In this work,we perform a Bayesian inference of the crust-core transition density ρ_(t) of neutron stars based on the neutron-star radius and neutron-skin thickness data using a thermodynamical method.Uniform and Gau...In this work,we perform a Bayesian inference of the crust-core transition density ρ_(t) of neutron stars based on the neutron-star radius and neutron-skin thickness data using a thermodynamical method.Uniform and Gaussian distributions for the ρ_(t) prior were adopted in the Bayesian approach.It has a larger probability of having values higher than 0.1 fm^(−3) for ρ_(t) as the uniform prior and neutron-star radius data were used.This was found to be controlled by the curvature K_(sym) of the nuclear symmetry energy.This phenomenon did not occur if K_(sym) was not extremely negative,namely,K_(sym)>−200 MeV.The value ofρ_(t) obtained was 0.075_(−0.01)^(+0.005) fm^(−3) at a confidence level of 68%when both the neutron-star radius and neutron-skin thickness data were considered.Strong anti-correlations were observed between ρ_(t),slope L,and curvature of the nuclear symmetry energy.The dependence of the three L-K_(sym) correlations predicted in the literature on crust-core density and pressure was quantitatively investigated.The most probable value of 0.08 fm^(−3) for ρ_(t) was obtained from the L-K_(sym) relationship proposed by Holt et al.while larger values were preferred for the other two relationships.展开更多
A series of selective dissolution experunents were conducted on the hydrogeinc ferromanganese crusts collected near Line Island to study the geochemistry of Mn, Fe, Cu, Co, Ni and Ti. Despite of the fact that the very...A series of selective dissolution experunents were conducted on the hydrogeinc ferromanganese crusts collected near Line Island to study the geochemistry of Mn, Fe, Cu, Co, Ni and Ti. Despite of the fact that the very close intergrowth between amorphous ferric oxyhydroxides and 6-MnO2 exists in the hydrogenic ferromanganese crusts, there is no isomorphous substitution between iron and manganese. This is because the two elements in oxides have different crystal chemistry and geochemistry, such assertion bemg in agreement with the results of selective dissolution experiments. Transitional metal elements such as Cu, Co, Ni and Ti are enriched in different phases, i.e. Ni and Co are incorporated into 6-MnO2 while Cu and Ti are incorporated into ferric oxyhy- droxides. The distributions of the elements in amorphous ferric oxyhydroxides and δ-MnO2 are controlled by the existing states of the elements in the seawater and the crystal chemistry and geochemistry of these elements/inns in oxides.展开更多
Neogene volcanic rocks in the Belog Co area, Qiangtang, northern Tibet, are represented by a typical intermediate-basic and intermediate alkaline rock association, with latite-trachyte as the main rock type. The resul...Neogene volcanic rocks in the Belog Co area, Qiangtang, northern Tibet, are represented by a typical intermediate-basic and intermediate alkaline rock association, with latite-trachyte as the main rock type. The results of chemical analysis are: SiO2=52%–62%, Al2O3>15%, Na2O/K2O>1 and MgO<3.30%. In addition, the volcanic rocks are LREE-enriched with LREE/HREE=10–13, (La/Yb)N=15–19, and show a weak negative Eu anomaly with δEu=0.71–0.89. The close relationship between Mg# and SiO2 and the co-variation of the magmatophile elements and ultra-magmatophile elements such as La/Sm-La and Cr-Tb indicate that this association of volcanic rocks is the product of comagmatic fractional crystallization. The rock association type and lower Sm/Yb values (Sm/Yb=3.23–3.97) imply that this association of volcanic rocks should have originated from partial melting of spinel lherzolite in the lithospheric mantle. On the other hand, the weak negative Eu anomaly and relative depletion in Nb, Ta and Ti reflect the features of terrigenous magma. So the Neogene Belog Co alkaline volcanic rocks should be the result of partial melting of the special crust-mantle transition zone on the Qinghai-Tibet Plateau.展开更多
This study deals with complexity, frequency spectrum and velocity model of the crust-mantle transitional zone in different tectonic units along the northeast margin of Qinghai-Xizang plateau, based on PmP waveform dat...This study deals with complexity, frequency spectrum and velocity model of the crust-mantle transitional zone in different tectonic units along the northeast margin of Qinghai-Xizang plateau, based on PmP waveform data from two deep seismic sounding profiles passing through the area. It reveals that Moho has stable tectonic features in Ordos and Lingzhong basins, where crust and mantle are coupled as first-order discontinuity. Moho shows obvious signs of activity in Haiyuan seismic region and in the contact zone between Bayanhar block and Qaidam block. Crust and mantle in these two areas are coupled as complicated crust-mantle transitional zone consisting of multiple laminae with alternate high and low velocities, totaling 20 km in thickness. The difference between Moho of different tectonic units reflects heterogeneity of the coupled crust-mantle zone; the difference between fine structures of Haiyuan seismic region and Maqin fault zone reflects different deep material composition of the two continent-continent collision zones and the interaction between blocks.展开更多
In this paper the fine structure of crust mantle transition zone in Western Yunnan Province is analysed and discussed based on the reflection phases from Moho discontinuity in Project Western Yunnan 86~87. ...In this paper the fine structure of crust mantle transition zone in Western Yunnan Province is analysed and discussed based on the reflection phases from Moho discontinuity in Project Western Yunnan 86~87. It shows that in two points: in the north 27.64 km from shot point Jinggu and south 58.74 km from shot point Zhiti, there are transition zones of group of thin layers with inverse velocity.These two reflection points are both situated in the lower velocity anomaly zone in the top of upper mantle. The crust of this region is more seismicity. Maybe the unusual structure of this transition zone is related with the characteristics of this region. This paper discusses the possible geological interpretation model for this transition zone, and also makes suggestion about its application in earthquake prediction.展开更多
Abstract: The great majority of the Palaeozoic orogenic belts of Central Asia are of the intercontinental type, whose evolution always follows a five-stage model, i.e. the basal continental crust-extensional transitio...Abstract: The great majority of the Palaeozoic orogenic belts of Central Asia are of the intercontinental type, whose evolution always follows a five-stage model, i.e. the basal continental crust-extensional transitional crust-oceanic crust-convergent transitional crust-new continental crust model. The stage for the extensional transitional crust is a pretty long, independent and inevitable phase. The dismembering mechanism of the basal continental crust becoming an extensional continental crust is delineated by the simple shear model put forward by Wernike (1981). The continental margins on the sides of a gently dipping detachment zone and moving along it are asymmetric: one side is of the nonmagmatic type and the other of the magmatic type with a typical bimodal volcanic formation. In the latter case, however, they were often confused with island arcs. This paper discusses the five-stage process of the crustal evolution of some typical orogenic belts in Xinjiang.展开更多
The fine structure of crust mantle transition zone in Yanqing Hailai(Yan Huai basin) basin has been analyzed and discussed by using the data of Yanqing Hailai deep seismic reflection profile and Beijing Huailai ...The fine structure of crust mantle transition zone in Yanqing Hailai(Yan Huai basin) basin has been analyzed and discussed by using the data of Yanqing Hailai deep seismic reflection profile and Beijing Huailai Fengzhen deep seismic sounding profile obtained respectively in 1992 and in 1993. The primary model is established based on CDP stacking profile. The phases of seismic refraction waves and wide angle reflection waves are analyzed, travel time inversion is carried out and 2 D ray tracing is computed. Synthetic seismograms are completed by using re flectivity method for waveform fitting of phases P M and P M′, they are reflection waves from both the upper and the lower boundaries of the crust mantle transition zone in this basin. The results show that the P M′ reflection waves are stronger at some points and come from the lower boundary of Moho discontinuity. It is confirmed and inter preted that the Moho discontinuity in Yanqing Hailai basin consists of a group of thin layers with alternatively higher and lower velocities.展开更多
Weathering crust of carbonate rocks refers to the terra rossa formation, which is derived from limestone, dolomite and transitional rocks between the two. Terra rossa is widespread in the tropical and subtropical area...Weathering crust of carbonate rocks refers to the terra rossa formation, which is derived from limestone, dolomite and transitional rocks between the two. Terra rossa is widespread in the tropical and subtropical areas over the world. It is also well distributed in southern China, such as Yunnan. Guizhou Sichuan, Hunan, Guangxi and other provinces. Its thickness is generally 7-8展开更多
Compression wave velocity Vp has been measured on 10 representative rock samples from the Early Mesozoic granulite and mafic-ultramafic cumulate xenoliths population from the Harqin area of the Inner Mongolia Autonomo...Compression wave velocity Vp has been measured on 10 representative rock samples from the Early Mesozoic granulite and mafic-ultramafic cumulate xenoliths population from the Harqin area of the Inner Mongolia Autonomous Region (for short Inner Mongolia) as an aid to interpreting in-situ seismic velocity data and investigating velocity variation with depth in a mafic lower crust. The experiments have been carried out at constant confining pressures up to 1 000 MPa and temperatures ranging from 20 to around 1 300℃, using the ultrasonic transmission technique. After corrections for estimated in situ crustal pressures and temperatures, elastic wave velocities range from 6.5 to 7.4 km · s-1, indicating that they are components of the Early Mesozoic crust-mantle transitional zone. Combining with previous experimental data, we have also reestablished the Early-Mesozoic continental compression velocity profile and compared it with those of the present and of the different tectonic environments in the world. The result shows that it is similar to the velocity pattern of the extensional tectonic area, providing new clues to the Mesozoic continental structure of the North China Craton.展开更多
基金supported by the Shanxi Provincial Foundation for Returned Overseas Scholars (No. 20220037)Natural Science Foundation of Shanxi Province (No. 20210302123085)Discipline Construction Project of Yuncheng University
文摘In this work,we perform a Bayesian inference of the crust-core transition density ρ_(t) of neutron stars based on the neutron-star radius and neutron-skin thickness data using a thermodynamical method.Uniform and Gaussian distributions for the ρ_(t) prior were adopted in the Bayesian approach.It has a larger probability of having values higher than 0.1 fm^(−3) for ρ_(t) as the uniform prior and neutron-star radius data were used.This was found to be controlled by the curvature K_(sym) of the nuclear symmetry energy.This phenomenon did not occur if K_(sym) was not extremely negative,namely,K_(sym)>−200 MeV.The value ofρ_(t) obtained was 0.075_(−0.01)^(+0.005) fm^(−3) at a confidence level of 68%when both the neutron-star radius and neutron-skin thickness data were considered.Strong anti-correlations were observed between ρ_(t),slope L,and curvature of the nuclear symmetry energy.The dependence of the three L-K_(sym) correlations predicted in the literature on crust-core density and pressure was quantitatively investigated.The most probable value of 0.08 fm^(−3) for ρ_(t) was obtained from the L-K_(sym) relationship proposed by Holt et al.while larger values were preferred for the other two relationships.
基金supported by China Ocean Mineral Resources Research and Development Association (COMRA) (DY105-05-01-05)China Ministry of Education (205089)China National Natural Science Foundation (40076015).
文摘A series of selective dissolution experunents were conducted on the hydrogeinc ferromanganese crusts collected near Line Island to study the geochemistry of Mn, Fe, Cu, Co, Ni and Ti. Despite of the fact that the very close intergrowth between amorphous ferric oxyhydroxides and 6-MnO2 exists in the hydrogenic ferromanganese crusts, there is no isomorphous substitution between iron and manganese. This is because the two elements in oxides have different crystal chemistry and geochemistry, such assertion bemg in agreement with the results of selective dissolution experiments. Transitional metal elements such as Cu, Co, Ni and Ti are enriched in different phases, i.e. Ni and Co are incorporated into 6-MnO2 while Cu and Ti are incorporated into ferric oxyhy- droxides. The distributions of the elements in amorphous ferric oxyhydroxides and δ-MnO2 are controlled by the existing states of the elements in the seawater and the crystal chemistry and geochemistry of these elements/inns in oxides.
基金This project was financially supported by the National Natural Science Foundation of China (Grant Nos. 40572050 and 40272042) the Teaching and Research Award Program for 0utstanding Young Teachers at Higher Education Institutions, Ministry of Education (M0E), China.
文摘Neogene volcanic rocks in the Belog Co area, Qiangtang, northern Tibet, are represented by a typical intermediate-basic and intermediate alkaline rock association, with latite-trachyte as the main rock type. The results of chemical analysis are: SiO2=52%–62%, Al2O3>15%, Na2O/K2O>1 and MgO<3.30%. In addition, the volcanic rocks are LREE-enriched with LREE/HREE=10–13, (La/Yb)N=15–19, and show a weak negative Eu anomaly with δEu=0.71–0.89. The close relationship between Mg# and SiO2 and the co-variation of the magmatophile elements and ultra-magmatophile elements such as La/Sm-La and Cr-Tb indicate that this association of volcanic rocks is the product of comagmatic fractional crystallization. The rock association type and lower Sm/Yb values (Sm/Yb=3.23–3.97) imply that this association of volcanic rocks should have originated from partial melting of spinel lherzolite in the lithospheric mantle. On the other hand, the weak negative Eu anomaly and relative depletion in Nb, Ta and Ti reflect the features of terrigenous magma. So the Neogene Belog Co alkaline volcanic rocks should be the result of partial melting of the special crust-mantle transition zone on the Qinghai-Tibet Plateau.
基金Chinese Joint Seismological Science Foundation (102025, 104027).Contribution No. RCEG200210, Geophysical Exploration Center, China Earthquake Administration.
文摘This study deals with complexity, frequency spectrum and velocity model of the crust-mantle transitional zone in different tectonic units along the northeast margin of Qinghai-Xizang plateau, based on PmP waveform data from two deep seismic sounding profiles passing through the area. It reveals that Moho has stable tectonic features in Ordos and Lingzhong basins, where crust and mantle are coupled as first-order discontinuity. Moho shows obvious signs of activity in Haiyuan seismic region and in the contact zone between Bayanhar block and Qaidam block. Crust and mantle in these two areas are coupled as complicated crust-mantle transitional zone consisting of multiple laminae with alternate high and low velocities, totaling 20 km in thickness. The difference between Moho of different tectonic units reflects heterogeneity of the coupled crust-mantle zone; the difference between fine structures of Haiyuan seismic region and Maqin fault zone reflects different deep material composition of the two continent-continent collision zones and the interaction between blocks.
文摘In this paper the fine structure of crust mantle transition zone in Western Yunnan Province is analysed and discussed based on the reflection phases from Moho discontinuity in Project Western Yunnan 86~87. It shows that in two points: in the north 27.64 km from shot point Jinggu and south 58.74 km from shot point Zhiti, there are transition zones of group of thin layers with inverse velocity.These two reflection points are both situated in the lower velocity anomaly zone in the top of upper mantle. The crust of this region is more seismicity. Maybe the unusual structure of this transition zone is related with the characteristics of this region. This paper discusses the possible geological interpretation model for this transition zone, and also makes suggestion about its application in earthquake prediction.
文摘Abstract: The great majority of the Palaeozoic orogenic belts of Central Asia are of the intercontinental type, whose evolution always follows a five-stage model, i.e. the basal continental crust-extensional transitional crust-oceanic crust-convergent transitional crust-new continental crust model. The stage for the extensional transitional crust is a pretty long, independent and inevitable phase. The dismembering mechanism of the basal continental crust becoming an extensional continental crust is delineated by the simple shear model put forward by Wernike (1981). The continental margins on the sides of a gently dipping detachment zone and moving along it are asymmetric: one side is of the nonmagmatic type and the other of the magmatic type with a typical bimodal volcanic formation. In the latter case, however, they were often confused with island arcs. This paper discusses the five-stage process of the crustal evolution of some typical orogenic belts in Xinjiang.
文摘The fine structure of crust mantle transition zone in Yanqing Hailai(Yan Huai basin) basin has been analyzed and discussed by using the data of Yanqing Hailai deep seismic reflection profile and Beijing Huailai Fengzhen deep seismic sounding profile obtained respectively in 1992 and in 1993. The primary model is established based on CDP stacking profile. The phases of seismic refraction waves and wide angle reflection waves are analyzed, travel time inversion is carried out and 2 D ray tracing is computed. Synthetic seismograms are completed by using re flectivity method for waveform fitting of phases P M and P M′, they are reflection waves from both the upper and the lower boundaries of the crust mantle transition zone in this basin. The results show that the P M′ reflection waves are stronger at some points and come from the lower boundary of Moho discontinuity. It is confirmed and inter preted that the Moho discontinuity in Yanqing Hailai basin consists of a group of thin layers with alternatively higher and lower velocities.
文摘Weathering crust of carbonate rocks refers to the terra rossa formation, which is derived from limestone, dolomite and transitional rocks between the two. Terra rossa is widespread in the tropical and subtropical areas over the world. It is also well distributed in southern China, such as Yunnan. Guizhou Sichuan, Hunan, Guangxi and other provinces. Its thickness is generally 7-8
文摘Compression wave velocity Vp has been measured on 10 representative rock samples from the Early Mesozoic granulite and mafic-ultramafic cumulate xenoliths population from the Harqin area of the Inner Mongolia Autonomous Region (for short Inner Mongolia) as an aid to interpreting in-situ seismic velocity data and investigating velocity variation with depth in a mafic lower crust. The experiments have been carried out at constant confining pressures up to 1 000 MPa and temperatures ranging from 20 to around 1 300℃, using the ultrasonic transmission technique. After corrections for estimated in situ crustal pressures and temperatures, elastic wave velocities range from 6.5 to 7.4 km · s-1, indicating that they are components of the Early Mesozoic crust-mantle transitional zone. Combining with previous experimental data, we have also reestablished the Early-Mesozoic continental compression velocity profile and compared it with those of the present and of the different tectonic environments in the world. The result shows that it is similar to the velocity pattern of the extensional tectonic area, providing new clues to the Mesozoic continental structure of the North China Craton.