中国南方第四纪红土研究进展

从红土成因、年代学研究、红土与古环境演变等方面,对中国南方第四纪红土研究进展进行了详细论述与总结,进而提出目前红土研究中存在的问题以及未来研究重点.     

萨拉乌苏河地区苦干第四纪沉积与环境问题初探

根据萨拉乌苏河若干地段的第四纪沉积记录，讨论了萨拉乌苏不可河谷的形成时代、古湖形成原因、全新世湖沼层的环境意义，晚更新世黄土与风成砂关系等总是认为萨拉乌苏河地区所经历的河流－湖泊－湖沼－河流的演化过程，均受到第四纪环境演变化规律的控制，是自然环境变迁的结果。     

中国南方红土的研究进展

中国南方的红土是晚新生代以来重要堆积物，为特定的气候环境下的产物，蕴藏着丰富的环境演化信息，为全球变化的 良好信息载体，作者对红土的成因、发育期次、年代学、古气候学、生物学、磁学性质等方面的不同观点作了较为详细的论述，从而提出了目前红土研究中存在的问题及解决的方法。     

萨拉乌苏河地区若干第四纪沉积与环境问题初探

根据萨拉乌苏河若干地段的第四纪沉积记录，讨论了萨拉乌苏河河谷的形成时代、古湖形成原因、全新世湖沼层的环境意义、晚更新世黄土与风成砂关系等问题，认为萨拉乌苏河地区所经历的河流—湖泊—湖沼—河流的演化过程，均受到第四纪环境演变规律的控制，是自然环境变迁的结果．     

皖南青弋江、水阳江地区第四纪沉积与环境变迁

本文依据野外观察、钻孔资料、孢粉分析、~（14）C测年资料及邻区地层对比,研究调查区第四纪沉积特征及地层划分,根据第四纪沉积物的资料,追溯本区自早更新世以来的古地理环境特征及其演变过程。     

青藏高原风化壳红土的沉积地球化学和矿物学特征及环境意义

对青藏高原主夷平面上分布的风化壳红土进行了沉积地球化学和矿物学方面的研究。结果表明,高原风化壳红土中细粒物质（粒径小于１ｍｍ）的粒径分布范围较广且比较均匀;红土中粘粒部分的主要化学成分为ＳｉＯ２,Ａｌ２Ｏ３和Ｆｅ２Ｏ３;粘土矿物多属于伊利石－高岭石型组合,少数属高岭石－伊利石型组合。高原风化壳红土处在红土化的初期阶段,间接反映了青藏高原古岩溶发育时期的湿热气候。     

南方红土磁化率特征及其古环境意义探讨

中国南方红土,由于沉积环境的复杂性和物质来源的多样性,其磁化率研究还存在一定的局限性和滞后性．对南方红土磁化率的研究表明,母岩和磁性颗粒物的粒度是控制红土磁化率变化的主导因素,而有机质和风化过程的存在使这种控制过程更加复杂．利用南方红土磁化率来进行古环境的重建和恢复目前争议较大,对红土形成机制及此过程中磁性矿物变化过程的深入研究将有助于解决这一争议．南方红土磁化率研究的系统化、定量化及标准剖面的建立是磁化率在南方古环境演化中起重要作用的关键所在．     

四川成都地区第四纪红土磁学特征及其环境意义

选择了关注较少,第四纪红土分布最西界——四川成都平原中的一个第四纪红土剖面作为研究对象,通过系统的环境磁学分析,结合色度和常量地球化学元素指标,探讨磁学参数的环境指示意义,探寻适用的气候代用指标.结果表明：(1)成都地区第四纪红土剖面经历了细粒亚铁磁性矿物转化分解、剖面整体呈低磁性、磁性矿物主要为反铁磁性矿物、磁性颗粒以假单畴(PSD)和多畴(MD)的粗颗粒为主.(2)剖面弱网纹层成土强度较弱、亚铁磁性矿物含量较高、磁性较强、磁性矿物粒径较细;典型网纹层成土强度较高、磁性较弱、磁性颗粒较粗.(3)剖面土壤发育序列的CIA、磁学特征的变化指示了当地气候趋于冷干,且不及同时期的长江中下游地区暖湿.(4)反映剖面反铁磁性矿物的赤铁矿、针铁矿信息的色度参数与CIA对应良好,可以作为南方地区古气候变化研究的代用指标.     

福建东南部第四纪红土沉积粒度特征及成因分析

在野外考察采样和实验分析基础上,对福建东南部若干红土剖面粒度特征及其沉积环境进行了初步研究.结果表明:1)福建东南部红土粒度组成以粉砂为主,含量65.09%～70.07%,砂含量11.90%～28.40%,粘粒6.51%～18.03%.2)粒度频率曲线以多峰为主并有明显变化,各剖面第一众数在4～71μm之间,第二众数在118～746μm之间,第三众数1μm;概率累积曲线以四段式为主.3)粒度参数总体平均粒径较粗、分选差、峰度平缓,由晚更新世早期到晚期各个粒度参数的变化趋于复杂.这些特征表明研究区红土近源水动力搬运和快速混杂堆积的特点,其后经历较强化学风化作用,晚更新世全球气候恶化对研究区红土搬运沉积过程和风化过程产生明显影响.     

福建长乐第四纪红土微量元素揭示的气候环境变化

在野外考察采样基础上,结合OSL和ESR测年确定红土沉积年代,对福建长乐(CL)红土剖面微量元素地球化学特征及指示的古环境意义进行了初步研究。结果表明:CL剖面中微量元素的含量和分布特征呈有规律的波动变化,反映出区域风化成壤过程中不同元素的地球化学行为存在差异。较高的Mn、Nb、Rb、Cr含量或较低的Ni、As、Sr、Zn、V含量大体指示红土沉积风化作用增强,气候暖湿;反之,则可能指示生物化学风化作用减弱,气候温干或凉干。早更新世晚期以来,研究区古气候经历了温干-暖湿,暖湿,暖湿-干冷,温干-暖湿,暖湿的变化过程。研究揭示出CL剖面微量元素记录的区域气候变化过程既是对全球气候变化的响应,同时也表现出亚热带季风区红土沉积风化的特殊性。     

Mineral magnetism of quaternary red earth in Eastern China and Its paleoenvironmental significance

Mineral magnetic measurements have been made on Quaternary Red Earth profiles from Zhejiang Province, Eastern China. Three distinctive magnetic stratigraphic horizons have been identified on the basis of magnetic susceptibility, anhysteretic remanent magnetization, saturation isothermal remanent magnetization and magnetization parameters measurements. Magnetic measurements revealed that there were great variations in ferrimagnetic mineral concentration, mineralogy assemblages and grain size in Quaternary Red Earth profiles, suggesting that these variations reflect pedogenic processes fluctuation and environmental changes. The preliminary results indicate that mineral magnetic measurement of Quaternary Red Earth is useful for studying the Quaternary environmental changes recorded in paleosols.     

Estimations of primary production and export production in the South China Sea based on sediment trap experiments

The results of time series sediment trap experiments in the South China Sea show that particulate organic carbon (POC) fluxes are influenced by the monsoons. The increase of productivity in the northern South China Sea is mainly due to northeast monsoon while in the central South China Sea the influence of southwest monsoon becomes more prominent. The annual primary production and export production calculated based on POC fluxes are 53.0–63.4 and 10.32–12.93 gC m^-2a^-1, respectively. The enhancement of POC flux during monsoon period suggest that higher palaeoproductivity or organic carbon accumulation rate in glacial age in the South Chma Sea might be the result of strengthening of the monsoons.     

Biodiversity of Early-Middle Ordovician acritarchs and sea level changes in South China

Acritarchs are organic-walled cysts of unicellular pro- tists that cannot be assigned to any known group of or- ganisms. Most acritarchs are probably the resting cysts of marine eukaryotic phytoplankton. Because of their small size, abundance and diversity, as well as widespread distri- bution, acritarchs are very useful in biostratigraphic cor- relation, as well as paleobiogeographic and paleoenviron- mental studies. Furthermore, they represent the fossil re- cord of the base of the marine fo…     

The worm-shaped veins in the red earth of South China--Pedological evidence for root traces of past forest

Field observation of the macromorphology and analyses of micromorphology and geochemistry were conducted to the worm-shaped veins (WSVs) in the red earth of South China.The WSVs exhibit outward features of root traces and contain the traces of stele that can be used as the definite evidence of root traces.Surrounding the worm-shaped veins there are some micro-features pressed by past root growth.Geochemical analyses indicate that the white part in the WSV was depleted in Fe content.These lines of evidence suggest the WSVs in the red earth of South China are the root traces of past forest.     

Paleoclimate change recorded in the red earth and brown-yellow sediment of Late Quaternary for northeastern part of Guangdong Province, south to the Nanling Mountains, China

The paleoenvironment indicated by the geochronology, major oxides SiO2, Al2O3 and TOFE （Fe2O3 ＋ FeO）, and CIA （Chemical Index of Alteration） value of the red earth and brown-yellow silt primarily characterized by the Linjiang stratigraphic section, based on the geological investigation of Late Quaternary along the river banks of northeastern part of China＇s Guangdong Province, south to the Nanling Mountains, allow us to hypothesize that the red earth on the first terrace in northeastern part of Guangdong belongs to reticulated red clay developed in a hot-wet environment of the last interglacial period （132-73 ka BP）, similar to the monsoon environment in the northern margin of modern tropical zone, while the overlying brown-yellow silt layer mainly accumulated in a monsoon environment of warm temperate zone in the last glacial period （73-11 ka BP）, with the aeolian sand LJ3 representing an extreme period of worsening climate. Such a hypothesis corresponds well with predecessors＇ research on the paleoenvironment indicated by abundant fossils in both south and east to the Nanling Mountains. Hence, it follows that the bioclimatic zone did experience a large and rapid vicissitude in northeastern part of China＇s Guangdong Province, and even in the full extent of the region south to the Nanling Mountains from the last interglacial period to the last glacial period, with the red earth being replaced by the brown-yellow silty sediment, and even maybe with the Ailuropoda-Stegodon Fauna being replaced by the Penghu Fauna. This study may provide an important geological demonstration for the environmental response to global change in China＇s low latitudes on a 10 ka scale.     

Trend analysis of sediment grain size and sedimentary process in the central South Yellow Sea

With the method of trend analysis of sediment grain size, the sediment transport trend of the fine-grained sediments area in the central South Yellow Sea was studied. The results demonstrated that there is a sedimentation center around the point of 123.4°E, 35.1°N, and the sediments outside the center are transported to it. The patterns of sediment transportation and deposition in the Yellow Sea should be controlled by cyclonic circulation (including the Yellow Sea Cold Water Mass) and cold water gyre. The study also showed that the method of trend analysis of sediment grain size has prospective utilization in the fine-grained sediment deposited area on large-scale continental shelf.     

南海深海塑料垃圾污染

渔业捕捞及商业航运活动的塑料排放是南海深海塑料污染的主要来源。南海深海微塑料污染始于20世纪80年代,具有明显陆源输入的特征,陆架近岸区域微塑料污染严重。陆坡深海峡谷是塑料/微塑料向深海盆地输运的主要通道,近底浊流在输运中发挥了重要作用。综述了南海海底塑料垃圾深潜研究的最新进展,首次提出了深海塑料垃圾生态系统的概念。     

南海表面海温异常对南海季风影响的数值模拟

采用P-σ混合坐标系区域气候模式模拟了4－7月南海季风的爆发、演变过程，并进行了3组敏感性数值试验，研究南海表面海温异常对南海季风的影响，得到以下结论：（1）南海4月份海温异常对南海季风的爆发日期影响不大，但对季风爆发后的强度有所影响，异常增温造成南海季风增强，异常降温则南海季风减弱。（2）南海季风爆发和强度的变化与南海本身的海温变化情况有密切的关系，尤其是5月份南海海温异常。5月份南海异常增温可以使南海季风提前爆发，季风增强，南海海温异常降低时，南海季风爆发的时间推迟，季风减弱。（3）南海海温持续异常可以影响南海及中国大陆的高低空环流变化，海温持续异常增温可以使南海季风提前爆发，显地加强南海季风，并有利于南海季风向北推进，但当海温在6月份进一步持续增温时，则有利于季风维持在较南地区，阻碍季风向北发展；当海温持续异常降低时，南海季风推迟爆发，且明显减弱。     

南海东部地区语音电话系统设计开发研究

分析了南海东部地区语音电话系统现状,阐述了语音电话系统设计思路及具体设计。