东北二龙湾玛珥湖32ka以来沉积序列的粒度组成特征及其古气候意义

Longgang maar area in Northern China is a sensitive region to the change of Asian summer monsoon, and also an important area to understand the dynamic mechanism of global paleoclimate and paleoenvironment changes. The grain-size and major element analyses have been carried out on the samples of the core from Erlongwan maar for reconstruction of high –resolution paleoenvironment change in Northeast China. Subsampling was done by 1cm interval for the upper 19.39m. Connecting multi-proxies (including,dry density, total organic carbon, etc.), we have acquired the following conclusions: 1、 the coarse fraction in grain size reflects the intensity of surface flow, and thus the intensity of monsoon rainfall in the region. 2、 the 19.39-m-long sediment covering the past 33ka, can be divided into 3 periods: The last glacial stage (33-18.5ka B.P.)：summer monsoon rainfall was low, temperature was minimum and climatic deteriorated. The last deglaciation (18.5-10 ka B.P.): temperature rose and surface water inflow increased. But it experienced a period, a Younger Dryas-like climatic deterioration. Holocene(10-0 ka B.P.)：summer monsoon rainfall reached maxima and varied at century scale and major millennial scale. 3、 the climatic variability in the whole Holocene is positively correlated with Atlantic ice-rafting events and there is an influence of sunspot activity in the late Holocene

The history of the Yangtze River entering sea since the last glacial maximum: a review and look forward

This review paper provides a brief review on the development of ideas in the fields of the sea level change of the ECS (East China Sea), the history of the Yangtze River entering the sea and paleochannels in the shelf of the ECS since the Last Glacial Maximum (LGM). The paper summarizes two opposite theories about the Yangtze River entering the sea during the LGM. One theory is that the Yangtze River input a lacustrine in the north of Jiangsu province which was defunct in middle Holocene, and the river was once dry. The other was that the Yangtze River still existed and entered into the Okinawa Trough during the LGM, but scholars share different opinions on which course the river ran across and which place the river input the trough. This paper concludes future work is to study the evolution of the Yangtze River and the paleoclimate and the corresponding events as a whole from the view of regional and even global change, and more attention should be paid to the study on mud sediment, the Yangtze River's response to the changes in climate and sea-level, and the channel metamorphosis.

Astronomical signals in different climate proxies from the quaternary loess-soil sequences in China

IEECAS SKLLQG

Phylogeography of the Northern Atlantic species Chondrus crispus (Gigartinales, Rhodophyta) inferred from nuclear rDNA internal transcribed spacer sequences

Eighteen isolates of the red algae Chondrus crispus were collected from Northern Atlantic sites, together with C. ocellatus, C. yendoi and C. pinnulatus from the North Pacific. The nuclear rDNA internal transcribed spacer (ITS) was sequenced and compared, spanning both the ITS regions and the 5.8S rRNA gene. Percentage of nucleotide variation for C. crispus ranged from 0.3% to 4.0%. Phylogenetic analyses were performed using maximum parsimony (MP), neighbor-joining (NJ) and minimum evolution methods. They showed that two main clades existed within the C. crispus samples examined and that suggested C. crispus had a single Atlantic origin. The clustering however did not follow the geographic origin. We hypothesized that the current distribution of C. crispus populations might be a result of three main factors: temperature boundaries, paleoclimate and paleoceanography. ITS data exhibited abundant molecular information not only for phylogeographical investigation but also for systematics studies.

海水中微量元素-碳酸钙共沉淀现象模拟：古海洋环境指标的实验研究

本文主要阐述运用稳定加液-反应系统，在实验室环境下模拟海水中方解石和文石形成时微量元素共沉淀现象，主要研究微量元素固-液体系中的迁移、转化和分配。进而在对其定量描述的前提下，研究各靶元素的共沉淀行为对各种反应条件的响应，从中提取出可以用于古海洋研究的替代性指标。所研究的微量元素和部分常量元素包括非金属元素硼和砷、碱土金属元素镁、过渡金属元素(锰、钴、镍、铜、和镉)、铀系元素(铀、钍和铅)以及钇和稀土元素。 本实验首先运用pH测试、高精度滴定分析等手段测定了实验的一些基本参数，如[H+]、碱度和[Ca2+]，根据计算获得了各碳酸体系要素，并以此为基础建立了5℃、15℃和25℃及pCO2=0.0015 atm.=0.0030atm.下的人工海水中方解石或文石的沉淀动力学方程。研究表明： 1)在各个条件下，方解石或文石的沉淀速率(R)和其在海水中过饱和度(Ω)存在很好的相关性，可基本表达为Log R=k*Log(Ω-1)+b； 2) pCO2对会严重改变海水中的碳酸钙过饱和度，进而影响相应的沉淀速率，但对方解石或文石的沉淀动力学方程没有明显影响； 3)不同温度下所得的方解石或文石各自的沉淀动力学方程存在明显差异，表明这一过程受热力学元素控制。 在方解石和文石沉淀实验中，通过人为添加各种微量元素对它们的共沉淀行为进行模拟。首先通过直接溶解稀释法结合ICP-MS或采用离线螯合系统前处理结合ICP-MS测定海水、固体样品中各靶元素的浓度。在此基础之上通过换算得出各靶元素在海水([Me]sol’n)和方解石或文石沉淀([XMe]overg)中的含量，然后 计算出单个实验中各靶元素介于碳酸钙沉淀和海水之间的分异系数。 实验中通过改变晶核类型(方解石和文石)、温度、pCO2、碳酸钙过饱和度(2-12，以方解石计)、沉淀速率和靶元素起始浓度等参数，得到在不同反应条件下各靶元素的分异系数。基于分异系数之间的差异，各靶元素在方解石和文石沉淀过程中的共沉淀行为被加以分类和界定。在方解石中Mn、Co、Ni、Pb、Th、Cd、Cu、Mg等表现为相容元素。而在文石中Mn、Co、Ni、Cd等都属不相容元素。B、As、U与其他金属离子不同的是这三种元素是以BO33-、AsO33-、UO22+等基团的形式参予共沉淀的，其中BO33-和AsO33-是替代CO32-而UO22+取代Ca2+。 进一步总结各靶元素和反应条件的关系，初步得出碳酸钙沉淀动力学机制、温度、离子半径、碳酸钙矿物的晶格结构、溶液化学组成及其变化是影响微量元素随方解石和文石共沉淀过程的重要因素，并对各靶元素共沉淀模式进行了探讨。最后我们结合实际工作主要是文献中报导的有孔虫、珊瑚等生物钙质壳体或骨架中各靶元素的结果，对比我们的实验从中提取出了一些可应用于古海洋研究的潜在替代性指标，如： 1) 海水中CO32-浓度代用指标——文石U/Ca、Cd/Ca比，方解石U/Ca比； 2) 海水pH 代用指标——文石B/Ca、As/Ca 比； 3) 氧化还原代用指标——方解石Mn/Ca 比； 4) 海水化学代用指标——方解石Co/Ca 比、U/Ca 比文石Cu/Ca、Pb/Ca 比。 5）稀土元素代用指标——方解石质载体中的YREE/Ca比。 还有几种元素组合也非常具有价值，如Mn-Co-Ni 组合、B-U 组合。此外指出了现有微量元素古海洋指标应用过程中被忽略了的一些关键性因素，如文石Mg/Ca比受到文石沉淀速率的限制、方解石Cd/Ca 比受到沉淀速率和温度的双重影响等。

MB倒转在中国黄土中的记录及海陆对比

Chinese loess preserved in northwest and north China are famous for its fine grain size, high accumulate rate and high community and can be good archives for paleoclimate and paleomagnetic variation over the later Cenozoic, with which can be correlated well between marine sediments. Major geomagnetic chrons and long term paleoclimate changes in Quaternary are successfully extracted from Chinese loess-paleosols, as well as short-term geomagnetic excursions and climate instability of high resolution. Magneticstratigraphy based on paleogeomagnetic polarity reversal recorded in Chinese loess is a basic project in loess research since decades ago. True geomagnetic records and exact location of geomagnetic reversal boundary in section is the foundation of magneticstratigraphy. Matuyama-Brunhes (MB) reversal as the youngest one still remains divarication about exact location of its boundary (MBB). L8 and S8 of Luochuan and Xifeng located in the interior of Chinese Loess Plateau(CLP) and Mangshan in southeast part of CLP are chosen to make clear some problems which include magnetic mineral, process of MB reversal, location of MBB, downward displacement scale of magnetic reversal boundary, time lag of paleoclimate record by marine and loess, new correlation between Chinese loess and marine sediments. Rock-magnetic investigations carried on L8 and S8 show that the main mineral are ferrimagnetic assemblage consists of magnetite and maghemite in Luochuan and Xifeng, and magnetite in Mangshan, which all contains little hematite belongs to antiferromagnetic phases. The main carrier of nature remanet magnetism (NRM) is detrital magnetite with pseudo-single domain. Detailed paleomagnetic investigations display that there are several rapid reversals in direction during the process of MB reversal which started at the upper part of S8 and finished at the lower part of L8, and lasted about decades of centimeters to more than 100cm correspond to about 104 years. On the assumption that MBB is located in the middle part of the layer which recorded the very reversal, 11cm is considered as the scale of downward displacement for the MBB in Chinese loess after estimation through correlation between Luochuan and Mangshan records. So this study denies the theory of large scale displacement of MBB and large scale Lock-in depth of NRM acquired from Chinese loess. Time lag of paleoclimate records in terrestrial sediments and marine sediments is considered after reassessment of correlation between low field susceptibility of Chinese loess with marine oxygen isotope in benthic foraminifera. On the basis of traditional correlation between Chinese loess and marine oxygen isotope, this study document a new scheme which correlates L8 and S8 to MIS18 and MIS19, respectively.

南海沉积物中的放射虫及其古环境意义

In this paper a systematic study of radiolarian from surface sediments of all the South China Sea (SCS) has initially been done for its deposit ecology, biogeography and paleoenvironment significance. The paleoenvironment information obtained by radiolarian analysis and other sedimentary method for core samples is also made use as the synthesis proxy for revealing the paleoenvironment changes in the SCS and the relations of it with the past globe change during last 200ka. Some results come out of this study as: 1) Radiolarian skeleton chemistry composition and skeleton morphological features were analyzed, chiefly dividing them as 15 types of basic morphological features: 2) Analysis of biogeographical feature demonstrates that the fauna in SCS obviously belonging to a transitional type of west Pacific - Indian Ocean and has a particularity of itself: 3) Tendency of radiolarian population distribution is lower in shallow continental shelf area, increasing gradually toward the abyssal region; 4) Nine character boundaries of radiolarian depth distribution in the sediments from whole the South China Sea may be recognized; 5)Two radiolarian transfer functions for paleotemperature and paleo-primary productivity in the South China Sea have also been established respectively. The equation of transfer function for winter paleotemperature has only an average estimated error of 0.18678 ℃ and the equation for paleo-primary productivity has the calculation accuracy of 85.31%; 6) Changes of radiolarian individuals, numbers of species and H(S) values in core NS93-5 show the completely different oceanic geographical circumstance and ecology structure in the Last Maximum Glacial with present; 7) The abundance variation of some raiolarian warm species and cold species indicate the changes of water masse features along with the paleoenvironment evolution, showing that this sea area clearly is controlled in 6 issues of oxygen isotopes by the cold water masses; 8) By comparative analysis of δ ~(18)O curves with GISP2;s ice core can core 17940 of the northern SCS, the occurring characters of D/O's events 1-21 and Heinrich's events H1-H6 have been revealed in this sea area by core NS93-5, which prove the existence of paleoclimatic tele-connections between the southern SCS and Arctic region since about 200ka BP.

A multi-locus phylogeny of Nectogalini shrews and influences of the paleoclimate on speciation and evolution

Nectogaline shrews are a major component of the small mammalian fauna of Europe and Asia, and are notable for their diverse ecology, including utilization of aquatic habitats. So far, molecular phylogenetic analyses including nectogaline species have been unable to infer a well-resolved, well-supported phylogeny, thus limiting the power of comparative evolutionary and ecological analyses of the group. Here, we employ Bayesian phylogenetic analyses of eight mitochondrial and three nuclear genes to infer the phylogenetic relationships of nectogaline shrews. We subsequently use this phylogeny to assess the genetic diversity within the genus Episoriculus, and determine whether adaptation to aquatic habitats evolved independently multiple times. Moreover, we both analyze the fossil record and employ Bayesian relaxed clock divergence dating analyses of DNA to assess the impact of historical global climate change on the biogeography of Nectogalini. We infer strong support for the polyphyly of the genus Episoriculus. We also find strong evidence that the ability to heavily utilize aquatic habitats evolved independently in both Neomys and Chimarrogale + Nectogale lineages. Our Bayesian molecular divergence analysis suggests that the early history of Nectogalini is characterized by a rapid radiation at the Miocene/Pliocene boundary, thus potentially explaining the lack of resolution at the base of the tree. Finally, we find evidence that nectogalines once inhabited northern latitudes, but the global cooling and desiccating events at the Miocene/Pliocene and Pliocene/Pleistocene boundaries and Pleistocene glaciation resulted in the migration of most Nectogalini lineages to their present day southern distribution. (C) 2010 Elsevier Inc. All rights reserved.