黄河中游黄土区古土壤分布特征及其反映的古气候意义

本文对黄河中游地区古土壤分布特征提出了一些新的认识。该区有过约50决温湿到干冷的古气候波动,形成了约50层古土壤,并将其划分为5个古土壤组合带。     

中国黄土—古土壤序列与第四纪古气候旋回——研究现状、问题与前瞻

中国黄土—古土壤序列记录了过去2.4Ma地质和气候事件的演化历史,总结这方面研究的最新成就和存在的问题,提出了今后应重视的研究方向。     

河北阜城地区晚第四纪孢粉组合及其古植被和古气候演替

通过对阜城地区阜101孔孢粉研究,划分出三个孢粉组合带,从孢粉组合特征清楚地反映出阜城地区自晚第四纪以来古植被、古气候的三个演替阶段。自下而上依次是:1.晚更新世是以松、冷杉、云杉为建群种的针、阔叶混交林-草原,此时气候冷而稍干。2.全新世中期是以松、栎、榆、桦占优势的针、阔叶混交林,为温暖、湿润的气候。3.全新世晚期是以蒿、藜、松和桦为主的疏林-草原,此时气候温凉、略干与现代相近。     

辽南滨海地区黄土磁化率特征及其古气候分析

通过对辽南滨海地区第四纪黄土沉积物的磁化率测量和分析,发现该区马兰黄土的磁化率值不高,反映了该区晚更新世受末次冰期影响,气候条件干冷,黄土粉尘沉积速率快,成壤作用微弱;时间更早的离石黄土磁化率值偏高,反映其成土环境较为温暖潮湿,黄土粉尘堆积速率慢,成壤作用好。磁化率曲线的波动变化反映了古气候发生多次旋回变化;黄土-古土壤序列很好的指示了干冷、暖湿气候的交替,也对应了冬季风、夏季风的交替变化。根据磁化率值对古气温和古降水量的回归计算得到古气温应介于5.85℃～13.0℃（＋1.5℃）,古降水量介于403.22mm～735mm,其标准都低于当今水平。反演辽南滨海地区中、晚更新世时期的黄土沉积环境是比较干冷的,并且经历了多次的小规模的干冷、暖湿交替变化。     

洛川黄土碎屑锆石的粒度特征及其古气候意义

目的 通过对洛川剖面12个层位的锆石粒度分析测量,探讨洛川黄土-古土壤及新近纪红黏土中碎屑锆石的粒度特征及其反应的古气候变化特征.方法 利用Quanta400 FEG场发射环境扫描电子显微镜获得锆石的二次电子图像,并用Scandium软件对锆石的二次电子图像进行粒径测量.结果 第四纪黄土-古土壤及新近纪红黏土中存在大量碎屑锆石,除L24层黄土外,其余黄土层中的锆石粒度均显示出相似的分布特征,主要粒级分布于20～60μm之间,与全岩粒度相比,其中值粒径、平均粒径均有差异,但L9与L15层中锆石中值粒径与全岩差异最小,红黏土中差异最大.结论 成壤作用对粉尘沉积物全岩粒度分析结果影响较大,而对稳定重矿物锆石粒径影响较小.第四纪黄土L9与L15层全岩粒度分析中粗颗粒含量明显增加,应归因于此时粉尘沉积物土壤化过程中成壤作用减弱.新近纪红黏土粗颗粒锆石百分含量的增加,并不预示着此时冬季风的明显加强,而是与周缘裸露的基底岩石提供了近距离的物源有关.L24层黄土在各项粒度指标均显示出其特殊性,可能与青藏高原的阶段性隆升有关.     

黄土高原朝那剖面风尘堆积序列磁化率的古环境意义

黄土高原中部连续的风尘堆积黄土-红粘土序列,蕴含着东亚季风演化与高原隆升等重要的古气候与构造信息.结合已有的古地磁年代,根据磁化率的变化特征对黄土高原中部朝那黄土-红粘土剖面记录的古环境变化进行了划分,共划分I(8.1～5.6 MaBP)东亚季风的初显期、Ⅱ(5.6～4.8 MaBP)东亚夏季风开始增强期、Ⅲ(4.8～...     

广州地区晚第四纪孢粉气候研究

 利用广州地区南北2个不同沉积地貌区的钻孔进行孢粉分析,结合测年和沉积信息,分析了广州所代表的珠江三角洲地区晚更新世以来的沉积环境和气候变化。孢粉分析结果显示：在晚更新世珠江三角洲地区气候经历了偏冷干-偏凉干-暖湿-热湿-偏凉干-冷干的变化过程,末次冰期对本区具有明显影响,使全新世和晚更新世孢粉组合表现出一定的差异;全新世气候明显转暖湿,整体上以暖湿为主,但出现了一些小的气候波动事件,最明显的是在2 250 a BP 前后偏凉干的变化;该区在晚更新世和全新世各经历过一次海侵,两孔反映的气候期和海平面变化较为一致,气候和海平面变化也有很好的对应。两孔在地层、沉积相和孢粉特征上的差异是地理位置、沉积环境和基座地貌等差异造成的。     

东营凹陷早第三纪古气候变化对层序发育的控制

依据东营凹陷下第三系地层中的孢子、花粉资料,用ＲＱ型因子分析方法对其古气候特征进行了恢复。结果表明,干旱气候背景下东营凹陷下第三系的气候周期性变化与湖盆中的层序发育有良好的对应关系。气候的周期性变化导致湖盆中湖平面的变化,从而控制并发育了具有低水位、湖泊扩张、湖泊收缩和高水位体系域的气候层序。这种气候层序与海相层序具有相似的层序发育控制因素、体系域组成和水平面变化规律,但它的分布范围和层序厚度都比海相层序小。     

柴达木盆地与珠江三角洲地区晚第四纪气候变化比较研究

第四纪晚期柴达木盆地与珠江三角洲的气候都呈现出冷暖旋回的波动特征,引起相应的环境变迁.但两地各期的波动起讫时间年代有较大差异,柴达木盆地的降温时间明显早于珠江三角洲地区,降温幅度明显.两地都有全新世气候适宜期,但纬向和经向的差异都很大.两地的气候波动变化、进退迁徒、突发事件的对比在一定程度上反映或代表中国大陆上气候演变的普遍特征.     

杭州湾南岸慈溪地区晚第四纪沉积与古环境演化

杭州湾作为我国大陆沿海地区第四系厚度较大的沉积区之一,历来是我国地学、生物学和气候学研究的重点区域;但其南岸研究比较薄弱。在对杭州湾南岸第四系BZK1钻孔岩芯沉积物特征、地质年代、孢粉、有孔虫和介形类分析基础上,探讨了杭州湾南岸第四纪地层对比、古环境演化和海平面变化特征。钻孔揭示全新世沉积始于孔深22.00 m(约10.77 ka B P.),其下至孔深44.60 m为晚更新世地层,全新世沉积速率大于晚更新世。研究表明:古环境变化可划分为4个阶段:29.6~10.8 ka B P.晚更新世时期,以针叶、阔叶混交林为主,为气候温暖较湿的滨海河口湾半咸水环境;10.8~9.5 ka B P.早全新世早期,以针叶与常绿阔叶林为主,推测属亚热带温暖湿润气候下的潮上带湖沼环境;9.5~5.9 ka B P.全新世早中期,以常绿阔叶与针叶林为主,气候温和较湿,受海水波及;5.9~0.5 ka B.P.全新世中后期,以常绿阔叶与针叶林为主,属滨海-内陆架环境,该阶段后期海水已退出本区,气候由温暖湿润渐渐转凉。结果显示杭州湾南岸气候-环境-海平面-沉积速率之间具有较好的对应。上述研究可丰富杭州湾南岸第四纪地层学、环境地质学研究内容,为邻区晚更新世生物地层对比以及古植被和古环境分析提供证据。     

中国北方新近纪红黏土记录的古气候意义——与动物群化石序列对比

目的研究中国北方新近纪红黏土序列的古气候演化特征。方法对中国北方4个新近纪红黏土剖面沉积物的粒度、磁化率和化石动物群时间序列进行区域对比。结果黄土高原新近纪红黏土沉积以来发生了5次大的气候事件,气候事件的分界线在粒度、磁化率年龄曲线上特征明显,反映的气候特点与化石动物群演替性质完全一致。结论中国北方新近纪红黏土序列古气候演化过程的气候事件均与青藏高原隆升和东亚季风的发展相联系。时间上,南北气候演化事件基本同步;空间上,北部较南部地区变化剧烈。5次气候事件从下到上表现为半湿润、半干旱、湿润、干旱与湿润交替、干旱的气候演化特征;相应动物群生态类型表现为草原-疏林草原、草原为主的疏林草原、森林、草原荒漠与森林交替到草原的演化特点。     

The ecological sequence of Hipparion fauna in the mid-dle reaches of the Yellow River during Neogene

The faunal ecological type and sequence in the Tertiary red clay indicate that Hipparion fauna during the period 7.4-6.1 Ma in the middle reaches of the Yellow River is composed mainly of dorcadoides and mixed types. This represents semiarid veld environment with small fluctuation. The fossil assemblages characterized by the abundance of gaudryi types and even the occurrence of some Hominoid and Chalicotherium indicate an obviously warm and humid period since 5.3 Ma. The fossil assemblages during 3.4 Ma show the typical steppe fauna representing dry climate. It is indicated by the changes of ecological sequence that the climatic conditions in Pliocene are drier than that in late Miocene. The clay-skin content of red clay, which has a synchronous change with faunal features, is a rather good replacing palaeoclimatic index.     

中国北方晚新生代红粘土研究之若干问题

对于中国北方地区晚第三纪以来沉积的红粘土的成因,近年来不少学者通过对其粒度、地球化学及古生物等替代性指标的研究,认为该套沉积物为风尘沉积.通过大量野外考察、理论与室内分析测定,认为粒度、地球化学等指标存有多解性,而古生物证据与所谓风成的干旱化环境不相一致,上述指标并不足以成为红粘土风成的确凿证据因此,进一步深入研究相关替代性指标的研究是今后努力的方向,对红粘土成因的确认不能仅局限于青藏高原的可能影响,全球环境的变化才有可能是解决问题的关键途径.参17.     

黄土高原晚第三纪红土的形态学和地球化学特征及其环境指示意义

对甘肃西峰地区晚第三纪红土和第四纪风成典型黄土的化学元素、矿物组成和矿物颗粒形态特征研究揭示出，该区红土下部（６．２ＭａＢ．Ｐ．前）是红化的土壤物质与其它物质一起经流水搬运再堆积的产物；中部（６．２Ｍａ～３．４ＭａＢ．Ｐ．）未发现再搬运的痕迹，是风尘堆积经风化和间歇性地下水位波动作用所形成的；上部（３．４～２．６ＭａＢ．Ｐ．）是典型的风尘堆积－土壤序列。由于干旱区的存在是黄土高原风尘堆积的前提条件     

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.     

The ecological sequence of Hipparion fauna in the middle reaches of the Yellow River during Neogene

The faunal ecological type and sequence in the Tertiary red clay indicate that Hipparion fauna during the period 7.4–6.1 Ma in the middle reaches of the Yellow River is composed mainly of dorcadoides and mixed types. This represents semiarid veld environment with small fluctuation. The fossil assemblages characterized by the abundance of gaudryi types and even the occurrence of some Hominoid and Chalicotherium indicate an obviously warm and humi period since 5.3 Ma. The fossil assemblages during 3.4 Ma show the typical steppe fauna representing dry climate. It is indicated by the changes of ecological sequence that the climatic conditions in Pliocene are drier than that in late Miocene. The clay-skin content of red clay, which has a synchronous change with faunal features, is a rather good replacing palaeoclimatic index.     

苏宏图白垩系粘土岩元素地球化学和粘土矿物特征及其古气候意义

为了探究苏宏图地区白垩系苏红图组的古气候环境,应用X射线荧光光谱(XRF) 和电感耦合等离子体质谱(ICP-MS) 方法研究了粘土岩样品的元素地球化学特征,结果表明：P、Mn、Sr/Cu、Mg/Ca、SiO2/Al2O3等元素特征指示白垩系苏红图组总体呈现极度干燥的沉积环境,不同亚相之间沉积环境稍有干湿变化,且扇三角洲相对湿暖;通过XRD和SEM方法研究了全岩矿物组成和粘土矿物类型和组合特征,结果表明：伊利石为主要的粘土矿物,其次为绿泥石、高岭石,粘土矿物的组合类型为伊利石、绿泥石的组合,且绿泥石和高岭石呈现此消彼长的现象,反映了干燥寒冷的沉积环境,并伴随着干湿的气候变化。     

Magnetostratigraphy of Late Tertiary sediments from the Chinese Loess Plateau and its paleoclimatic significance

The Late Tertiary red clay/bed sediments underlying the Quaternary loess-paleosol in the Chinese Loess Plateau possesses high-resolution paleoclimatic changes related to the uplift of the Tibetan Plateau. Magnetostratigra-phy and susceptibility measurements are discussed in this paper. The paleomagnetic results show that the red clay/bed began to accumulate at about 8.1 Ma, which represents the oldest Late Tertiary deposit continuously in the central Loess Plateau. The magnetic susceptibility curves show stepwise increases since the initiation of red clay, superimposed on several peaks. Moreover, the magnetic susceptibility increased abruptly since 3.8 Ma, which probably indicates the inception of the modern East Asia monsoon system. Between 3.8 and 2.6 Ma, the stepwise increases of susceptibility may imply progressively intensified East Asia summer monsoon activity related with the stepwise uplift process of the Tibetan Plateau.     

长江三角洲晚第四纪地层层序特征

通过289口钻孔资料的分析,以下切河谷底部的侵蚀面及河间地古土壤层顶面为层序界面,据此将长江三角洲晚第四纪地层划分为三个层序,古河谷和古河间地的层序界面埋深相差较大,但所划分的三个层序在横向上可以进行对比,长江三角洲晚第四纪地层存在古河谷相序和古河间地等两类相序以及四种层序组合方式,其中三期古河谷充填层序具有套叠式结构,证明古河谷的发育具有继承性,且规模逐渐缩小,长江晚第四纪古河谷经历了“下切—充填—海泛—三角洲进积—再下切”的周期性发育过程     

Preliminary research on Megalake Jilantai-Hetao in the arid areas of China during the Late Quaternary

We identified geomorphological, sedimentary and biological evidence of high lake levels around the current Jilantai Salt Lake through field investigations and through analyses of regional remote sensing images. There are four groups of shorelines at elevations of around 1060, 1050, 1044 and 1035 m a.s.l., being 37, 27, 21 and 12 m above the current salt lake surface, respectively. Littoral deposits of sand and gravels are found at elevations between 1070 and 1080 m a.s.l., 47 to 57 m higher than the current salt lake surface, although palaeoshoreline landforms are only preserved at several sites. At Herimuxini, on the northern margin of the Ulan Buh Desert, typical lacustrine sediments and sand-gravel littoral deposits also occur at elevations of 1080 m a.s.I, and below. A 11-km-long typical spit extends eastward from this shoreline gradually reducing in elevation from 1050 to 1035 m a.s.I. In some sand-gravel quarries along the southern bank of the Yellow River on its Great Bend, such as those located near the Hydrological Gauge Station and Shilazhao Town, shoreline features were identified. Littoral deposits overlying the alluvial-diluvial layers occur in a sand quarry near Balagong in Hangjin County. There are also beachrock and littoral deposits preserved on the cut-and-built terraces at several sites along the southern piedmont of Langshan-Yinshan Mountains. In addition, a profile revealing subaqueous delta sediments was identified near Wuhai, where the Yellow River enters the basin. Typical lake sediments also exist at the Togtoh Platform on the eastern end of the Hetao Plain. Aquatic Mollusk shells are common in the littoral deposits, including several species of Corbicula, Radix lagotis, R. xauricularia and Gyraulus convexiusculus. Ostracode shells can also be identified in finer sediments. Typical ver- tical prograding sequences are evident in outcrops where lacustrine sediments were well preserved. Wave-rolled cobbles and beachrock are very commonly preserved on the top of profiles in the embankments at