Rare earth elements （REE） compositions and discriminant function were successfully used to examine high resolution sediment source changes in the northern Okinawa Trough over the last 24.1 ka, especially for the inf...Rare earth elements （REE） compositions and discriminant function were successfully used to examine high resolution sediment source changes in the northern Okinawa Trough over the last 24.1 ka, especially for the influence from the Yellow River and the Tsushima Warm Current （TWC） that has not been well solved. Variations of these parameters were clearly divided into three distinct depositional units. During Interval 1 （24.1-16.0 ka BP）, the paleo-Yellow River and the paleo-Yangtze River mouths were situated near the studied area and could have played major roles in the sedimentation therein. In Interval 2 （16.0-7.3 ka BP）, these river mouths gradually retreated with global sea-level rise, leading to less fluvial inputs from them to the northern Okinawa Trough. Meanwhile, formation of the TWC could carry some sediment loads of Taiwan to the studied core, especially during its late phase （8.0-7.3 ka BP）. Modem oceanographic conditions, with a predominance of the TWC, were finally established since the beginning of Interval 3, causing more ten＇igenous contribution from Taiwan to the studied area. Subsequently, modem depositional environments mainly influenced by the Yellow River, the Yangtze River, and the TWC were finally formed.展开更多
The inner relationship between Markov random field(MRF) and Markov chain random field(MCRF) is discussed. MCRF is a special MRF for dealing with high-order interactions of sparse data. It consists of a single spatial ...The inner relationship between Markov random field(MRF) and Markov chain random field(MCRF) is discussed. MCRF is a special MRF for dealing with high-order interactions of sparse data. It consists of a single spatial Markov chain(SMC) that can move in the whole space. Generally, the theoretical backbone of MCRF is conditional independence assumption, which is a way around the problem of knowing joint probabilities of multi-points. This so-called Naive Bayes assumption should not be taken lightly and should be checked whenever possible because it is mathematically difficult to prove. Rather than trap in this independence proving, an appropriate potential function in MRF theory is chosen instead. The MCRF formulas are well deduced and the joint probability of MRF is presented by localization approach, so that the complicated parameter estimation algorithm and iteration process can be avoided. The MCRF model is then applied to the lithofacies identification of a region and compared with triplex Markov chain(TMC) simulation. Analyses show that the MCRF model will not cause underestimation problem and can better reflect the geological sedimentation process.展开更多
The Shizitou molybdenum(Mo)deposit in Yongping,Jiangxi,is an important,recently discovered deposit in the eastern section of the Qin-Hang metallogenic belt.The Mo deposit is located in the outer contact zone behveen t...The Shizitou molybdenum(Mo)deposit in Yongping,Jiangxi,is an important,recently discovered deposit in the eastern section of the Qin-Hang metallogenic belt.The Mo deposit is located in the outer contact zone behveen the porphyritic biotite granite and the Neoproterozoic migmatite,and present in the deep central part of the intrusion.Re-Os dating and S and Pb isotopic analysis have been conducted to assess the metallogenesis of the Shizitou Mo deposit.S,Pb and Re isotopes show that the ore-forming materials were derived from the porphyritic biotite granitic magma,which originated from the mixing of mantle and crust.Re-Os dating of molybdenite from the ores gives a model age from 156.9±2.2 to 158.5±2.4 Ma,with a weighted mean age of 158±1 Ma and an isochron age of 158.0±2.5 Ma.Geological and geochemical characteristics of the ore deposit and the related granitoids indicate that the Shizitou deposit is a Climax-type Mo deposit.Based on previous studies of the Qin-Hang metaliogenic belt,two metallogenic events are believed to have occurred during 172-145 Ma and 137-132 Ma.These two metallogenic periods are consistent with the timing of two metallogenic peaks during the middle to late Jurassic and the Cretaceous in South China.These events represent responses to the partial backarc extension associated with the subduction of the Izanagi plate beneath the Eurasian continent and the rapid northeastward movement of the subducting Izanagi plate.展开更多
A new impregnated diamond bit was designed to solve the slipping problem when impregnated diamond bit was used for extra-hard, compact, and nonabrasive rock formation. Adding Si C grits into matrix, Si C grits can eas...A new impregnated diamond bit was designed to solve the slipping problem when impregnated diamond bit was used for extra-hard, compact, and nonabrasive rock formation. Adding Si C grits into matrix, Si C grits can easily be exfoliated from the surface of the matrix due to weak holding-force with matrix, which made the surface non-smooth. Three Ф36/24 mm laboratorial bits were manufactured to conduct a laboratory drilling test on zirconiacorundum refractory brick. The laboratory drilling test indicates that the abrasive resistance of the bit work layer is proportional to the Si C concentation. The higher the concentration, the weaker the abrasive resistance of matrix. The new impregnated diamond bit was applied to a mining area drilling construction in Jiangxi province, China. Field drilling application indicates that the ROP(rate of penetration) of the new bit is approximately two to three times that of the common bits. Compared with the common bits, the surface of the new bit has typical abrasive wear characteristics,and the metabolic rate of the diamond can be well matched to the wear rate of the matrix.展开更多
1 Introduction The Qin-Hang suture zone is the most important polymetallic metallogenic zone in southern China[1-2]and has the greatest resource potential.In recent years,a group of molybdenum(Mo)deposits have been di...1 Introduction The Qin-Hang suture zone is the most important polymetallic metallogenic zone in southern China[1-2]and has the greatest resource potential.In recent years,a group of molybdenum(Mo)deposits have been discovered in the northeastern part of the Qin-Hang belt[3].From Mar.2006to Dec.2014,the Jiangxi Copper Group Geological Exploration Engineering Co.,Ltd.conducted prospecting,展开更多
基金supported by the Public Science and Technology Research Funds Projects of Ocean,State Oceanic Administration of the People’s Republic of China (201005003)the National Natural Science Foundation of China (41230959,41106043,41076030)the National Basic Research Program of China (2007CB815903)
文摘Rare earth elements （REE） compositions and discriminant function were successfully used to examine high resolution sediment source changes in the northern Okinawa Trough over the last 24.1 ka, especially for the influence from the Yellow River and the Tsushima Warm Current （TWC） that has not been well solved. Variations of these parameters were clearly divided into three distinct depositional units. During Interval 1 （24.1-16.0 ka BP）, the paleo-Yellow River and the paleo-Yangtze River mouths were situated near the studied area and could have played major roles in the sedimentation therein. In Interval 2 （16.0-7.3 ka BP）, these river mouths gradually retreated with global sea-level rise, leading to less fluvial inputs from them to the northern Okinawa Trough. Meanwhile, formation of the TWC could carry some sediment loads of Taiwan to the studied core, especially during its late phase （8.0-7.3 ka BP）. Modem oceanographic conditions, with a predominance of the TWC, were finally established since the beginning of Interval 3, causing more ten＇igenous contribution from Taiwan to the studied area. Subsequently, modem depositional environments mainly influenced by the Yellow River, the Yangtze River, and the TWC were finally formed.
基金Project(2011ZX05002-005-006) supported by the National Science and Technology Major Research Program during the Twelfth Five-Year Plan of China
文摘The inner relationship between Markov random field(MRF) and Markov chain random field(MCRF) is discussed. MCRF is a special MRF for dealing with high-order interactions of sparse data. It consists of a single spatial Markov chain(SMC) that can move in the whole space. Generally, the theoretical backbone of MCRF is conditional independence assumption, which is a way around the problem of knowing joint probabilities of multi-points. This so-called Naive Bayes assumption should not be taken lightly and should be checked whenever possible because it is mathematically difficult to prove. Rather than trap in this independence proving, an appropriate potential function in MRF theory is chosen instead. The MCRF formulas are well deduced and the joint probability of MRF is presented by localization approach, so that the complicated parameter estimation algorithm and iteration process can be avoided. The MCRF model is then applied to the lithofacies identification of a region and compared with triplex Markov chain(TMC) simulation. Analyses show that the MCRF model will not cause underestimation problem and can better reflect the geological sedimentation process.
基金supported by the Innovation–driven Plan of Central South University(Project 1053320180985)the National Natural Science Foundation of China(Grant No.41702078)
文摘The Shizitou molybdenum(Mo)deposit in Yongping,Jiangxi,is an important,recently discovered deposit in the eastern section of the Qin-Hang metallogenic belt.The Mo deposit is located in the outer contact zone behveen the porphyritic biotite granite and the Neoproterozoic migmatite,and present in the deep central part of the intrusion.Re-Os dating and S and Pb isotopic analysis have been conducted to assess the metallogenesis of the Shizitou Mo deposit.S,Pb and Re isotopes show that the ore-forming materials were derived from the porphyritic biotite granitic magma,which originated from the mixing of mantle and crust.Re-Os dating of molybdenite from the ores gives a model age from 156.9±2.2 to 158.5±2.4 Ma,with a weighted mean age of 158±1 Ma and an isochron age of 158.0±2.5 Ma.Geological and geochemical characteristics of the ore deposit and the related granitoids indicate that the Shizitou deposit is a Climax-type Mo deposit.Based on previous studies of the Qin-Hang metaliogenic belt,two metallogenic events are believed to have occurred during 172-145 Ma and 137-132 Ma.These two metallogenic periods are consistent with the timing of two metallogenic peaks during the middle to late Jurassic and the Cretaceous in South China.These events represent responses to the partial backarc extension associated with the subduction of the Izanagi plate beneath the Eurasian continent and the rapid northeastward movement of the subducting Izanagi plate.
基金Project(51074180)supported by the National Natural Science Foundation of China
文摘A new impregnated diamond bit was designed to solve the slipping problem when impregnated diamond bit was used for extra-hard, compact, and nonabrasive rock formation. Adding Si C grits into matrix, Si C grits can easily be exfoliated from the surface of the matrix due to weak holding-force with matrix, which made the surface non-smooth. Three Ф36/24 mm laboratorial bits were manufactured to conduct a laboratory drilling test on zirconiacorundum refractory brick. The laboratory drilling test indicates that the abrasive resistance of the bit work layer is proportional to the Si C concentation. The higher the concentration, the weaker the abrasive resistance of matrix. The new impregnated diamond bit was applied to a mining area drilling construction in Jiangxi province, China. Field drilling application indicates that the ROP(rate of penetration) of the new bit is approximately two to three times that of the common bits. Compared with the common bits, the surface of the new bit has typical abrasive wear characteristics,and the metabolic rate of the diamond can be well matched to the wear rate of the matrix.
基金supported by the Innovation driven project of Central South University (2015CX008)
文摘1 Introduction The Qin-Hang suture zone is the most important polymetallic metallogenic zone in southern China[1-2]and has the greatest resource potential.In recent years,a group of molybdenum(Mo)deposits have been discovered in the northeastern part of the Qin-Hang belt[3].From Mar.2006to Dec.2014,the Jiangxi Copper Group Geological Exploration Engineering Co.,Ltd.conducted prospecting,
