches on the genesis, growth process, controlling factors, regional tectonics, paleo-oceanographic background, etc. of the Co-rich crust. This paper describes our work in determining the initial growth age of the Co-rich crust to be of the late Cretaceous Campanian Stage (about 75-80 Ma), by selecting the Co-rich crust with clear multi-layer structures in a central Pacific seamount for layer-by-layer sample analysis and using a number of chronological methods, such as Co flux dating, dating by correlation with 187Os/188Os evolution curves of seawater, and stratigraphic divi- sion by calcareous nannofossils. We have also discovered growth hiatuses with different time intervals in the early Paleocene, middle Eocene, late Eocene and early-middle Miocene, respectively. These re- sults have provided an important age background for further researches on the Co-rich crust growth process and the paleo-oceanographic environment evolution thereby revealed in the said region.展开更多
Co-rich seamount crusts have been shown to possess great potential for providing information on paleoceanographic and paleoclimatic changes. High resolution data are essential to decipher and correctly understand such...Co-rich seamount crusts have been shown to possess great potential for providing information on paleoceanographic and paleoclimatic changes. High resolution data are essential to decipher and correctly understand such high-density records. With the development of modern microprobe techniques, detailed sampling of crusts can be performed and it is possible to retrieve detailed information about envi- ronmental changes recorded in the seamount crusts. We report here geochemical results of more than 40 elements (including all rare earth elements) of four Co-rich seamount crust samples, which were collected from seamounts in the central and western Pacific Ocean. These data were obtained with two micro-probe techniques: Electron Probe Micro Analyzer and Laser Ablation Inductively Coupled Plasma Mass Spectrometry. The chronological framework of the seamount crust samples was determined using the cos- mogenic 10Be and the Co-chronometer. Records of elemental composition, P, and Al/(Fe + Mn) and Y/Ho ratios across the sections of the four samples are used to identify paleoceanographic and paleoclimatic events over the past ~30 Ma. These data show that: (1) Al/(Fe + Mn) in the western Pacific seamount crust is a useful proxy for the assessment of changes of source materials related to the variability of the Asian monsoon; (2) P and Y/Ho can be used as proxies to infer biogenic episodes. Finally we discuss the methodology related to dating and micro-probe analysis used in crust study.展开更多
Due to their slow growth rates, seamount Co-rich crusts are very difficult to date with high resolution and precision. This paper is to test the use of orbital pacing on the growth profile of crusts to determine high-...Due to their slow growth rates, seamount Co-rich crusts are very difficult to date with high resolution and precision. This paper is to test the use of orbital pacing on the growth profile of crusts to determine high-resolution age and growth rate. Crust CB14 from the central Pacific Ocean was selected for this study. We first examined the growth pattern in detail under a reflected-light microscope and ascertained that the growth environment was stable for the sub-layer 1 (0-3 mm). We then used electron micro-probe line-scanning to obtain elemental profiles. The pattern of the power spectrum analysis of the Al-profile revealed that there are significant cycles of 113.9, 87.8, 51.5, 42.2 and 25.8 μm. These cycles correspond to the Milankovitch cycles of 53.1, 41, 24, 19.7 and 12 ka, respectively, and yield the growth rate of about 2.14 mm/Ma and an age of about 1.40 Ma for the boundary between the sub-layer 1 and sub-layer 2. We also used a drilling machine with a numerically controlled drive to obtain high-resolution samples at 0.1mm intervals, and used the 230Thex/232Th method to date the samples. For the uppermost 1.3 mm, the growth rate was about 2.15 mm/Ma, and the age for the layer at the depth of 3 mm was about 1.40 Ma, which coincides perfectly with the results obtained from orbital pacing. Thus, it is considered that orbital pacing is a new and effective method to determine the growth rate of the seamount Co-rich crust. This method is applicable for establishing a high-resolution age frame for the crusts of the world's oceans.展开更多
Based on its microstructure, Co-rich crust A1-1 from seamount Allison, central Pacific, was scraped at averaged interval of 1.3 mm to measure osmium isotopic composition, and subsequently to establish the 187Os/188Os ...Based on its microstructure, Co-rich crust A1-1 from seamount Allison, central Pacific, was scraped at averaged interval of 1.3 mm to measure osmium isotopic composition, and subsequently to establish the 187Os/188Os profile of scraping section of the crust. By observing the variation of 187Os/188Os under 10Be chronology and matching it to the well-known seawater Os isotope evolution of the past 40 Ma, two growth hiatuses (H1 and H2) occurring in the periods respectively between 13.6 and 29.6 Ma and between 8 and 9.8 Ma in the crust were recognized. According to the two hiatuses, the dating scheme for each scraped layer of the crust was suggested. For the upper layers younger than 6.8Ma, their growth ages were calibrated under 10Be chronology; for the lower layers older than 6.8Ma, their growth ages were obtained from 187Os/188Os evaluation curve by linear interpolation. Hereby, the age for the most inner layer of the crust was determined to be 39.5 Ma. H1 and H2 exactly correspond to the boundary between phosphatization and non-phosphatization and volcanic ash layer in the crust, respectively.展开更多
文摘The current advances in the study of geochemistry and paleo-oceanography of the Co-rich crust are reviewed in this paper. We summarize the study of geochemistry of the Co-rich crust, discuss the diffusion of elements in the Co-rich crust and the exchange with ambient seawater. Besides, we discuss the effect of phosphatization and substrate rocks on the composition of the Co-rich crust. We also introduce the application of stable isotopes(including the stable isotopes of Pb, Nd, and Hf), radioactive isotopes (including the radioactive isotopes of Be, U and Th), and elements (including the major elements, minor elements and rare earth elements) to the study of paleo-oceanography of the Co-rich crust.
基金scientific Korea-Russia Manpower exchange programScience & Technology Policy instituteRussian Fund of Fundamental invest
文摘Results on the magneto-optical investigation of near-surface micromagnetic structure (MMS) of Co69Fe4Si12B15 amorphous wires 10～50 μm in diameter are presented. The wires were prepared by the rapid solidification technique. The magnetic field H was applied along or perpendicular to the wire length. By scanning the light spot of 1 μm-diameter along the wire length, distributions of magnetization components (both parallel and perpendicular to the applied magnetic field) and also local hysteresis characteristics of the wires were measured. It was experimentally established that owing to the compressive stresses from quenching coupled with negative magnetostriction of Co-rich amorphous materials, the examined microwires have a circumferential magnetic anisotropy. In consequence, there are the near-surface alternate left- and right-handled circular domains in these samples. The dependencies of the circular domain width on the wire diameter and length were found. It was discovered that in the axial magnetic field local hysteresis loops are unhysteretic. It was proved that in this case the dominant mechanism of the wire magnetization reversal is rotation of local magnetization vectors in circular domains.
基金Project(50474052)supported by the National Natural Science Foundation of ChinaProject(2005) supported by the Youthful Teacher Skeleton Foundation of Hunan Province, ChinaProject supported by the Postdoctoral Foundation of China
文摘For optimizing the cutting depth of spiral drum type cutting head,the relations among collecting ratio,interfusing ratio of mullock and cutting depth of the mining cobalt-rich crusts in ocean were discussed.Furthermore,the multi-extremum problem about cutting depth was analyzed in mining at a certain interfusing ratio of mullock.Through introducing genetic algorithm(GA),the cutting depth-control problem when the collecting ratio is maximized by controlling the interfusing ratio of mullock was solved with global-optimization-search algorithms.Then optimization theory for cutting depth in mining cobalt-rich crusts by GA,and computer programming were given to realize the algorithm.The computation result of actual data proves the validity of this method.
基金China Ocean Mineral Resources Research and Development Associa-tion "10th Five Year" Topic (Grant No. DY105-01-04-14)International Science and Technology Cooperation Project from Ministry of Science and Technology of China (Grant No: 2006DFB21620)the National Natural Science Foundation of China (Grant No. 40706029)
文摘Up to now, accurate determination of the growth age and hiatuses of the Co-rich crust is still a difficult work, which constrains the researches on the genesis, growth process, controlling factors, regional tectonics, paleo-oceanographic background, etc. of the Co-rich crust. This paper describes our work in determining the initial growth age of the Co-rich crust to be of the late Cretaceous Campanian Stage (about 75-80 Ma), by selecting the Co-rich crust with clear multi-layer structures in a central Pacific seamount for layer-by-layer sample analysis and using a number of chronological methods, such as Co flux dating, dating by correlation with 187Os/188Os evolution curves of seawater, and stratigraphic divi- sion by calcareous nannofossils. We have also discovered growth hiatuses with different time intervals in the early Paleocene, middle Eocene, late Eocene and early-middle Miocene, respectively. These re- sults have provided an important age background for further researches on the Co-rich crust growth process and the paleo-oceanographic environment evolution thereby revealed in the said region.
基金the Key Laboratory of Marine Sedimentology and Environmental Geol- ogy, State Oceanic Administration (Grant No. MASEG200602)China Ocean Mineral Resources Research and Development Association (Grant No. DY105-01-04-05)Programme of Excellent Young Scientists of the Ministry of Land and Resources
文摘Co-rich seamount crusts have been shown to possess great potential for providing information on paleoceanographic and paleoclimatic changes. High resolution data are essential to decipher and correctly understand such high-density records. With the development of modern microprobe techniques, detailed sampling of crusts can be performed and it is possible to retrieve detailed information about envi- ronmental changes recorded in the seamount crusts. We report here geochemical results of more than 40 elements (including all rare earth elements) of four Co-rich seamount crust samples, which were collected from seamounts in the central and western Pacific Ocean. These data were obtained with two micro-probe techniques: Electron Probe Micro Analyzer and Laser Ablation Inductively Coupled Plasma Mass Spectrometry. The chronological framework of the seamount crust samples was determined using the cos- mogenic 10Be and the Co-chronometer. Records of elemental composition, P, and Al/(Fe + Mn) and Y/Ho ratios across the sections of the four samples are used to identify paleoceanographic and paleoclimatic events over the past ~30 Ma. These data show that: (1) Al/(Fe + Mn) in the western Pacific seamount crust is a useful proxy for the assessment of changes of source materials related to the variability of the Asian monsoon; (2) P and Y/Ho can be used as proxies to infer biogenic episodes. Finally we discuss the methodology related to dating and micro-probe analysis used in crust study.
基金Supported by China Ocean Mineral Resources R & P Association (Grant No. DY105-01-01-08)National Natural Science Foundation of China (Grant Nos. 40106005, 40476050)
文摘Due to their slow growth rates, seamount Co-rich crusts are very difficult to date with high resolution and precision. This paper is to test the use of orbital pacing on the growth profile of crusts to determine high-resolution age and growth rate. Crust CB14 from the central Pacific Ocean was selected for this study. We first examined the growth pattern in detail under a reflected-light microscope and ascertained that the growth environment was stable for the sub-layer 1 (0-3 mm). We then used electron micro-probe line-scanning to obtain elemental profiles. The pattern of the power spectrum analysis of the Al-profile revealed that there are significant cycles of 113.9, 87.8, 51.5, 42.2 and 25.8 μm. These cycles correspond to the Milankovitch cycles of 53.1, 41, 24, 19.7 and 12 ka, respectively, and yield the growth rate of about 2.14 mm/Ma and an age of about 1.40 Ma for the boundary between the sub-layer 1 and sub-layer 2. We also used a drilling machine with a numerically controlled drive to obtain high-resolution samples at 0.1mm intervals, and used the 230Thex/232Th method to date the samples. For the uppermost 1.3 mm, the growth rate was about 2.15 mm/Ma, and the age for the layer at the depth of 3 mm was about 1.40 Ma, which coincides perfectly with the results obtained from orbital pacing. Thus, it is considered that orbital pacing is a new and effective method to determine the growth rate of the seamount Co-rich crust. This method is applicable for establishing a high-resolution age frame for the crusts of the world's oceans.
基金the Ministry of Science and Technology and the China Oceanic Min-eral Resource Research and Development Association (COMRA) (Grant Nos. 2006DFB21620 and DY105-01-01-09)
文摘Based on its microstructure, Co-rich crust A1-1 from seamount Allison, central Pacific, was scraped at averaged interval of 1.3 mm to measure osmium isotopic composition, and subsequently to establish the 187Os/188Os profile of scraping section of the crust. By observing the variation of 187Os/188Os under 10Be chronology and matching it to the well-known seawater Os isotope evolution of the past 40 Ma, two growth hiatuses (H1 and H2) occurring in the periods respectively between 13.6 and 29.6 Ma and between 8 and 9.8 Ma in the crust were recognized. According to the two hiatuses, the dating scheme for each scraped layer of the crust was suggested. For the upper layers younger than 6.8Ma, their growth ages were calibrated under 10Be chronology; for the lower layers older than 6.8Ma, their growth ages were obtained from 187Os/188Os evaluation curve by linear interpolation. Hereby, the age for the most inner layer of the crust was determined to be 39.5 Ma. H1 and H2 exactly correspond to the boundary between phosphatization and non-phosphatization and volcanic ash layer in the crust, respectively.
