Late Quaternary Paleoclimatic Change in the Ulleung Basin,East Sea,Korea

Paleoclimatic changes in the late Quaternary sediments deposited in the East Sea were analyzed by studying diatoms. A total of 95 species belonging to 47 genera were identified from the Core02GHP-02 of the Ulleung Basin in the East Sea, Korea. In the Core 02GHP-02, U-Oki（169–181 cm; 9.3 ka）, AT（464–465.5 cm; 22 ka） and U–Ym（556–559 cm; 33 ka） tephra layers were recognized. The chronological divisions of 02GHP-02 may be correlated with the climatic changes from the glacial interval（730–620 cm; MIS3）, to interstadial（620–500 cm; MIS3）, to the last glacial maximum（500–390 cm; MIS 2）, to the deglaciation（390–290 cm; MIS 2）, to the late glacial（290–190 cm; MIS 1）, and to the Holocene（190–10 cm; MIS 1）. It is speculated that diatoms were rarely found during the glacial interval when the 02GHP-02 core was deposited; during the interstadial（MIS 3） and deglaciation, a mixture of warm-water and cold-water species were found. In particular, Fragilariopsis doliolus seems to have appeared in the East Sea after 8 ka BP. In the lower layers of the Holocene deposits, cold-water species such as Neodenticula seminae were frequently found, while in the upper layers, warm-water species such as Hemidiscus cuneiformis were found in relatively large abundance. Therefore, the findings indicate that the climate became warmer during the transition from the lower layer to the upper layer of the Holocene deposits.

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.

Holocene Environmental Climatic Changes Based on Palynofacies and Organic Geochemical Analyses from an Inland Pond at Altitude in Southern Brazil

This paper focuses on the interpretations in the analyses of palynofacies and organic geochemistry carried out on a sedimentary profile covering 9542 cal yr BP from a pond located at the mining district from Ametista do Sul, southernmost Brazil. The hydrological isolation renders this pond, located on a hilltop, highly sensitive to climatic change because the water entering in the system is subsidized exclusively by the rainfall. The main goal of this study is to establish relationships between the sedimentary organic record and climatic fluctuations in the Holocene, trying to correlate the alterations in the particulate organic matter with regional climatic changes or perhaps even events on a global scale. Fluctuations in water depth are inferred from the frequency of the autochthonous elements (algae), which predominate in the basal intervals, but tend to decrease progressively toward the top, when begining to alternate periods of high and low frequency with the parautochthonous (spores) and allochthonous (pollen grains) elements, due to changes in the patterns of moisture. Pseudoschizaea seems to have a closer relationship with the spores than with all other algae and can serve as a biological marker of transitional intervals or have some role in the successional process of vegetation. The variety of spores of ferns and pollen grains on the topmost interval indicates increased vegetal diversity, and is probably related to the process of successional evolution of the area. An increased rainfall event detected between 8.6 to 7.4 ka yr BP can be responsible for the beginning of the process of water accumulation in the gossan and sedimentation of the pond and can be related with the “Bond Events”. The saturation level of the pond, in turn, remained relatively constant until 6.8 ka yr BP, when changes in the patterns of moisture make the environment drier and resulted in an intermittent pattern of water depth, currently existing on the site.

Surface textures of quartz grains from a core at the Prydz Bay,Antarctica

In this paper, shapes and surface textures of quartz grains in 13 layers of a core (NP95 1) collected from a continental slope at the Antarctic Prydz Bay were quantitatively and statistically analyzed. The quartz grain surfaces exhibit the characteristics caused by intense glaciation and a weaker chemical solution precipitation, indicating the sediments are mainly morainic debris under a low energy marine environment. The obtained quantitatively statistical results of the assemblages of surface textures caused by the chemical solution precipitation are well correlated to the analytical results of micropaleontologic analysis and can be used to better explain the changes of sedimentary environment and paleoclimate occurred in the marine zone concerned.