Through a combined analysis of sedimentary characteristics, C and O isotopes, Mg and Sr trace elements of a stalagmite from Heshang Cave, Hubei, with uranium-series dating, alaeo-palaeoclimatic and palaeoenvironmental...Through a combined analysis of sedimentary characteristics, C and O isotopes, Mg and Sr trace elements of a stalagmite from Heshang Cave, Hubei, with uranium-series dating, alaeo-palaeoclimatic and palaeoenvironmental information from 19.0ka to 6.9ka in the Hubei area is obtained. The Average resolution is 17a, and the local resolution is 7a. The following results are obtained: (1) from 19.0-16.6 kaBP: C and O isotope is lighter, the climate is cold and wet;(2) 16.6-11.1 kaBP: C, O isotope is a little heavy, temperature rises, rainfall is inclined to be little;(3) 11.1-10.3 kaBP: an excursion during dry and hot period responds to Younger Dryas Event;(4) 10.3-6.9 kaBP: C, O Isotope is lighter, but Mg/Sr value is bigger, which shows temperature is continuing rising and rainfall is greater. These reflect the variation tends from wet-cold climate, to dry-hot climate, and to wet-warm climate in history, and some climatic variation trends of thousand years and hundred years cycle are got.展开更多
Understanding of hydrological processes in caves is important to help us interpret paleoclimate records from speleothems. In this study, we integrated hydrogeological and hydrogeochemical properties to characterize th...Understanding of hydrological processes in caves is important to help us interpret paleoclimate records from speleothems. In this study, we integrated hydrogeological and hydrogeochemical properties to characterize the hydraulic behavior of karst waters in the Heshang Cave, Central China. Using geological and topographical analyses, we identified regional watershed boundaries and hydrogeological connections that were controlled by anticlinal geometry and faults. Water samples were collected from the Heshang Cave and potential recharge sites. Geochemical data of c（Sr^2＋）/c（Ca^2＋） and c（Mg^2＋）/c（Ca^2＋） ratios suggest that the drainage system in Heshang Cave consists of two flow paths. For vadose waters, including drip water and rimstone pool water, c（Sr^2＋）/c（Ca^2＋） ratio ranges from 0.000 6 to 0.001 1, and c（Mg^2＋）/c（Ca^2＋） ratio ranges from 0.97 to 1.1, indicating that recharge was mainly from rainfall infiltration through the overlying Cambrian dolomite stratum. In contrast, slope current and underground river waters have higher c（Sr^2＋）/c（Ca^2＋） ratios （values from 0.002 2 to 0.002 8）, and lower c（Mg2＋）/c（Ca^2＋） ratios （values from 0.50 to 0.64）. These waters show homogeneous isotopic composition （δ^18O： -7.15‰- -6.95‰; δD： -52.73‰- -51.31‰）, implying recharge of allogeneic water from the Xiaocr River via karst conduits that pass through Ordovician limestone and Cambrian dolomite stratum.展开更多
Stalagmite growth rates are usually considered to reflect changes in paleoclimate and paleoenvironment.However,how exactly growth rates are affected by climate and environment is still unclear.We launched a monitoring...Stalagmite growth rates are usually considered to reflect changes in paleoclimate and paleoenvironment.However,how exactly growth rates are affected by climate and environment is still unclear.We launched a monitoring and modeling program that lasted approximately 4 years on two active drip sites in Heshang Cave,central China.We collected comprehensive quantitative data on growth rates,cave temperature,CO2 concentration,drip rate and drip-water chemistry to better understand the relationship between stalagmite growth and cave environment.By laying out glass substrates,we successfully grew stalagmite calcite crystals with rhombic characteristics,and quantified growth rates by measuring the long and short axes of calcite crystals under a microscope.Combined with coeval environmental data,we explicitly examined the roles of cave temperature,drip rate and drip-water chemistry in controlling the micro-scale growth of stalagmite calcite.Results show that growth of stalagmite calcite crystals at two drip sites exhibited similar seasonal variations - generally faster in the summer months,at ～3 μm d-1,and slower during the late winter to early spring,at ～1.5 μm d-1.Variations in calcite growth rates were mainly determined by changes in cave temperature,with the growth rate increasing by 8.1%/°C and 6.6%/°C at the two locations.This indicates the potential use of stalagmite growth rates as a seasonal-resolution paleo-temperature proxy in some ventilated caves.On the other hand,the effect of drip rate and drip-water Ca2+ and SIC values on growth rates were not significant.展开更多
Since 2004, three excavations have been carried out at a late Pleistocene human fossil site of Huanglong Cave in Yunxi County, Hubei Province of China, which unearthed seven human teeth, dozens of stone tools, mammal ...Since 2004, three excavations have been carried out at a late Pleistocene human fossil site of Huanglong Cave in Yunxi County, Hubei Province of China, which unearthed seven human teeth, dozens of stone tools, mammal fossils and other evidence indicating human activities. During the third excavation in 2006, in the same layer as the human teeth, we found some patches of black materials embed- ded in the deposit. We doubted that this black deposit layer is the remains of burning or even human use of fire at the cave. To further explore the possibility of human fire use at the Huanglong Cave, we examined samples directly taken from the black deposit layer and compared them with samples taken from several places in the cave using three methods: micromorphology, element content determination and deposit temperature analysis. Our results indicate that the contents of carbon element in the black deposit reach 64.59%―73.29%. In contrast, contents of carbon element of the comparative samples from other parts in the cave are only 5.82%―9.49%. The micromorphology analysis of the black deposit samples reveals a plant structure like axial parenchyma, fibrocyte, uniseriate ray and vessel. High-temperature magnetic susceptibility measurements suggest that the stratum possibly underwent a high temperature in the nature. Based on these lab analyses, we are sure that the black layer in the Huanglong Cave is the remains of fire and combustion did occur in the cave 100000 years ago. Taking other evidence of human activities found in the Huanglong Cave into consideration, we believe that the evidence of fire from the Huanglong Cave was caused by the human activities of controlled use of fire.展开更多
The Rhino Cave,a Paleolithic site in Shennongjia,is the highest altitude locality of rhinoceros in the Middle-South part of China,and it is also the southernmost and the richest locality in Stephanorhinus kirchbergens...The Rhino Cave,a Paleolithic site in Shennongjia,is the highest altitude locality of rhinoceros in the Middle-South part of China,and it is also the southernmost and the richest locality in Stephanorhinus kirchbergensis fossils which include cranium,mandibles,isolated teeth and postcranials.These materials can be referred to the species Stephanorhinus kirchbergensis according to the following characters:incisorless,mandibular symphysis contracted,occiput high,subaural channel closed,with nasal and frontal horns,nasal septum partially ossified,premolars hypsodont and cheekteeth with smooth enamel surface,etc.;except its relatively shorter limb bones.In China,all the Pleistocene non-Coelodonta tandem-horned rhinoceroses were assigned to the genus Dicerorhinus in the past decades.From today's viewpoint,most of them should be included in the genus Stephanorhinus,because Dicerorhinus is quite different from Stephanorhinus in the following characters:smaller body size,generally unossified nasal septum,subaural channel open and with reduced incisors,etc.This is the first knowledge of Stephanorhinus kirchbergensis associated with Ailuropoda-Stegodon fauna,the typical Pleistocene mammalian fauna in South China.展开更多
基金In this study, field sample collection is supported and helped by associate professor Wan Junwei.professor Han Qingzhi and other people in Engineering Institute.of China University of geosciences (Wuhan). The authors would like to thank them all. This wo
文摘Through a combined analysis of sedimentary characteristics, C and O isotopes, Mg and Sr trace elements of a stalagmite from Heshang Cave, Hubei, with uranium-series dating, alaeo-palaeoclimatic and palaeoenvironmental information from 19.0ka to 6.9ka in the Hubei area is obtained. The Average resolution is 17a, and the local resolution is 7a. The following results are obtained: (1) from 19.0-16.6 kaBP: C and O isotope is lighter, the climate is cold and wet;(2) 16.6-11.1 kaBP: C, O isotope is a little heavy, temperature rises, rainfall is inclined to be little;(3) 11.1-10.3 kaBP: an excursion during dry and hot period responds to Younger Dryas Event;(4) 10.3-6.9 kaBP: C, O Isotope is lighter, but Mg/Sr value is bigger, which shows temperature is continuing rising and rainfall is greater. These reflect the variation tends from wet-cold climate, to dry-hot climate, and to wet-warm climate in history, and some climatic variation trends of thousand years and hundred years cycle are got.
基金supported by the National Natural Science Foundation of China (Nos.91125009,91325101,and 06013024)
文摘Understanding of hydrological processes in caves is important to help us interpret paleoclimate records from speleothems. In this study, we integrated hydrogeological and hydrogeochemical properties to characterize the hydraulic behavior of karst waters in the Heshang Cave, Central China. Using geological and topographical analyses, we identified regional watershed boundaries and hydrogeological connections that were controlled by anticlinal geometry and faults. Water samples were collected from the Heshang Cave and potential recharge sites. Geochemical data of c（Sr^2＋）/c（Ca^2＋） and c（Mg^2＋）/c（Ca^2＋） ratios suggest that the drainage system in Heshang Cave consists of two flow paths. For vadose waters, including drip water and rimstone pool water, c（Sr^2＋）/c（Ca^2＋） ratio ranges from 0.000 6 to 0.001 1, and c（Mg^2＋）/c（Ca^2＋） ratio ranges from 0.97 to 1.1, indicating that recharge was mainly from rainfall infiltration through the overlying Cambrian dolomite stratum. In contrast, slope current and underground river waters have higher c（Sr^2＋）/c（Ca^2＋） ratios （values from 0.002 2 to 0.002 8）, and lower c（Mg2＋）/c（Ca^2＋） ratios （values from 0.50 to 0.64）. These waters show homogeneous isotopic composition （δ^18O： -7.15‰- -6.95‰; δD： -52.73‰- -51.31‰）, implying recharge of allogeneic water from the Xiaocr River via karst conduits that pass through Ordovician limestone and Cambrian dolomite stratum.
基金supported by the National Natural Science Foundation of China(40531004 and 41072262)
文摘Stalagmite growth rates are usually considered to reflect changes in paleoclimate and paleoenvironment.However,how exactly growth rates are affected by climate and environment is still unclear.We launched a monitoring and modeling program that lasted approximately 4 years on two active drip sites in Heshang Cave,central China.We collected comprehensive quantitative data on growth rates,cave temperature,CO2 concentration,drip rate and drip-water chemistry to better understand the relationship between stalagmite growth and cave environment.By laying out glass substrates,we successfully grew stalagmite calcite crystals with rhombic characteristics,and quantified growth rates by measuring the long and short axes of calcite crystals under a microscope.Combined with coeval environmental data,we explicitly examined the roles of cave temperature,drip rate and drip-water chemistry in controlling the micro-scale growth of stalagmite calcite.Results show that growth of stalagmite calcite crystals at two drip sites exhibited similar seasonal variations - generally faster in the summer months,at ～3 μm d-1,and slower during the late winter to early spring,at ～1.5 μm d-1.Variations in calcite growth rates were mainly determined by changes in cave temperature,with the growth rate increasing by 8.1%/°C and 6.6%/°C at the two locations.This indicates the potential use of stalagmite growth rates as a seasonal-resolution paleo-temperature proxy in some ventilated caves.On the other hand,the effect of drip rate and drip-water Ca2+ and SIC values on growth rates were not significant.
基金Supported by Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. KZCX2-YW-106)National Natural Science Foundation of China (Grant No. 40772016)+1 种基金National Basic Research Program of China (Grant No. 2006CB806400)International Cooperation Program of MST of China (Grant No. 2007DFB20330)
文摘Since 2004, three excavations have been carried out at a late Pleistocene human fossil site of Huanglong Cave in Yunxi County, Hubei Province of China, which unearthed seven human teeth, dozens of stone tools, mammal fossils and other evidence indicating human activities. During the third excavation in 2006, in the same layer as the human teeth, we found some patches of black materials embed- ded in the deposit. We doubted that this black deposit layer is the remains of burning or even human use of fire at the cave. To further explore the possibility of human fire use at the Huanglong Cave, we examined samples directly taken from the black deposit layer and compared them with samples taken from several places in the cave using three methods: micromorphology, element content determination and deposit temperature analysis. Our results indicate that the contents of carbon element in the black deposit reach 64.59%―73.29%. In contrast, contents of carbon element of the comparative samples from other parts in the cave are only 5.82%―9.49%. The micromorphology analysis of the black deposit samples reveals a plant structure like axial parenchyma, fibrocyte, uniseriate ray and vessel. High-temperature magnetic susceptibility measurements suggest that the stratum possibly underwent a high temperature in the nature. Based on these lab analyses, we are sure that the black layer in the Huanglong Cave is the remains of fire and combustion did occur in the cave 100000 years ago. Taking other evidence of human activities found in the Huanglong Cave into consideration, we believe that the evidence of fire from the Huanglong Cave was caused by the human activities of controlled use of fire.
基金supported by the Major Basic Research Project (Grant No. 2006CB806400)the Special Basic Research Funds of MST of China (Grant No. 2007FY110200)the IVPP Project (Grant No. KA209508)
文摘The Rhino Cave,a Paleolithic site in Shennongjia,is the highest altitude locality of rhinoceros in the Middle-South part of China,and it is also the southernmost and the richest locality in Stephanorhinus kirchbergensis fossils which include cranium,mandibles,isolated teeth and postcranials.These materials can be referred to the species Stephanorhinus kirchbergensis according to the following characters:incisorless,mandibular symphysis contracted,occiput high,subaural channel closed,with nasal and frontal horns,nasal septum partially ossified,premolars hypsodont and cheekteeth with smooth enamel surface,etc.;except its relatively shorter limb bones.In China,all the Pleistocene non-Coelodonta tandem-horned rhinoceroses were assigned to the genus Dicerorhinus in the past decades.From today's viewpoint,most of them should be included in the genus Stephanorhinus,because Dicerorhinus is quite different from Stephanorhinus in the following characters:smaller body size,generally unossified nasal septum,subaural channel open and with reduced incisors,etc.This is the first knowledge of Stephanorhinus kirchbergensis associated with Ailuropoda-Stegodon fauna,the typical Pleistocene mammalian fauna in South China.
