The Sedimentary Features and Significances of Dripwater and Modern Speleothems in Xueyu Cave,Chongqing,China

Based on the continuous monthly monitoring works of the dripwater and modem speleothems in Xueyu Cave,we measured a high deposit rate of the secondary sediments.Impressively,the mean deposit rate of calcite is 5.33 mg/day,but the variation amplitude is significant during the year.Besides,the monthly variation does not coincide with the geochemical characteristics of the relevant dripwater, and a preliminary test of some hydrophilic and

Dating of Speleothems Section in Shihua Cave,Beijing

Beijing Shihua Cave is located at the northeastern part of the granite fringed Paleozoic to Mesozoic synclinal belt in Fangshan,which is face to face with the Peking Man(Homo erectus pekinensis) Relic Site.The stratigraphy sequence is composed of Majiagou Formation limestone formed before 460 Ma in Middle Ordovician.The large forms of cave began to

Oxygen and carbon isotopic characteristics of rainwater,drip water and present speleothems in a cave in Guilin area,and their environmental meanings

The studies of the oxgen and carbon isotopes of the rainwater in Guilin area, the drip water and the present carbonate deposit in Panlong cave of Guilin show that: (i) as to the general characteristics of the oxygen isotopes of the rainwater within a year and between years, the δ18O values decrease with an increase of air temperature and the rainfall, and the correlation between δ18O values and the mean monthly air temperature is much better than that between δ18O values and the rainfall, and the δ18O values of the rainwater during the summer monsoon are much smaller than those during winter monsoon; (ii) δ18O values of the drip water have a quite good correlation with the δ18O values of the rainwater in the same period; (iii) when the conditions are appropriate, δ13C can be used as an environmental proxy, that is, the smaller δ13C of speleothems is, the larger the proportion of C3 plants is and the more plentiful the rainfall is. On the contrary, C4plants may be prevailing or the environment may be a stony desert caused by climate changes or human activity.

Application of Avaatech X-ray fluorescence core-scanning in Sr/Ca analysis of speleothems

Application of X-ray fluorescence core-scanning(XRF-CS) on both marine and lake sediments has achieved remarkable results. However, its application has not been widely extended to the research on speleothems. In this study, we measure the Sr abundance and the Sr/Ca ratios of three stalagmites(two aragonite stalagmites, one calcite stalagmite) using the state-of-the-art fourth-generation Avaatech high-resolution XRF core scanner. Through comparisons among different scan paths and among different scan resolutions, as well as comparisons with inductively coupled plasma optical emission spectrometer(ICP-OES), Itrax XRF, and Artax XRF results, we confirm that the Avaatech XRF core scanner could precisely, quickly, and nondestructively analyze the high-resolution Sr abundance of speleothems. Furthermore, we combine the stalagmite δ^(18)O records to explore the paleoclimatic significance of the measured stalagmite Sr/Ca.

TIMS U-series ages of speleothems from the Tangshan caves, Nanjing

U-series ages of a set of speleothem samples from the two caves near Tangshan Town, Nanjing, determined by thermal ionization mass spectrometry (TIMS), range from older than 500 KaBP to around 20 kaBP. These dated speleothems with unequivocal stratigraphic layers in cave sediments provide basic data to establish a geochronologic sequence for the

Preliminary study on climatic signals of stable isotopes from Holocene speleothems under monsoon condition

Within the East Asian monsoon zone the change in oxygen isotope of Holocene stalagmite is mainly related to monsoon rain rather than to temperature. And carbon isotope can be taken as a comprehensive signal which contains the natural information and the information of anthropogenic activity. Isotopic analysis is also compared with the annual layer records.

Speleological Investigation of the Largest Limestone Massif in Georgia (Caucasus)

Georgia is home to multiple, widespread limestone massifs with well-developed karst areas and their associated landscape features found throughout the country. Due to geological, geomorphological, and speleological characteristics of the limestone massifs in Georgia, there are developments in classical karst processes and landforms, which contain very impressive karst features, such as dolines, caves, calcite depositions and others. For example, in Georgia, the world’s deepest caves are found, such as: Krubera-2197 m;Sarma-1830 m;Pantyukhina-1508;Ilyukhina-1275 m;Kuibyshev-1110 m, and others. Of these, Krubera Cave is currently the deepest in the world. The goal of this work is to present speleological investigation of Muradi Cave, which is developed in Racha limestone massif. Muradi Cave is unique as the fact that it contains almost all types and subtypes of speleothems and sediments recorded nowadays in the caves of the Caucasus region, and the mineral aggregates found in Muradi Cave are rare for the caves of the Caucasus region. Unlike many of the hypogene caves in the region, Murdai Cave is formed from a more traditional mechanism of speleogenesis, but the influence of tectonic activity and complex hydrologic regimes led to the development of speleothems and passage morphology less common in the region and likely from hypogenic overprinting. The primary objectives of this study of Muradi Cave included undertaking important investigation in this country, to better understand the speleogenetic processes.

Paleoclimate reconstruction during MIS5a based on a speleothem from Nerja Cave, Málaga, South Spain

Speleothems from Nerja Cave in southern Spain provide a record during interglacial period MIS5a. Period of speleothem deposition occurred from 70,000 90,000 yr ago. Oxygen (δ18O) and hydrogen (δD) isotope ratios of speleothem and fluid inclusions enable the reconstruction of climatic variability in this region of southern Spain. Fluid inclusions trapped in speleothems represent samples of drip water from which the speleothems grew. The isotopic compositions of cave dripwaters approximate average annual δ18O and δD of precipitation, therefore δ18O can be calculated from D/H of inclusion water using the MWL relationship δD = 8δ18O + 10. The measurements of the δD values of fluid-inclusion water and δ18O values from speleothems have been applied to paleoclimate reconstruction in Southern Spain indicating a colder condition than at present.

Isotopic and Petrographic Evidence as a Proxy in Paleoclimatic Reconstructions from Flowstones in Southern Spain

Changes in the morphology and mineralogy of speleothems (flowstones) clearly respond to climate-related phenomena, such as drip rate variability and temperature-modulated cave ventilation. Detailed petrographic observations have been coupled with δ18O and δ13C values. Fabrics may show changes related to variations in supersaturation, drip rate or input of detrital particles or organic compounds. Fabrics formed under relatively constant and regular drips (columnar compact, open and elongated) show similar δ18O and δ13C values, which are more negative than those of micrite and microsparite. The combination of internal microstratigraphy studies and isotopic data (δ18O and δ13C) from two flowstones collected from two caves in the north of Almeria province (SE Spain), suggest a spectrum of environmental conditions ranging from wetter to drier periods. Both records constitute a very useful tool for screening and interpreting high-resolution paleoclimate reconstructions.

Stable Carbon Isotope Variations in Cave Percolation Waters and their Implications in Four Caves of Guizhou, China

Monitoring and sampling of main plants, soil CO2, soil water, bedrock, spring water, drip water and its corresponding speleothem were performed at four cave systems of Guizhou, Southwest China, from April 2003 to May 2004, in order to understand stable carbon isotope ratios variations of dissolved inorganic Carbon （DIC） in cave percolation waters （δ13CDIC） and their implications for paleoclimate. Stable carbon isotopic compositions and ions （Ca, Mg, Sr, SO4, CI etc.） were measured for all samples. The results indicate that there are significant differences among the δ13CDIC values from inter-cave, even inter-drip of intra-cave in the four caves. The δ13CDIC values from the Liangfeng Cave （LFC） is lightest among the four caves, where vegetation type overlying the cave is primary forest dominated by tall trees with lighter average δ13C value （-29.9‰）. And there are remarkable differences in δ13CDIC values of different drip waters in the Qixing Cave （QXC） and Jiangjun Cave （JJC）, up to 6.9‰ and 7.8‰, respectively. Further analyses show that the δ13CDIC values in cave drip waters are not only controlled by vegetation biomass overlying the cave, but also hydro-geochemical processes. Therefore, accurate interpreting of δ13C recorded in speleothems cannot be guaranteed if these effects of the above mentioned factors are not taken into consideration.

Determining the Authenticity of Artifacts by Oxygen Isotope Analysis

A technique used to determine the authenticity of artifacts that compares the oxygen isotopic composition of speleothems to the carbonate included within the patina of unprovenanced artifacts is of questionable value. The unprovenanced Jehoash Inscription Tablet and James Ossuary are of potentially immense historical and cultural importance. Nevertheless, they both were rejected by workers based on the oxygen isotope technique which provided the major foundational evidence of forgery in the longest running archaeological trial in Israel. Nevertheless, both these artifacts were determined not to be forged. The initial incongruence between the oxygen isotopes of the speleothems of the Soreq cave (Israel) purported to represent the unique composition of Jerusalem rainfall, and the patina on the artifacts, can be readily explained by the accretion of materials and geo-biochemical processes expected in normal patina formation in the Jerusalem region. The patina formation involves sporadic events in disequilibrium kinetic processes that are opposed to the equilibrium formation of speleothems in a sealed cave. Moreover, 23 of 56 patina samples (41%) on well-documented ancient artifacts from Israel yielded oxygen isotope values greater or lower than the expected speleothem values of -4 δ18O ‰ [PDB] to -6 δ18O ‰ [PDB]. Thus, the speleothem-patina correlation is invalid and the applied oxygen isotopes technique for determining the authenticity of patinas on artifacts is not a useful tool in the authentication of artifacts.

The hydrologic record of karst systems: linking soil moisture to the carbon isotope signatures of soils above the Blue Spring cave system

Speleothem carbonates are precipitated continuously from inorganic carbon dissolved in seepage water infiltrating from the land surface,that reflects a mixture of atmospheric CO_2,respired soil carbon,and epikarst sources,each with distinct δ^(13)C values.To aid in deconvolving these signatures,soil samples were collected above the Blue Spring cave system in Sparta,Tennessee,USA and subjected to a series of incubation experiments,in order to constrain the correlation between CO_2respiration rates and soil moisture.This relationship is used to parameterize a simple mixing model which predicts the relationship between δ^(13)C and soil moisture in fluids infiltrating into the underlying cave system.

U-series Dating of Ganqian Cave in Guangxi and Its Anthropological Implications

From Ganqian (Tubo) Cave a total of 17 hominid teeth attributed to late Homo sapiens has been collected along with an abundance of mammalian fossils. The fossiliferous deposits are bracketed by the capping and second flowstone layers, which yielded 230 Th/ 234 U dates of ～93 and ～220 ka, marking the minimum and maximum age of the hominid teeth respectively. Two U series methods performed on two mammalian teeth gave dates in the range of 85 and 139 ka, lending support to the stratigraphic order of the depositional sequence. The results presented in this paper point to an occurrence of modern Homo sapiens in southern China much earlier than has been thought, which is supported by the dating of nearby Liujiang and Bailiandong hominid sites. Taken together, these data suggest that China should not be considered as a backwater in recent human evolution where all the previous populations were replaced.

Preliminary Studies of Speleothem in Central Asia

The Westerlies is important in linking the Northem high latitude, North Atlantic and East Asian monsoon. The location and intensity of the Westerly jet can not only control the climate of central Asia （including northwest arid China）, but also significantly influence the climate of the East Asian monsoon region. However, it remains unclear of the variability of the Westerlies in Asia on multiple timeseales and their global linkage.

Transportation characteristics of δ^(13)C in the plants-soil-bedrock-cave system in Chongqing karst area

Here we use an analytical method to determine δ^13C in local plants and organic matter in the soils above Furong cave, Chong- qing, China. We also monitored d13C in dissolved inorganic carbon （DIC） of drip water, δ^13C of active deposits under the drip waters, and the concentration of air CO2 （PCO2）. Based on these, we preliminarily studied the transportation characteristics of stable carbon isotope （^13C） in cave system of the subtropical karst area. The average δ^13C value of 27 local plant samples, which belong to 16 families, was -32% and the weighted δ^13C for surface dry biomass was -33%0. We found that for 54 soil samples collected from 5 soil profiles, δ^13C of soil organic matters was -22%o, which could be attributed to the different trans- portation rates of stable carbon isotopes during the decomposition of plants and organic matters in soils. The relatively lighter 12C tended to transfer into gaseous CO2, which made the relatively heavier ^13C concentrated in the soils. On the basis of moni- toring of DIC- δ^13C in drip waters from July 2009 to June 2010, we found that values in winter months were heavier and values in summer months were lighter in general, the reason of which was that in summer months, both the temperature and the hu- midity were comparatively higher, resulted in more CO2 with lighter δ^13C generated from organic matters decomposition and plants respiration. The average DIC- δ^13C value was -11%o, about 11%o heavier than the δ^13C of organic matters in soils, which proved that part of DIC in cave drip water was sourced from dissolution of inorganic carbonate （host rock, with heavier δ^13C. As for the δ^13C of active deposits at five drip water sites in Furong cave, they had almost the same variation with relatively light values. In other words, these active speleothems were deposited at equilibrium conditions for isotopic fractionation. These results suggest that the carbon isotopic information of speleothems could be used to track the evolution of local vegetation in certain situations.

Distributions of fatty acids in a stalagmite related to paleoclimate change at Qingjiang in Hubei,southern China

Fatty acids extracted from a subtropical stalagmite at Qingjiang in Southern China’s Hubei Province were analysed using gas chromatography-mass spectrometry. These n-alkanoic acids range from C14 to C26 in carbon number, maximizing at C16, with a second dominance at C22. In contrast to the stalagmite analysed, the overlying soils are characterized by the dominance of heavy-molecular-weight homologues (>C20). The n-fatty acids in the stalagmite were proposed to be contributed by both the soil ecosystems and the microbes harboring in the percolating water and the cave. The ratios of unsaturated to saturated n-fatty acids (C16:1i/C16:0, C18:1/C18:0) appear to show trends comparable with the oxygen isotope records of the stalagmite carbonate, with enhanced values associated with the cold episode such as Heinrich event 1. This paleoclimate-dependent record of the n-fatty acids might reflect microbial changes in physiology and activity in response to the temperature. This record shows somewhat difference from the previous paleoclimate signal extracted from n-alkanols and n-alkan-2-ones of the same stalagmite. The acid record fails to document the well-known Younger Dryas event which was effectively shown by the latter two biomarkers derived from soil ecosystems. This discrepancy might result from the changing biogeochemical impact on different lipid fractions as well as the varied organism populations in different ecosystems.

Speleothem annual layers revealed by seasonal SIMS δ^(18)O measurements

In-situ seasonalδ18O measurements of section 236.3-235.6 cm of speleothem HS4, from Qingjiang Valley of the Middle reaches of Yangtze River, China, were performed by an Secondary Ionization Mass Spectrometry （SIMS） with Oka （Chinese primary calcite standard GBW04481） and UWC-3 （international calcite standard from University of Wisconsin）. The potential of using SIMS δ18O measurements to establish speleothem time series has been explored and the differences between conventional and SIMS δ18O values have been discussed. During a 3-day period, UWC-3 δ18O has been measured on Cameca IMS δ18O Ion Microprobe Mass Spectrometer against ＂Oka＂ external standard. The measured mean value of UWC-3 （δ18OVPDB= -17.85‰±0.22‰, 1SD） matches well with its recommended value （δ18OvPDB=-17.83‰±0.08‰）, suggesting that the instrument was stable. The same method applied on HS4 produced δ18O measurements at seasonal resolution with distinct annual cycles and the total cycle number in agreement with that from Mg/Ca cycles and lamination layer counting of the same section, so it offers an alternative for accessing speleothem time series. However, compared with conventional δ18O values of HS4, SIMS δ18O values are more negative by 0.90‰ with larger seasonal variation. The main reasons might come from the mi- cro-cracks, micro-pores or liquid inclusions existing in HS4, and organic materials in the speleothem might be another factor affecting the SIMS δ18O values, indicating that to obtain reliable speleothem SIMS δ18O values, both compaction and purity of samples are crucial.

A multiple-proxy stalagmite record reveals historical deforestation in central Shandong, northern China

Evaluating anthropogenic impacts on regional vegetation changes during historical time is not only important for a better understanding of the Anthropocene but also valuable in improving the vegetation-climate models.In this study,we analyzed stable isotopes(δ^18O,δ^13C)and trace elements(Mg/Ca,Sr/Ca)of a stalagmite from Huangchao Cave in central Shandong,northern China.230Th and AMS14C dating results indicate the stalagmite deposited during 174BC and AD1810,with a hiatus between AD638 and 1102.Broad similarities of theδ^18O and trace elements in the stalagmite suggest they are reliable precipitation indexes.Theδ^13C of the stalagmite,a proxy of vegetation change,was generally consistent with local precipitation and temperature variations on a centennial-scale before the 15th century.It typically varied from–9.6‰to–6.3‰,indicating climate controlled C3 type vegetation during this period.However,a persistent and marked increasing trend in theδ^13C record was observed since the 15th century,resulting inδ^13C values from–7.7‰to–1.6‰in the next four centuries.This unprecedentedδ^13C change caused by vegetation deterioration cannot be explained by climate change but is fairly consistent with the dramatically increasing population and farmland in Shandong.We suggest that the increasing deforestation and reclamation in central Shandong began to affect vegetation in the mountain region of central Shandong since the 15th century and severely destroyed or even cleared the forest during the 16th–18th century.