Accurately determining the age of the Tuchengzi Formation has direct influence on confirming the boundary between the Jurassic and the Cretaceous systems in northern Hebei-western Liaoning, and on related geological p...Accurately determining the age of the Tuchengzi Formation has direct influence on confirming the boundary between the Jurassic and the Cretaceous systems in northern Hebei-western Liaoning, and on related geological problems in China. However, the Tuchengzi Formation mainly consists of sedi-mentary rocks, with a poor fossil record and especially lack of index fossils. The Tuchengzi Formation is also lack of the type of volcanic rocks that can provide an isotopic age. Therefore, the age of the Tuchengzi Formation has been uncertain. Based on our systematic dating of the tuff interbedded in the Tuchengzi Formation of Chengde and Jinlingsi-Yangshan basins in northern Hebei-western Liaoning, combined with the dating results of previous researchers, here we suggest that the age range of the Tuchengzi Formation in northern Hebei-western Liaoning is from 147 Ma to 136 Ma. It implied that the Tuchengzi Formation was mainly formed in the Early Cretaceous.展开更多
As one of the areas where typical late Archean crust is exposed in the Eastern Block of the North China Craton, the northern Laioning Complex consists principally of tonalitic-trondhjemitic-granodioritic （TTG） gneis...As one of the areas where typical late Archean crust is exposed in the Eastern Block of the North China Craton, the northern Laioning Complex consists principally of tonalitic-trondhjemitic-granodioritic （TTG） gneisses, massive granitoids and supracrustal rocks. The supracrustal rocks, named the Qingyuan Group, consist of interbedded amphibolite, hornblende granulite, biotite granulite and BIF. Petrological evidence indicates that the amphibolites experienced the early prograde （M1）, peak （M2） and post-peak （M3） metamorphism. The early prograde assemblage （M1） is preserved as mineral inclusions, represented by actinotite ＋ hornblende - plagioclase ＋ epidote ＋ quartz 4- sphene, within garnet porphyroblasts. The peak assemblage （M2） is indicated by garnet ＋ clinopyroxene ＋ hornblende ＋ plagioclase ＋ quartz ＋ ilmenite, which occur as major mineral phases in the rock. The post-peak assemblage （M3） is characterized by the garnet 4- quartz symplectite. The P-T pseudosections in the NCFMASHTO system constructed by using THERMOCALC define the P-T conditions of M1, M2 and M3 at 490-550 C＋（4.5 kbar, 780 810 C/7.65- 8.40 kbar and 630-670 ＋C]8.15-9.40 kbar, respectively. As a result, an anticlockwise P-T path involving isobaric cooling is inferred for the metamorphic evolution of the amphibolites. Such a P-T path suggests that the late Archean metamorphism of the northern Liaoning Complex was related to the intrusion and underplating of mantle-derived magmas. The underplating of voluminous mantle-derived magmas leading to metamorphism with an anticlockwise P-T path involving isobaric cooling may have occurred in continental magmatic arc regions, above hot spots driven by mantle plumes, or in continental rift envi- ronments. A mantle plume model is favored because this model can reasonably interpret many other geological features of late Archean basement rocks from the northern Liaoning Complex in the Eastern Block of the North China Craton as well as their anticlockwise P-T paths involving isobaric cooling.展开更多
Jianshanzi volcanic rocks at Qinghe valley in the northern Liaoning were considered belonging to Early Proterozoic Gaojiayu Formation of Liaohe Group, or to Early Cambrian Beidagou Formation of Qinghezhen Group, or Mi...Jianshanzi volcanic rocks at Qinghe valley in the northern Liaoning were considered belonging to Early Proterozoic Gaojiayu Formation of Liaohe Group, or to Early Cambrian Beidagou Formation of Qinghezhen Group, or Middle-Late Proterozoic Shenjiapu Formation-Complex of Kaiyuan Group-complex. Dating the zircons from the dacite with schistosity is 2 506 Ma in method of U-Pb (SHRIMP). This evidence indicates the rocks may be referred to Late Permian in age. Discovery of the rocks is significant to re-recognize stratigraphic property of "Liaohe Group", regional geotectonic location and revolution of orogenic zone in Qinghe valley of the northern Liaoning.展开更多
Carbonates and clastic rocks are well developed in the second-order basins of an Paleoproterozoic aulacogen in the northern Kuandian area, Liaoning Province. The carbonates cousist of two parts, the upper and the lowe...Carbonates and clastic rocks are well developed in the second-order basins of an Paleoproterozoic aulacogen in the northern Kuandian area, Liaoning Province. The carbonates cousist of two parts, the upper and the lower carbonate forma- tions. The clastic rocks occured between the two formations. Two Pb-Zn ore belts exist in both of upper and lower carbo- nate formations and are called B and A-belt respectively. Several tens of Pb-Zn ore bodies are found in A-belt. Some Pb -Zn ore bodies are apparent in vertical zoning in a sequence of Fe-Zn-Pb-Ba from the lower to the upper. Geological and geochemical researches show that the ore components in the A-belt was exhalated from the liquid source bed deeply and was precipitated in a closed second-order basins. While those in the B-belt was derived from the upper crust and was de- opsited in a normal oceanic enviornment. The second-order basins in Liaodong-Ji’nan-North Korean Peninsular aulaco- gen at the margin of the Archean craton are promising sites for looking for the deposits formed by exhalation of the liquid source bed deeply under crust.展开更多
The Ordovician Changtu Fauna is recently discovered in the Xia' ertai and Hulan Groups in northernLiaoning-central Jilin. The fauna, containing 10 genera and 14 species (including 3 new genera, 9 new speciesand an...The Ordovician Changtu Fauna is recently discovered in the Xia' ertai and Hulan Groups in northernLiaoning-central Jilin. The fauna, containing 10 genera and 14 species (including 3 new genera, 9 new speciesand an unidentified species), is closely related in evolution with the Early Cambrian Qinghezhen Fauna. Thediscovery of this fauna is significant to the study on the age of the strata, Ordovician biostratigraphy and geo-logical evolution of the tectonostratigraphical terrane on the northern margin of the Sino-Korean plate.展开更多
The Purbeck beds in Dorset, the Tuchengzi Formation in western Liaoning Liaoning Province or the Houcheng Formation in northern Hebei Province are non-marine Jurassic/Cretaceous (J/K) boundary sequences. A Czech-China...The Purbeck beds in Dorset, the Tuchengzi Formation in western Liaoning Liaoning Province or the Houcheng Formation in northern Hebei Province are non-marine Jurassic/Cretaceous (J/K) boundary sequences. A Czech-China Inter-Governmental S&T Cooperation Project has been carried out to search for the non-marine J/K boundary in northern China and making international correlation with the Purbeck beds in southern England. The combination of palaeomagnetism and biostratigraphy in northern China and southern England localities proves that these distant places had similar climatic conditions and the same fauna during the Late Jurassic and Early Cretaceous. A preliminary joint research has shown a fruitful result in searching for the non-marine J/K boundary in northern China.展开更多
For lack of reliable isotopic chronological data, the metamorphic rock series in the Faku region of northern Liaoning has long been regarded as the platform basement. Recent studies reveal that these deformed and meta...For lack of reliable isotopic chronological data, the metamorphic rock series in the Faku region of northern Liaoning has long been regarded as the platform basement. Recent studies reveal that these deformed and metamorphosed rocks, with a variety of protoliths of plutonic intrusions and supracrustal volcanic and sedimentary rocks, were genetically related to later ductile shearing events, and they, together with the syntectonic intrusions, constituted the large-scale Faku tectonites. In this paper, we report new 40Ar/39Ar data on hornblende, biotite, and K-feldspar from typical granitic mylonites in this suite of tectonites. The plateau age 256 Ma of FK53 hornblende and the high-temperature plateau age 262 Ma of Fk51-1 biotite should rep- resent the cooling ages when the granites, formed as a result of Paleozoic oceanic crustal sub- duction beneath the continental crust or collision of multiple micro-continental blocks, were ex- humed into shallow crustal levels. The plateau age 231 Ma of FK51-1 boitite and the apparent age 227 Ma of Fk51-2 K-feldspar are interpreted to record the time of ductile deformation occur- ring under greenschist facies conditions, i.e. the formation age of the Faku tectonites, while the age gradient from 197 Ma to 220 Ma of Fk51-2 K-feldspar probably record the subsequent stable uplift-cooling process. The tectonic exhumation event indicated by the plateau age 180 Ma of Fk51-2 K-feldspar may be associated with the onset of paleo-Pacific subduction beneath the North China plate. In addition, the U-Pb dating of FK54 zircon from later-intruded granite yields the age of crystallization of this super-unit intrusion at 159 Ma, thus establishing an upper limit for the formation age of the Faku tectonites, while the plateau age 125 Ma of Fk54 K-feldspar most likely corresponds to the rapid cooling and tectonic denudation event associated with the final collision between the Siberian plate and the North China plate. These isotopic ages provide im- portant geochronological constraints for re-evaluating the tectonic essence of the Faku Faulted Convex and ascertaining the suturing boundary between the North China Platform and the Xingmeng Fold System.展开更多
基于河流环境与生物指标,构建了适用于以农田和城镇等土地利用格局为主的平原地区河流健康综合评价指数(River health comprehensive assessment index,RHCAI),该指数主要由河流水文、河流形态、河岸带状况、水体理化参数以及水生生物5...基于河流环境与生物指标,构建了适用于以农田和城镇等土地利用格局为主的平原地区河流健康综合评价指数(River health comprehensive assessment index,RHCAI),该指数主要由河流水文、河流形态、河岸带状况、水体理化参数以及水生生物5大类指标构成.考虑到生物因子对河流干扰的敏感性和准确性较高,利用层次分析法适当提高了生物指标的权重.以辽北地区辽河、浑河及其支流为例,利用RHCAI对其健康状况进行了评价,结果表明,该区域河流的健康状态处于"一般"到"亚健康"水平,在被评价河流中,卧龙湖入湖河流的得分最高,接近"健康"水平,而北沙河、蒲河、柳河与东马莲河的健康状态相对较差.河流是淡水资源的重要载体,对其健康状态的科学评价可以为河流的生态修复、水资源的合理开发利用及流域的可持续发展决策提供重要的科学依据和有益借鉴.展开更多
基金Supported by National Natural Science Foundation of China (Grant No. 90714010)
文摘Accurately determining the age of the Tuchengzi Formation has direct influence on confirming the boundary between the Jurassic and the Cretaceous systems in northern Hebei-western Liaoning, and on related geological problems in China. However, the Tuchengzi Formation mainly consists of sedi-mentary rocks, with a poor fossil record and especially lack of index fossils. The Tuchengzi Formation is also lack of the type of volcanic rocks that can provide an isotopic age. Therefore, the age of the Tuchengzi Formation has been uncertain. Based on our systematic dating of the tuff interbedded in the Tuchengzi Formation of Chengde and Jinlingsi-Yangshan basins in northern Hebei-western Liaoning, combined with the dating results of previous researchers, here we suggest that the age range of the Tuchengzi Formation in northern Hebei-western Liaoning is from 147 Ma to 136 Ma. It implied that the Tuchengzi Formation was mainly formed in the Early Cretaceous.
基金financially funded by Chinese NSFC Grants(41190075,40730315, 40872123 and 41072152)Hong Kong RGC GRF grants(7066/ 07P and 7053/08P)
文摘As one of the areas where typical late Archean crust is exposed in the Eastern Block of the North China Craton, the northern Laioning Complex consists principally of tonalitic-trondhjemitic-granodioritic （TTG） gneisses, massive granitoids and supracrustal rocks. The supracrustal rocks, named the Qingyuan Group, consist of interbedded amphibolite, hornblende granulite, biotite granulite and BIF. Petrological evidence indicates that the amphibolites experienced the early prograde （M1）, peak （M2） and post-peak （M3） metamorphism. The early prograde assemblage （M1） is preserved as mineral inclusions, represented by actinotite ＋ hornblende - plagioclase ＋ epidote ＋ quartz 4- sphene, within garnet porphyroblasts. The peak assemblage （M2） is indicated by garnet ＋ clinopyroxene ＋ hornblende ＋ plagioclase ＋ quartz ＋ ilmenite, which occur as major mineral phases in the rock. The post-peak assemblage （M3） is characterized by the garnet 4- quartz symplectite. The P-T pseudosections in the NCFMASHTO system constructed by using THERMOCALC define the P-T conditions of M1, M2 and M3 at 490-550 C＋（4.5 kbar, 780 810 C/7.65- 8.40 kbar and 630-670 ＋C]8.15-9.40 kbar, respectively. As a result, an anticlockwise P-T path involving isobaric cooling is inferred for the metamorphic evolution of the amphibolites. Such a P-T path suggests that the late Archean metamorphism of the northern Liaoning Complex was related to the intrusion and underplating of mantle-derived magmas. The underplating of voluminous mantle-derived magmas leading to metamorphism with an anticlockwise P-T path involving isobaric cooling may have occurred in continental magmatic arc regions, above hot spots driven by mantle plumes, or in continental rift envi- ronments. A mantle plume model is favored because this model can reasonably interpret many other geological features of late Archean basement rocks from the northern Liaoning Complex in the Eastern Block of the North China Craton as well as their anticlockwise P-T paths involving isobaric cooling.
文摘Jianshanzi volcanic rocks at Qinghe valley in the northern Liaoning were considered belonging to Early Proterozoic Gaojiayu Formation of Liaohe Group, or to Early Cambrian Beidagou Formation of Qinghezhen Group, or Middle-Late Proterozoic Shenjiapu Formation-Complex of Kaiyuan Group-complex. Dating the zircons from the dacite with schistosity is 2 506 Ma in method of U-Pb (SHRIMP). This evidence indicates the rocks may be referred to Late Permian in age. Discovery of the rocks is significant to re-recognize stratigraphic property of "Liaohe Group", regional geotectonic location and revolution of orogenic zone in Qinghe valley of the northern Liaoning.
文摘Carbonates and clastic rocks are well developed in the second-order basins of an Paleoproterozoic aulacogen in the northern Kuandian area, Liaoning Province. The carbonates cousist of two parts, the upper and the lower carbonate forma- tions. The clastic rocks occured between the two formations. Two Pb-Zn ore belts exist in both of upper and lower carbo- nate formations and are called B and A-belt respectively. Several tens of Pb-Zn ore bodies are found in A-belt. Some Pb -Zn ore bodies are apparent in vertical zoning in a sequence of Fe-Zn-Pb-Ba from the lower to the upper. Geological and geochemical researches show that the ore components in the A-belt was exhalated from the liquid source bed deeply and was precipitated in a closed second-order basins. While those in the B-belt was derived from the upper crust and was de- opsited in a normal oceanic enviornment. The second-order basins in Liaodong-Ji’nan-North Korean Peninsular aulaco- gen at the margin of the Archean craton are promising sites for looking for the deposits formed by exhalation of the liquid source bed deeply under crust.
文摘The Ordovician Changtu Fauna is recently discovered in the Xia' ertai and Hulan Groups in northernLiaoning-central Jilin. The fauna, containing 10 genera and 14 species (including 3 new genera, 9 new speciesand an unidentified species), is closely related in evolution with the Early Cambrian Qinghezhen Fauna. Thediscovery of this fauna is significant to the study on the age of the strata, Ordovician biostratigraphy and geo-logical evolution of the tectonostratigraphical terrane on the northern margin of the Sino-Korean plate.
基金financially supported by Mobility project of Czech Ministry of Education,Youth and Sports and Ministry of Science and Technology of the People’s Republic of China(8H17050)institutional support of Inst.Geol.Czech Acad.Sci.(RVO67985831)+3 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(XDB26000000)China-Czech 42th Inter-Governmental S&T Cooperation Project(42-3)the National Natural Science Foundation of China(41572006,41688103,41972007)UNESCO/IUGS/IGCP 679 project.
文摘The Purbeck beds in Dorset, the Tuchengzi Formation in western Liaoning Liaoning Province or the Houcheng Formation in northern Hebei Province are non-marine Jurassic/Cretaceous (J/K) boundary sequences. A Czech-China Inter-Governmental S&T Cooperation Project has been carried out to search for the non-marine J/K boundary in northern China and making international correlation with the Purbeck beds in southern England. The combination of palaeomagnetism and biostratigraphy in northern China and southern England localities proves that these distant places had similar climatic conditions and the same fauna during the Late Jurassic and Early Cretaceous. A preliminary joint research has shown a fruitful result in searching for the non-marine J/K boundary in northern China.
基金supported by the Chinese Aca demy of Sciences(Grant Nos.KZCX1-07 and KZCX3.SW-138).
文摘For lack of reliable isotopic chronological data, the metamorphic rock series in the Faku region of northern Liaoning has long been regarded as the platform basement. Recent studies reveal that these deformed and metamorphosed rocks, with a variety of protoliths of plutonic intrusions and supracrustal volcanic and sedimentary rocks, were genetically related to later ductile shearing events, and they, together with the syntectonic intrusions, constituted the large-scale Faku tectonites. In this paper, we report new 40Ar/39Ar data on hornblende, biotite, and K-feldspar from typical granitic mylonites in this suite of tectonites. The plateau age 256 Ma of FK53 hornblende and the high-temperature plateau age 262 Ma of Fk51-1 biotite should rep- resent the cooling ages when the granites, formed as a result of Paleozoic oceanic crustal sub- duction beneath the continental crust or collision of multiple micro-continental blocks, were ex- humed into shallow crustal levels. The plateau age 231 Ma of FK51-1 boitite and the apparent age 227 Ma of Fk51-2 K-feldspar are interpreted to record the time of ductile deformation occur- ring under greenschist facies conditions, i.e. the formation age of the Faku tectonites, while the age gradient from 197 Ma to 220 Ma of Fk51-2 K-feldspar probably record the subsequent stable uplift-cooling process. The tectonic exhumation event indicated by the plateau age 180 Ma of Fk51-2 K-feldspar may be associated with the onset of paleo-Pacific subduction beneath the North China plate. In addition, the U-Pb dating of FK54 zircon from later-intruded granite yields the age of crystallization of this super-unit intrusion at 159 Ma, thus establishing an upper limit for the formation age of the Faku tectonites, while the plateau age 125 Ma of Fk54 K-feldspar most likely corresponds to the rapid cooling and tectonic denudation event associated with the final collision between the Siberian plate and the North China plate. These isotopic ages provide im- portant geochronological constraints for re-evaluating the tectonic essence of the Faku Faulted Convex and ascertaining the suturing boundary between the North China Platform and the Xingmeng Fold System.
文摘基于河流环境与生物指标,构建了适用于以农田和城镇等土地利用格局为主的平原地区河流健康综合评价指数(River health comprehensive assessment index,RHCAI),该指数主要由河流水文、河流形态、河岸带状况、水体理化参数以及水生生物5大类指标构成.考虑到生物因子对河流干扰的敏感性和准确性较高,利用层次分析法适当提高了生物指标的权重.以辽北地区辽河、浑河及其支流为例,利用RHCAI对其健康状况进行了评价,结果表明,该区域河流的健康状态处于"一般"到"亚健康"水平,在被评价河流中,卧龙湖入湖河流的得分最高,接近"健康"水平,而北沙河、蒲河、柳河与东马莲河的健康状态相对较差.河流是淡水资源的重要载体,对其健康状态的科学评价可以为河流的生态修复、水资源的合理开发利用及流域的可持续发展决策提供重要的科学依据和有益借鉴.
