The modern‘Penrose’definition of ophiolites is based largely on the Troodos complex of Cyprus,which contains a spectacular and well-exposed sheeted dike complex in which dike intrudes dike without intermediate scree...The modern‘Penrose’definition of ophiolites is based largely on the Troodos complex of Cyprus,which contains a spectacular and well-exposed sheeted dike complex in which dike intrudes dike without intermediate screens of展开更多
Understanding crust-mantle recycling through time,especially into the Archean,is crucial for understanding how the crust has grown from the mantle,and in turn how crustal material returned to the mantle alters the man...Understanding crust-mantle recycling through time,especially into the Archean,is crucial for understanding how the crust has grown from the mantle,and in turn how crustal material returned to the mantle alters the mantle reservoir.Recycling of crustal material,such as C-H-O-NS-P are especially important for understanding how processes such as subduction,melting,volcanism,and the release of volatiles have regulated climate and life on Earth over billions of years.展开更多
The analysis of strata between wells is fundamental in the study of oil and gas reservoirs. Automatic analysis of strata between wells, based on stratigraphic division of well logs, is realized using computer techniqu...The analysis of strata between wells is fundamental in the study of oil and gas reservoirs. Automatic analysis of strata between wells, based on stratigraphic division of well logs, is realized using computer techniques. We use a technique of dynamic waveform matching to build cross-well stratigraphic correlation relationships and automatically draw a path diagram of the cross-well stratigraphic contrast through piecewise line fitting, log character extraction, match cost calculation, and etc.. After analyzing many structure path diagrams between wells, 30 path patterns for normal faults, reverse faults, unconformities, synsedimentary faults, listric faults, pinch-outs, and so on were summarized and the path diagram patterns and correlation conceptions are presented. The application analysis in Dagang Oil Field shows that this method is effective.展开更多
In a paper in 1970,Brian Windley first recognised that early terrestrial and lunar anorthosites both have calcic plagioclase,and low TiO_(2)and high CaO and Al_(2)O_(3)contents.Despite these similarities,the geochemis...In a paper in 1970,Brian Windley first recognised that early terrestrial and lunar anorthosites both have calcic plagioclase,and low TiO_(2)and high CaO and Al_(2)O_(3)contents.Despite these similarities,the geochemistry of early terrestrial and lunar anorthosites has not been rigorously compared and contrasted.To this end,we compiled 425 analyses from 212 early terrestrial anorthosite occurrences and 306 analyses from 16 lunar anorthosite occurrences.This was supplemented by a compilation of plagioclase anorthite(An)contents and pyroxene Mg#from early terrestrial and lunar anorthosites.Early terrestrial anorthosites have lower whole-rock An contents but similar Mg#to lunar anorthosites.The CaO contents of lunar anorthosites are higher than those of early terrestrial anorthosites for a given MgO and Al_(2)O_(3)content,early terrestrial anorthosites have higher SiO_(2)contents than lunar anorthosites at a given MgO content,and lunar anorthosites have higher Eu/Eu*anomaly ratios yet broadly similar La/Yb and Nd/Sm ratios than early terrestrial anorthosites.Some early terrestrial anorthosites have less fractionated chondrite-normalised rare earth element(REE)patterns and less prominent positive Eu anomalies than lunar anorthosites.Lunar anorthosites have higher plagioclase An contents,yet a similar range of pyroxene Mg#compared to their early terrestrial counterparts.Some early terrestrial anorthosites are more fractionated than some lunar anorthosites.Our interpretations imply that most early terrestrial anorthosites crystallised from basaltic parental magmas that were generated by high-degree partial melting of sub-arc asthenosphere mantle wedge sources that were hydrated by slab-derived fluids,with the remainder being associated with mid-ocean ridge and mantle plume settings.Some of the arc-related early terrestrial anorthosites were influenced by crustal contamination.In addition,early terrestrial anorthosites originated from partial melting of the mantle at various depths with variable garnet residua,whereas lunar anorthosites formed without any significant garnet residua.Lower plagioclase CaO contents and pyroxene Mg#in early terrestrial anorthosites can be explained by higher proportions of clinopyroxene and olivine fractionation in terrestrial magma chambers than in the lunar magma ocean where orthopyroxene and olivine fractionation occurred.Low TiO_(2)contents in both terrestrial and lunar anorthosites reflect rutile and/or ilmenite fractionation.展开更多
文摘The modern‘Penrose’definition of ophiolites is based largely on the Troodos complex of Cyprus,which contains a spectacular and well-exposed sheeted dike complex in which dike intrudes dike without intermediate screens of
文摘Understanding crust-mantle recycling through time,especially into the Archean,is crucial for understanding how the crust has grown from the mantle,and in turn how crustal material returned to the mantle alters the mantle reservoir.Recycling of crustal material,such as C-H-O-NS-P are especially important for understanding how processes such as subduction,melting,volcanism,and the release of volatiles have regulated climate and life on Earth over billions of years.
基金This work is sponsored by the Major Program in the Ninth-five Year Plan, National Natural Science Foundation of China （No.498894190 - 4）.
文摘The analysis of strata between wells is fundamental in the study of oil and gas reservoirs. Automatic analysis of strata between wells, based on stratigraphic division of well logs, is realized using computer techniques. We use a technique of dynamic waveform matching to build cross-well stratigraphic correlation relationships and automatically draw a path diagram of the cross-well stratigraphic contrast through piecewise line fitting, log character extraction, match cost calculation, and etc.. After analyzing many structure path diagrams between wells, 30 path patterns for normal faults, reverse faults, unconformities, synsedimentary faults, listric faults, pinch-outs, and so on were summarized and the path diagram patterns and correlation conceptions are presented. The application analysis in Dagang Oil Field shows that this method is effective.
文摘In a paper in 1970,Brian Windley first recognised that early terrestrial and lunar anorthosites both have calcic plagioclase,and low TiO_(2)and high CaO and Al_(2)O_(3)contents.Despite these similarities,the geochemistry of early terrestrial and lunar anorthosites has not been rigorously compared and contrasted.To this end,we compiled 425 analyses from 212 early terrestrial anorthosite occurrences and 306 analyses from 16 lunar anorthosite occurrences.This was supplemented by a compilation of plagioclase anorthite(An)contents and pyroxene Mg#from early terrestrial and lunar anorthosites.Early terrestrial anorthosites have lower whole-rock An contents but similar Mg#to lunar anorthosites.The CaO contents of lunar anorthosites are higher than those of early terrestrial anorthosites for a given MgO and Al_(2)O_(3)content,early terrestrial anorthosites have higher SiO_(2)contents than lunar anorthosites at a given MgO content,and lunar anorthosites have higher Eu/Eu*anomaly ratios yet broadly similar La/Yb and Nd/Sm ratios than early terrestrial anorthosites.Some early terrestrial anorthosites have less fractionated chondrite-normalised rare earth element(REE)patterns and less prominent positive Eu anomalies than lunar anorthosites.Lunar anorthosites have higher plagioclase An contents,yet a similar range of pyroxene Mg#compared to their early terrestrial counterparts.Some early terrestrial anorthosites are more fractionated than some lunar anorthosites.Our interpretations imply that most early terrestrial anorthosites crystallised from basaltic parental magmas that were generated by high-degree partial melting of sub-arc asthenosphere mantle wedge sources that were hydrated by slab-derived fluids,with the remainder being associated with mid-ocean ridge and mantle plume settings.Some of the arc-related early terrestrial anorthosites were influenced by crustal contamination.In addition,early terrestrial anorthosites originated from partial melting of the mantle at various depths with variable garnet residua,whereas lunar anorthosites formed without any significant garnet residua.Lower plagioclase CaO contents and pyroxene Mg#in early terrestrial anorthosites can be explained by higher proportions of clinopyroxene and olivine fractionation in terrestrial magma chambers than in the lunar magma ocean where orthopyroxene and olivine fractionation occurred.Low TiO_(2)contents in both terrestrial and lunar anorthosites reflect rutile and/or ilmenite fractionation.
