Complicated responses of stalagmite δ 13C to climate change during the last glaciation from Hulu Cave,Nanjing, China

We present a record on carbon stable isotopic composition (δ ¹³C), covering 75 through 10 thousands years ago (ka B.P.), from Hulu Cave, Nanjing. The overlapping d 13C profiles are very similar in pattern and range, indicating that they mainly record climatic signal. During the last glacial-interglacial transition, the >6‰ change of δ ¹³C values implies different contributions of C3 vs. C4 type plants in soils. On millennial scale, however, the increased calcite δ ¹³C during the warm Dansgaard-Oeschger (DO) events suggests a decrease of dissolved bio-genic CO₂ when water flux rate through soil is large. This correlation between heavier d 13C and higher precipitation is consistent with our previous report on the samples’ stable oxygen isotope records (Wang et al., 2001). Comparison of coeval δ ¹³C and δ ¹⁸O of stalagmites indicates that kinetic fractionation of carbon isotope is closely related to growth rate of stalagmites. This study also shows that local vegetation changes may lag behind precipitation changes by δ700 years during the deglaciation.     

A preliminary study of natural environmental change and its impact on early Late Paleolithic people in the northeast central Korean Peninsula during Marine Istope Stage 3 (40–30k cal a bp)

We comprehensively analyzed sediments obtained from an archeological excavation. A trench sediment profile of Maedun Cave (MC), South Korea, was analyzed geoarchaeologically. Multi-proxy analyses (palynomorphs, grain size, magnetic susceptibility, animal bones and artifacts) reflected the vegetation, hydroclimate and lives of prehistoric people at Marine Isotope Stage (MIS) 3 (ca. 40–30k cal a bp ) in the early Late Paleolithic. The palynoflora consisted of pollen and non-pollen palynomorphs. Under the air-circulation system in the cave, anemophilous pollen flowed in during the day, whereas waterborne pollen and spores, and freshwater algae, were transported by flooding during the summer monsoon rainy season. Mixed conifer and deciduous broad-leaved forest with an understory of pteridophytes flourished around the north-east central Korean Peninsula during MIS 3. Freshwater algae and grass pollen records may reflect precipitation intensity. It is assumed that they had flowed in during flooding caused by high precipitation during the enhanced East Asian summer monsoon, corresponding to Dansgaard–Oeschger (D/O) events 5 and 8 of δ¹⁸O GISP2 and Hulu Cave. The prehistoric people hunted herbivorous animals in the area around MC and sheltered inside it seasonally. They also used the grains of oats growing near the dwelling as a source of food.     

Reevaluating the tectonic uplift of western Mount Carmel, Israel, since the middle Pleistocene

Reevaluation of geological and archaeological evidence from western Mount Carmel constrains its maximal tectonic uplift since the Middle Pleistocene. Tabun Cave, presently 45 m above sea level (asl), revealed human occupation from about 600 ka to 90 ka before present. The 25 m thick archaeological strata at Tabun are composed of laminated fine sand, silt and clays. Moreover, no marine deposits were found in Tabun or nearby caves. Since sea level in the last 600 ka reached a maximal of 5 to 10 m asl, Tabun Cave could not have been uplifted since then by more than 35 to 40 m, that is a maximal average rate of 58 to 67 mm/ka.     

大连骆驼山金远洞埃楚斯堪熊（Ursus etruscus）新材料及中国Ursus cf. etruscus材料的简要回顾

本文系统描述了大连骆驼山金远洞第四层（L4）出土的熊科化石材料,并简要回顾了中国的似埃楚斯堪熊（Ursus cf. etruscus）化石材料。通过系统比较,认为金远洞L4和之前中国北方早更新世被归入Ursus cf. etruscus的材料（陕西蓝田公王岭的除外）同属于一类熊类,这种熊类和欧洲的埃楚斯堪熊（U. etruscus）最为接近,但又表现出一些独特的特征,因此建立一新亚种,即东方埃楚斯堪熊（U. e. orientalis subsp. nov.）。U. e. orientalis subsp. nov.比欧洲早更新世早期的圣瓦利埃埃楚斯堪熊（U. e. saintvallierensis）更加进步,而和早更新世中期欧洲的埃楚斯堪熊指名亚种（U. e. etruscus）以及西亚的维氏埃楚斯堪熊（U. e. verescagini）演化程度近似,但个体大小明显小于这两个亚种。U. e. orientalis subsp. nov.表现出一些和棕熊（U. arctos）近似的特征,如p4后内嵴明显内偏,可能为U. arctos的祖先。U. e. orientalis subsp. nov.和中国南方的亚洲黑熊（U. thibetanus）虽然属于不同支系,但在牙齿适应和个体大小上较为近似,可能有着相似的生态位,相互之间较为排斥。这可能是U. thibetanus和U. e. orientalis subsp. nov.呈现出南北分异格局的重要原因。

     

岩溶洞穴水理化性质特征及其环境意义——以贵州织金洞为例

为揭示洞穴水地球化学特征的动态变化特征、控制因素及其环境意义,从2015年1月至2015年6月对贵州织金洞洞穴水的水化学指标进行了为期6个月的动态监测,结果表明:①织金洞洞穴水的水化学类型主要为HCO3--Ca2+-Mg2+型水,阴离子中HCO3-占84.5%以上,阳离子中Ca2+、Mg2+为优势离子;②洞穴滴水 EC、Ca2+、 Mg2+、HCO3-、SO42-浓度均大于石灰岩石裂隙水、池水相应的浓度;③洞穴水滴率、滴量、Ca2+、HCO3-以及Ca2+/HCO3-比值对气候有一定的响应,其地球化学指标具有显著的季节效应;④洞穴滴水中的EC与Ca2+离子浓度呈显著线性关系。      

南京葫芦洞石笋生长速率及其气候意义讨论

一支连续发育4?000年纹层的末次盛冰期葫芦洞石笋的年际生长速率与高分辨率δ¹⁸O曲线对比分析表明,年际生长速率在不同时间尺度上对年均温和地表有效湿度的变化有着复杂的响应关系。对该洞内持续发育3~4万年的两支单体石笋实测了33个²³⁰Th年龄,其生长曲线显示MIS 2比MIS 3阶段平均生长速率增大了40%以上。以5000年为步长的同一洞穴17支石笋生长频率支持平均生长速率的研究结果,说明在轨道尺度上较大的石笋生长速率并不完全指示较暖湿的气候条件。作者认为,年际尺度的连续生长速率是决定石笋平均生长速率的关键因素。盛冰期条件下本区洞穴内外的温差效应导致了24~14ka B.P.年际尺度的石笋连续生长。     

Comparative Analysis of Cave Strain and Borehole Bulk Strain of the Tai'an Seismic Station

Based on the cave strain observation data in 2013 at Tai'an seismic station,we use the Venedikov harmonic analysis method to calculate the cave strain measurement and phase lag of the tide factor, and qualitatively evaluate the stability of the tidal factor for observational data evaluation. At the same time, the two measurement items of the observation instrument are calculated,and the correlation strain parameters are extracted and compared. On this basis,the strain parameter time series calculation is carried out on the data quality of Taian seismic station,which is relatively stable,and the 2 sets of instruments are compared. Through the analysis, it is found that the stress field is abnormal,and the corresponding relationship between the anomaly of the stress field and the gravity field is compared and analyzed.     

Evidence of NAO control on subsurface ice accumulation in a 1200 yr old cave-ice sequence, St. Livres ice cave, Switzerland

Mid-latitude ice caves are assumed to be highly sensitive to climatic changes and thus represent a potentially interesting environmental archive. Establishing a precise chronology is, however, a prerequisite for the understanding of processes driving the cave-ice mass balance and thus allows a paleoenvironmental interpretation. At St. Livres ice cave (Jura Mountains, Switzerland), subfossil trees and organic material are abundant in the cave-ice deposit, therefore allowing the dating of individual ice layers. The dendrochronological analysis of 45 subfossil samples of Norway spruce (Picea abies (L.) Karst.) from the overhanging front of the ice outcrop as well as the dating of seven wood samples with ¹⁴C dating allowed for a reconstruction of the St. Livres cave-ice sequence and for the determination of periods of ice accumulation and ablation. Results suggest a maximal age of 1200 ± 50 ¹⁴C yr BP for the observed ice sequence and indicate the presence of four major deposition gaps dated to the 14th, 15th, mid-19th and late 19th century, which can be related with periods of positive North Atlantic Oscillation anomalies (NAO+) over the winter half-year and/or anthropogenic cave-ice abstraction. Similarly, there is evidence that periods of cave-ice accumulation as observed between AD 1877-1900 and AD 1393-1415 would correspond with phases of negative NAO indices. Cave ice represents therefore an original climate archive for the winter half-year and is complementary to other continental proxies recording preferentially summer conditions (e.g., tree rings, varves).     

Late Holocene environmental reconstruction using cave sediments from Belize

Cave sediments collected from Reflection Cave on the Vaca Plateau, Belize show variations in the δ¹³C values of their fulvic acids (FAs), which indicate periods of vegetation change caused by climatic and Maya influences during the late Holocene. The δ¹³C values range from − 27.11‰ to − 21.52‰, a shift of ∼ 5.59‰, which suggests fluctuating contributions of C₃ and C₄ plants throughout the last 2.5 ka, with C₄ plant input reflecting periods of Maya agriculture. Maya activity in the study area occurred at different intensities from ∼ 2600 cal yr BP until ∼ 1500 cal yr BP, after which agricultural practices waned as the Maya depopulated the area. These changes in plant assemblages were in response to changes in available water resources, with increased aridity leading to the eventual abandonment of agricultural areas. The Ix Chel archaeological site, located in the study area, is a highland site that would have been among the first agricultural settlements to be affected during periods of aridity. During these periods, minimal water resources would have been available in this highly karstified, well-drained area, and supplemental groundwater extraction would have been difficult due to the extreme depth of the water table.