The quantitative analysis of sediment sources in a sink is an important scientific topic and challenge in provenance research.The characteristics of heavy minerals,combined with the geochemical constituents of detrita...The quantitative analysis of sediment sources in a sink is an important scientific topic and challenge in provenance research.The characteristics of heavy minerals,combined with the geochemical constituents of detrital grains,provide a reliable provenance-tracing approach.We developed a mineral identification method to analyze the multiple grain-size fraction of sediments,from which the elemental geochemistry of hornblende was used to compare the characteristics of sediments from the Huaihe River and Huanghe(Yellow)River in eastern China.Elements that were statistically identified as being able to discriminate sediment provenance were employed to perform a quantitative analysis of the sources of sediments of the abandoned Huanghe River.Results reveal that the Huaihe River is characterized by a high amphibole content of>60%and that the Huanghe and abandoned Huanghe rivers have greater abundances of limonite and carbonate minerals compared with those of the Huaihe River.The contents of trace elements and rare earth elements in hornblende show that the sediments of the abandoned Huanghe River are similar to those of the Huanghe River but different from those of the Huaihe River.Furthermore,chemical mass balance was used to calculate the relative contributions of different provenances of sediment from the abandoned Huanghe River,and nine trace elements of hornblende were identified as discriminators of provenance.Approximately 2%of the hornblende in the abandoned Huanghe River is derived from the Huaihe River and 98%from the Huanghe River.Considering the proportion of hornblende in the total sediment,it is inferred that the contribution of Huaihe River sediment to the abandoned Huanghe River is approximately 0.5%.This study shows that mineral analysis using multiple grain-size fractions(within the wide range of 1Φto 6Φ)with assessment in elemental geochemistry of hornblende can characterize the provenance of fluvial material in coastal zones.展开更多
Heavy mineral petrographic and geochemical compositions (major and trace/rare earth elements)?of sandstones obtained from the Oligocene-Miocene Ogwashi-Asaba Formation, Niger Delta were studied to determine their prov...Heavy mineral petrographic and geochemical compositions (major and trace/rare earth elements)?of sandstones obtained from the Oligocene-Miocene Ogwashi-Asaba Formation, Niger Delta were studied to determine their provenance, source area weathering conditions and tectonic setting. The heavy mineral suite (opaque minerals, zircon, tourmaline, and rutile) revealed that the sandstones are mineralogically mature and implied rapid disintegration and chemical decomposition of sediments mostly of recycled orogen. The sandstones were geochemically classified as Fe-sand and partly quartz arenitic. Chemical Index of Alteration and Chemical Index of Weathering values of 89.92% and 91.87% respectively suggest that the source region was predominantly felsic and was subjected to intense chemical weathering probably under tropical palaeoclimatic conditions with abundant rainfall that enhanced sediment recycling. Major element concentration discriminant plots also indicated that the sediments were derived from mixed sources (granitic, gneissic or recycled orogen) under passive margin setting. Chondrite normalized plot of the rare earth element pattern is marked by light rare earth element enrichment and negative Eu anomalies, interpreted to mean that provenance was mainly continental crustal rocks. Trace elemental ratios that are provenance diagnostic (La/Sc, Th/Sc, Cr/Th, La/Co, Th/Co, Th/Cr, Eu/Eu*, and Eu*) all point to sediments derived from felsic source and upper continental crust. The mixed provenance of the sandstones can be traced to the southwestern and southeastern Basement Complex (consisting of granites, gneisses, etc.) and sediments derived from the adjacent sedimentary basins (Anambra and Benue Trough).展开更多
The main task of provenance analysis is to determine the source of sediments and the position of parent rocks.Provenance analysis may find out the relationship between erosion districts and sediment zone,between the u...The main task of provenance analysis is to determine the source of sediments and the position of parent rocks.Provenance analysis may find out the relationship between erosion districts and sediment zone,between the uplift and the depression in the process of basin development.The authors use the method of heavy mineral clustering analysis and estimate the provenance direction of Huanghua Depression in the Paleogene Kong 2 Member.Research shows that there were five provenance areas of Kong 2 Member in Kongnan area.They are western(Shenusi),northwestern(Cangzhou),eastern(Ganhuatun),northeastern and southeastern.The main provenance areas were northwestern and western,while the southern provenance could not be ruled out.And these areas are consistent with the known provenance areas.展开更多
The present work deals with the geochemical and heavy mineral characteristics studies of sediments of Gosthani river estuary. The aim of study is to determine the provenance, establish the depositional environment and...The present work deals with the geochemical and heavy mineral characteristics studies of sediments of Gosthani river estuary. The aim of study is to determine the provenance, establish the depositional environment and spatial variability of sediment. From the study it is found that the sediment of Gosthani river contains heavy minerals that consist of Rutile, Garnet, Sillimanite, Staurolite, Monazite, Zercon, Pyroxenes, Epidote, Amphiboles and Opaques minerals. The lesser abundant heavy minerals are amphiboles, zircon, monazite, rutile, staurolite, epidote. These heavy minerals indicate that the sediments were essentially derived from metamorphic provenance varying from medium to high grade and partly from crystalline igneous rocks. Well rounded monazites come from Eastern Ghats. This is based on the occurrence of monazite in pegmatite and charnockites of Eastern Ghats. The various characters of rutile and zircon suggest that each of these minerals has a multisource. According to geochemical studies settling of organic matter is highest in areas where deposition of fine grained sediment takes place. The organic carbon is often a good index for deciphering depositional environment.展开更多
Sediment provenance studies commonly utilize isotopic signatures to resolve detrital mineral sources and routing.However,non-unique ages and geochemical characteristics across geographically distinct crystalline sourc...Sediment provenance studies commonly utilize isotopic signatures to resolve detrital mineral sources and routing.However,non-unique ages and geochemical characteristics across geographically distinct crystalline source regions can lead to significant ambiguities in mineral provenance interpretations.Such ambiguity is apparent in southern Australia’s Cenozoic Eucla Basin,which hosts world-class heavy mineral sand resources.Here,new Hf isotope data are provided from four heavy mineral prospects(N=8,n=844[N=samples,n=grains]).Zircon grain shape data are also presented for a suite of detrital Eucla Basin samples(N=22,n=35,604)and the basin’s underlying basement,the Coompana Province(N=13,n=824).The data are integrated with published detrital and non-detrital primary zircon data to investigate the efficacy of grain shape analysis to better resolve the basin’s mineral provenance.Zircon Hf isotope compositions indicate a primary Mesoproterozoic juvenile source for zircon melts(~1250-1000 Ma,-2.5<εHf>~+5)with additional contributions from a range of juvenile to evolved late Archean to Phanerozoic-aged zircon bearing magmas(-28.0<εHf>+11).U-Pb geochronology and Hf isotopes are incapable of differentiating Mesoproterozoic-aged source rocks bounding the region for the majority of heavy mineral deposits analyzed as potential sources express overlapping crystallization ages and similarities in Hf-isotope characteristics.However,distinct zircon grain shapes(i.e.,perimeter,major axis and circularity)facilitate improved differentiation across these Mesoproterozoic sources.Filtering of U-Pb age,Hf isotope and shape data implicate the underlying Madura and Coompana provinces as dominant sediment sources for Eucla Basin detritus aged~1400-1000 Ma.The lack of direct sediment pathways between the underlying basement provinces and placer sediments analyzed demonstrates the significance of zircon reworking from intermediate sedimentary basins in the formation of the economically significant Eucla Basin beach placers.Zircon grain shape represents a cheaply acquired and readily incorporated grain characteristic that can enhance provenance investigations.展开更多
Based on the analysis of heavy mineral assemblages in Cenozoic southwestern Qaidam Basin, we found that different areas have variable heavy mineral assemblage characteristics, which suggested that there were two sourc...Based on the analysis of heavy mineral assemblages in Cenozoic southwestern Qaidam Basin, we found that different areas have variable heavy mineral assemblage characteristics, which suggested that there were two source areas—the Altyn Mountains and the Qimen Tagh-East Kunlun Mountains. In Ganchaigou-Shizigou-Huatugou(Area A), which was mainly source from the Altyn Mountains, its heavy minerals were mainly composed of zircon, Ti-oxides, and wollastonite in the Paleoceneearly Eocene and mainly of unstable minerals, especially amphibole, in the middle Eocene-Oligene. Since the late OligoceneMiocene, the heavy minerals were still mainly unstable minerals, but the content of epidote increased and the content of amphibole decreased. In Qigequan-Hongliuquan(Area B), which was the mixed source from the Altyn Mountains and the Qimen Tagh-East Kunlun Mountains, its heavy minerals were mainly garnet, epidote, and amphibole. The source of LücaotanDongchaishan-Kunbei(Area C) was mainly from the Qimen Tagh-East Kunlun Mountains, heavy minerals in the sediments in Area C were mainly zircon and Ti-oxides in Paleogene and garnet, epidote, and amphibole in Neogene. In Yuejin-Youshashan(Area D), where the stable minerals and unstable minerals were present simultaneously, the heavy mineral assemblages was controlled by multi-direction source. The variation of heavy mineral assemblages in southwestern Qaidam Basin shows that Altyn Mountains was of low-lying topographic relief in Paleocene-early Eocene, and the rapid uplift of Altyn Mountains started from the middle Eocene. In Paleogene, the Altyn Tagh Fault had a slow strike-slip velocity, but the strike-slip velocity increased greatly since the late Oligocene, leading to a strike-slip displacement above 300 km since Neogene. Meanwhile, the Qimen Tagh-East Kunlun fault zone was under a stable tectonic stage in Paleogene with the Qimen Tagh Mountain being lowlying hills; since the late Oligocene, the fault zone started to activate and the Qimen Tagh Mountain began to uplift rapidly.展开更多
Based on the data of outcrops, seismic sections, thin sections, heavy mineral assemblages and detrital zircon U-Pb dating, the sedimentary characteristics, lake level fluctuation and provenance characteristics of the ...Based on the data of outcrops, seismic sections, thin sections, heavy mineral assemblages and detrital zircon U-Pb dating, the sedimentary characteristics, lake level fluctuation and provenance characteristics of the Middle Jurassic Lianggaoshan Formation(J_(2)l) in eastern Sichuan Basin, SW China, were investigated to reveal the control of tectonic movements of the surrounding orogenic belts on the sedimentary systems. The J_(2)lmainly developed a delta–lake sedimentary system, which contained a complete third-order sequence that was subdivided into four lake level up-down cycles(fourth-order sequence).The lake basins of cycles Ⅰ and Ⅱ were mainly distributed in eastern Sichuan Basin, while the lake basins of cycles Ⅲ and Ⅳ migrated to central Sichuan Basin, resulting in the significant difference in sedimentary characteristics between the north and the south of eastern Sichuan Basin. The provenance analysis shows that there were three types of provenances for J_(2)l. Specifically, the parent rocks of Type Ⅰ were mainly acidic igneous rocks and from the proximal northern margin of the Yangtze Plate;the parent rocks of Type Ⅱ were intermediate-acid igneous rocks and metamorphic rocks and from the central parts of the southern and northern Qinling orogenic belts;the parent rocks of Type Ⅲ were mainly metamorphic rocks followed by intermediate–acid igneous rocks, and from the North Daba Mountain area. It is recognized from the changes of sedimentary system and provenance characteristics that the sedimentary evolution of J_(2)lin eastern Sichuan Basin was controlled by the tectonic compression of the Qinling orogenic belt. In the early stage, the lake basin was restricted to the east of the study area, and Type Ⅰ provenance was dominant. With the intensifying north-south compression of the Qinling orogenic belt, the lake basin expanded rapidly and migrated northward, and the supply of Type Ⅱ provenance increased. In the middle and late stages, the uplift of the North Daba Mountain led to the lake basin migration and the gradual increase in the supply of Type Ⅲ provenance.展开更多
基金Supported by the National Natural Science Foundation of China(Nos.41576057,41876092)。
文摘The quantitative analysis of sediment sources in a sink is an important scientific topic and challenge in provenance research.The characteristics of heavy minerals,combined with the geochemical constituents of detrital grains,provide a reliable provenance-tracing approach.We developed a mineral identification method to analyze the multiple grain-size fraction of sediments,from which the elemental geochemistry of hornblende was used to compare the characteristics of sediments from the Huaihe River and Huanghe(Yellow)River in eastern China.Elements that were statistically identified as being able to discriminate sediment provenance were employed to perform a quantitative analysis of the sources of sediments of the abandoned Huanghe River.Results reveal that the Huaihe River is characterized by a high amphibole content of>60%and that the Huanghe and abandoned Huanghe rivers have greater abundances of limonite and carbonate minerals compared with those of the Huaihe River.The contents of trace elements and rare earth elements in hornblende show that the sediments of the abandoned Huanghe River are similar to those of the Huanghe River but different from those of the Huaihe River.Furthermore,chemical mass balance was used to calculate the relative contributions of different provenances of sediment from the abandoned Huanghe River,and nine trace elements of hornblende were identified as discriminators of provenance.Approximately 2%of the hornblende in the abandoned Huanghe River is derived from the Huaihe River and 98%from the Huanghe River.Considering the proportion of hornblende in the total sediment,it is inferred that the contribution of Huaihe River sediment to the abandoned Huanghe River is approximately 0.5%.This study shows that mineral analysis using multiple grain-size fractions(within the wide range of 1Φto 6Φ)with assessment in elemental geochemistry of hornblende can characterize the provenance of fluvial material in coastal zones.
文摘Heavy mineral petrographic and geochemical compositions (major and trace/rare earth elements)?of sandstones obtained from the Oligocene-Miocene Ogwashi-Asaba Formation, Niger Delta were studied to determine their provenance, source area weathering conditions and tectonic setting. The heavy mineral suite (opaque minerals, zircon, tourmaline, and rutile) revealed that the sandstones are mineralogically mature and implied rapid disintegration and chemical decomposition of sediments mostly of recycled orogen. The sandstones were geochemically classified as Fe-sand and partly quartz arenitic. Chemical Index of Alteration and Chemical Index of Weathering values of 89.92% and 91.87% respectively suggest that the source region was predominantly felsic and was subjected to intense chemical weathering probably under tropical palaeoclimatic conditions with abundant rainfall that enhanced sediment recycling. Major element concentration discriminant plots also indicated that the sediments were derived from mixed sources (granitic, gneissic or recycled orogen) under passive margin setting. Chondrite normalized plot of the rare earth element pattern is marked by light rare earth element enrichment and negative Eu anomalies, interpreted to mean that provenance was mainly continental crustal rocks. Trace elemental ratios that are provenance diagnostic (La/Sc, Th/Sc, Cr/Th, La/Co, Th/Co, Th/Cr, Eu/Eu*, and Eu*) all point to sediments derived from felsic source and upper continental crust. The mixed provenance of the sandstones can be traced to the southwestern and southeastern Basement Complex (consisting of granites, gneisses, etc.) and sediments derived from the adjacent sedimentary basins (Anambra and Benue Trough).
基金Supported by Project of Dagang Branch of Petroleum Group Company Ltd,CNPC No TJDG-JZHT-2005-JSFW-0000-00339
文摘The main task of provenance analysis is to determine the source of sediments and the position of parent rocks.Provenance analysis may find out the relationship between erosion districts and sediment zone,between the uplift and the depression in the process of basin development.The authors use the method of heavy mineral clustering analysis and estimate the provenance direction of Huanghua Depression in the Paleogene Kong 2 Member.Research shows that there were five provenance areas of Kong 2 Member in Kongnan area.They are western(Shenusi),northwestern(Cangzhou),eastern(Ganhuatun),northeastern and southeastern.The main provenance areas were northwestern and western,while the southern provenance could not be ruled out.And these areas are consistent with the known provenance areas.
文摘The present work deals with the geochemical and heavy mineral characteristics studies of sediments of Gosthani river estuary. The aim of study is to determine the provenance, establish the depositional environment and spatial variability of sediment. From the study it is found that the sediment of Gosthani river contains heavy minerals that consist of Rutile, Garnet, Sillimanite, Staurolite, Monazite, Zercon, Pyroxenes, Epidote, Amphiboles and Opaques minerals. The lesser abundant heavy minerals are amphiboles, zircon, monazite, rutile, staurolite, epidote. These heavy minerals indicate that the sediments were essentially derived from metamorphic provenance varying from medium to high grade and partly from crystalline igneous rocks. Well rounded monazites come from Eastern Ghats. This is based on the occurrence of monazite in pegmatite and charnockites of Eastern Ghats. The various characters of rutile and zircon suggest that each of these minerals has a multisource. According to geochemical studies settling of organic matter is highest in areas where deposition of fine grained sediment takes place. The organic carbon is often a good index for deciphering depositional environment.
文摘Sediment provenance studies commonly utilize isotopic signatures to resolve detrital mineral sources and routing.However,non-unique ages and geochemical characteristics across geographically distinct crystalline source regions can lead to significant ambiguities in mineral provenance interpretations.Such ambiguity is apparent in southern Australia’s Cenozoic Eucla Basin,which hosts world-class heavy mineral sand resources.Here,new Hf isotope data are provided from four heavy mineral prospects(N=8,n=844[N=samples,n=grains]).Zircon grain shape data are also presented for a suite of detrital Eucla Basin samples(N=22,n=35,604)and the basin’s underlying basement,the Coompana Province(N=13,n=824).The data are integrated with published detrital and non-detrital primary zircon data to investigate the efficacy of grain shape analysis to better resolve the basin’s mineral provenance.Zircon Hf isotope compositions indicate a primary Mesoproterozoic juvenile source for zircon melts(~1250-1000 Ma,-2.5<εHf>~+5)with additional contributions from a range of juvenile to evolved late Archean to Phanerozoic-aged zircon bearing magmas(-28.0<εHf>+11).U-Pb geochronology and Hf isotopes are incapable of differentiating Mesoproterozoic-aged source rocks bounding the region for the majority of heavy mineral deposits analyzed as potential sources express overlapping crystallization ages and similarities in Hf-isotope characteristics.However,distinct zircon grain shapes(i.e.,perimeter,major axis and circularity)facilitate improved differentiation across these Mesoproterozoic sources.Filtering of U-Pb age,Hf isotope and shape data implicate the underlying Madura and Coompana provinces as dominant sediment sources for Eucla Basin detritus aged~1400-1000 Ma.The lack of direct sediment pathways between the underlying basement provinces and placer sediments analyzed demonstrates the significance of zircon reworking from intermediate sedimentary basins in the formation of the economically significant Eucla Basin beach placers.Zircon grain shape represents a cheaply acquired and readily incorporated grain characteristic that can enhance provenance investigations.
基金supported by National S&T Major Project(Grant No.2011ZX05009-001)
文摘Based on the analysis of heavy mineral assemblages in Cenozoic southwestern Qaidam Basin, we found that different areas have variable heavy mineral assemblage characteristics, which suggested that there were two source areas—the Altyn Mountains and the Qimen Tagh-East Kunlun Mountains. In Ganchaigou-Shizigou-Huatugou(Area A), which was mainly source from the Altyn Mountains, its heavy minerals were mainly composed of zircon, Ti-oxides, and wollastonite in the Paleoceneearly Eocene and mainly of unstable minerals, especially amphibole, in the middle Eocene-Oligene. Since the late OligoceneMiocene, the heavy minerals were still mainly unstable minerals, but the content of epidote increased and the content of amphibole decreased. In Qigequan-Hongliuquan(Area B), which was the mixed source from the Altyn Mountains and the Qimen Tagh-East Kunlun Mountains, its heavy minerals were mainly garnet, epidote, and amphibole. The source of LücaotanDongchaishan-Kunbei(Area C) was mainly from the Qimen Tagh-East Kunlun Mountains, heavy minerals in the sediments in Area C were mainly zircon and Ti-oxides in Paleogene and garnet, epidote, and amphibole in Neogene. In Yuejin-Youshashan(Area D), where the stable minerals and unstable minerals were present simultaneously, the heavy mineral assemblages was controlled by multi-direction source. The variation of heavy mineral assemblages in southwestern Qaidam Basin shows that Altyn Mountains was of low-lying topographic relief in Paleocene-early Eocene, and the rapid uplift of Altyn Mountains started from the middle Eocene. In Paleogene, the Altyn Tagh Fault had a slow strike-slip velocity, but the strike-slip velocity increased greatly since the late Oligocene, leading to a strike-slip displacement above 300 km since Neogene. Meanwhile, the Qimen Tagh-East Kunlun fault zone was under a stable tectonic stage in Paleogene with the Qimen Tagh Mountain being lowlying hills; since the late Oligocene, the fault zone started to activate and the Qimen Tagh Mountain began to uplift rapidly.
基金Supported by the Scientific Research and Technology Development Project of PetroChina (2021DJ04,2021DJ0401)。
文摘Based on the data of outcrops, seismic sections, thin sections, heavy mineral assemblages and detrital zircon U-Pb dating, the sedimentary characteristics, lake level fluctuation and provenance characteristics of the Middle Jurassic Lianggaoshan Formation(J_(2)l) in eastern Sichuan Basin, SW China, were investigated to reveal the control of tectonic movements of the surrounding orogenic belts on the sedimentary systems. The J_(2)lmainly developed a delta–lake sedimentary system, which contained a complete third-order sequence that was subdivided into four lake level up-down cycles(fourth-order sequence).The lake basins of cycles Ⅰ and Ⅱ were mainly distributed in eastern Sichuan Basin, while the lake basins of cycles Ⅲ and Ⅳ migrated to central Sichuan Basin, resulting in the significant difference in sedimentary characteristics between the north and the south of eastern Sichuan Basin. The provenance analysis shows that there were three types of provenances for J_(2)l. Specifically, the parent rocks of Type Ⅰ were mainly acidic igneous rocks and from the proximal northern margin of the Yangtze Plate;the parent rocks of Type Ⅱ were intermediate-acid igneous rocks and metamorphic rocks and from the central parts of the southern and northern Qinling orogenic belts;the parent rocks of Type Ⅲ were mainly metamorphic rocks followed by intermediate–acid igneous rocks, and from the North Daba Mountain area. It is recognized from the changes of sedimentary system and provenance characteristics that the sedimentary evolution of J_(2)lin eastern Sichuan Basin was controlled by the tectonic compression of the Qinling orogenic belt. In the early stage, the lake basin was restricted to the east of the study area, and Type Ⅰ provenance was dominant. With the intensifying north-south compression of the Qinling orogenic belt, the lake basin expanded rapidly and migrated northward, and the supply of Type Ⅱ provenance increased. In the middle and late stages, the uplift of the North Daba Mountain led to the lake basin migration and the gradual increase in the supply of Type Ⅲ provenance.