古气候变化对大同盆地第四纪沉积物中砷富集过程的影响

为揭示古气候变化对大同盆地第四纪含水层中砷(As)富集的影响,对盆地中部的第四系沉积物钻孔样品 进行了地球化学分析.结果表明,大同盆地第四系沉积物中的铁矿物、黏土矿物以及有机质均为 As的重要赋存 载体.根据沉积物地球化学特征,可将沉积物由深到浅依次划分为４层,分别对应中更新世暖湿期、中更新世干 冷期、末次间冰期暖湿期及末次冰期的干冷期.暖湿期沉积物中的 As及铁矿物、黏土矿物、有机质含量均明显高 于干冷期,说明暖湿气候更有利于铁矿物、黏土矿物和有机质在沉积物中埋藏堆积,促进了沉积物中 As的富集.      

中国东北第四纪冰川研究新进展:遗迹厘定、新发现与冰期模式

东北是否发育第四纪冰川及其范围、性质与冰期问题,始终没有定论。在对长白山及大兴安岭冰川遗迹厘定基础上,进行了专项调查,并采用地理信息系统(GIS)、遥感(RS)及全球定位系统(GPS)的3S技术,采取钻探测图、孢粉、泥砾粒度与渗透性分析及14C定年等方法,在长白山及大兴安岭发现了冰蚀谷及泥砾堆积等新的冰川遗迹,进一步肯定了两座山地第四纪冰川的存在及其多期性。在小兴安岭首次发现冰蚀岩墙等冰川遗迹,填补了研究空白,证明小兴安岭也曾发育第四纪冰川。综合多种信息,确定长白山与大兴安岭分别有4次冰期和3次间冰期,小兴安岭至少有1次冰期。最后构建了可以与国际对比的冰期序列,重建了区域第四纪冰川环境演化模式:早更新世早期冷干,中晚期偏暖湿;中更新世早期冷湿,中晚期暖湿;晚更新世早期冷稍湿,中期暖湿,晚期冷干。     

大别山北麓黄土-古土壤地球化学元素特征及富集因子法物源研究

为了解大别山北麓自中更新世以来黄土-古土壤的沉积环境及物质来源,对其地球化学元素进行了测定。结果表明,
研究区沉积物的地球化学元素组成具有富硅、铝、铁,贫钙,低钠、镁、钾、钡、锶的特点。通过对气候特征元素变化的进一步分析,
表明大别山北麓自中更新世以来是以温湿为主且从老至新气候由温湿向干冷趋势发展,与洛川黄土相比,大别山黄土经历了更强
烈的化学风化作用。选择化学性质稳定的Ti、Sc、Th、Nb作为参比元素,运用富集因子法进行地球化学元素研究进而判别物质来
源,结果表明,大别山北麓黄土-古土壤与洛川黄土同源,均来自西北的风尘堆积。      

南阳盆地更新世以来的孢粉分析及其古气候记录

通过对南阳盆地的2个控制性钻孔样品进行精确的光释光定年、ESR定年和孢粉分析,结合现代表土植被概貌,重建了该区更新世以来的植被和环境演化历史。结果表明,早更新世,该区以草原和森林植被的草本植物为主,略大于木本植物,后期随着森林植被的发育,沉积环境相对稳定;中更新世主要表现为木本植物快速减少,蕨类也减少,其次是水生和陆生草本植物的相应增加;晚更新世,主要表现为次生的松属植被明显增加,水生植物明显减少;全新世,钻孔最上部藻类植物的大量增加,反映了水体面积较大,表明该时期该区水量丰沛。区域对比显示,该区从更新世到全新世气候温暖湿润,变化不大,未出现过冰期气候,各时段的气温差异不大,但干湿变化比较明显。气候环境演化特征与典型的东亚季风影响区有着明显差异,这与南阳盆地局部的环境有密切关系。      

辽宁第四纪哺乳动物群与古气候的演变

根据辽宁十二个哺乳动物群和年代地层学资料,中更新世中、晚期至晚更新世晚期所反映的古气候大致经历了温暖潮湿、寒冷干燥、温和湿润、寒冷干燥四个阶段,从而初步建立了辽宁地区中更新世中、晚期至晚更新世晚期的古气候演变序列。从动物群的生态类型看,中更新世至晚更新世的动物群具有华北—东北过渡类型的性质,而晚更新世晚期的动物群则具更多的寒温带生态环境的色彩。     

汉江郧阳段河流阶地发育特征及新构造运动意义

在野外调查的基础上,分析汉江郧阳段河流阶地的发育特征。结合地质、地貌及第四纪测年学资料,推断汉江T1~T5阶地形成的时代分别为全新世-晚更新世末期（约25 ka BP）、晚更新世（约67 ka BP）、晚更新世早期-中更新世末期（约128 ka BP）、中更新世早期-早更新世晚期（约1 344 ka BP）、不晚于早更新世。阶地的横向对比显示,两陨断裂的活动导致汉江五峰段、青曲段、郧阳盆地段T3、T2阶地在垂向上构造隆升的差异性,结合T3、T2阶地的形成时代,推测断裂活动的时代为中更新世末期-晚更新世早期。近似地推算汉江郧阳段更新世早期以来的平均隆升速率约为0.052 mm/a,显示抬升速率及幅度较秦岭弱,可能由于汉江郧阳段处于秦岭东南缘余脉,并非秦岭隆升的中心地域。     

大连地区更新世的哺乳动物

大连地区碳酸盐岩分布广泛 ,裂隙溶洞发育 ,洞穴堆积物中蕴含了丰富的更新世哺乳动物化石和古文化遗物 ,在境内陆地和附近海域陆续发现了 30余处化石点。在众多的化石点中尤以古龙山遗址和大连动物群最引人注目 ,前者在同一地点内采集到 377种上万件的脊椎动物骨骼化石 ,并伴有石器、骨器、灰烬等远古人类活动的遗物 ;后者包括了 2 8种早更新世的小型哺乳动物 ,这是大连乃至东北地区的首次报导。这些事实说明了东北地区不只是仅有晚更新世的动物群 ,至少还有早更新世的大连动物群 ,即使在晚更新世 ,也不只是单一的披毛犀 -猛犸象动物群 ,还存在着具有从华北向东北过渡性质的古龙山动物群。今后工作中应注意寻找古人类及中更新世的哺乳动物化石 ,加强对全新世动物遗骨的研究。     

“一带一路”沿线国家农田生态系统脆弱性及其对气候变化的响应

全球气候变化背景下,“一带一路”沿线国家农田生态系统脆弱性直接影响着所在国家或地区的粮食安全问题。本文基于农田生态系统总初级生产力（GPP）,使用定量的脆弱性评价方法,系统分析了“一带一路”沿线国家农田生态系统脆弱性的空间分布特征及其对气候变化的响应。结果表明：① “一带一路”沿线国家农田生态系统脆弱性普遍处于较高的程度,77.1%的农田生态系统表现为中度和重度脆弱,且农田生态系统脆弱性呈现出明显的空间分异格局,中亚、西亚和蒙古脆弱性较高,中国、东南亚和南亚的脆弱性处于中等水平,俄罗斯、独联体和中东欧脆弱性较低;② 1980年以来“一带一路”沿线农田生态系统暖干化趋势明显,暖干化区域面积占64.06%,暖干化是“一带一路”沿线国家农田生态系统气候变化的主要特征;③ 农田生态系统脆弱性由低到高的气候变化区依次为暖湿区、冷湿区、暖干区、冷干区。暖湿区农田生态系统脆弱性最低,而冷干区农田生态系统脆弱性最高。气温和降水的变化及其耦合关系控制着农田生态系统脆弱性程度,其中降水变化趋势是影响农田生态系统脆弱性的重要因子。本研究为“一带一路”沿线国家应对和解决粮食安全问题,促进农业可持续发展,为加强各国之间的农业国际合作提供科学依据和有益参考。     

陕西临潼牡丹沟断裂带的构造岩

本文从应力矿物的变形现象;构造岩岩石类型;破碎矿物颗粒的粒径变异;构造岩化学元素的迁移变化和构造岩胶结物及胶结类型的变化等几方面讨论了在宏观上表现为正断层的陕西临潼牡丹沟北北东向断裂带的构造岩石学特征,从而确定了该断裂为一以扭为主的压扭性力学性质的破裂结构面,是快速应力作用的结果,其影响宽度可达三十米,断裂化学元素迁移能力顺序为钾、钠、铝、钙、镁、钛、铁、硅。     

第四纪洞庭盆地安乡凹陷及西缘构造-沉积特征与环境演化

通过地表观察和钻孔资料,对洞庭盆地安乡凹陷及其西缘第四纪构造沉积特征和环境演化进行了研究,为江汉—洞庭盆地第四纪地质研究补充了新的资料。凹陷总体呈南北向,周边为正断裂。凹陷内第四系厚一般为100~220 m,最厚达300 m,自下而上依次为早更新世华田组、汨罗组,中更新世洞庭湖组,晚更新世坡头组和全新世湖冲积。第四系以砾石层、砂层为主,次为(含)粉砂质黏土、黏土,岩性、岩相横向变化大。安乡凹陷西缘(即太阳山隆起东缘),呈自西向东缓倾的丘岗地貌。区内主要发育中更新世白沙井组,其中南部下部以砂、砾石层为主,上部为黏土;北部以粉砂质黏土沉积为主,下部可发育砂层。根据地貌、沉积及控凹断裂特征,重塑安乡凹陷及其西缘第四纪构造活动与环境演化过程:早更新世—中更新世早期,凹陷西边的北北东向周家店断裂伸展活动,安乡凹陷不均匀沉降,总体具河流和过流性湖泊环境并接受沅水沉积;同期凹陷西缘构造抬升,处于剥蚀的山地环境。中更新世中期断陷活动向西扩展,凹陷区为过流性湖泊环境;凹陷西缘地区转为河流(南部)和湖泊(北部)环境并接受沉积。中更新世晚期安乡凹陷及其西缘整体抬升并遭受剥蚀,凹陷西缘同时具有自西向东的掀斜。晚更新世安乡凹陷拗陷沉降,具河流和湖泊环境;同期凹陷西缘遭受剥蚀。晚更新世末受区域海平面下降影响,安乡凹陷遭受剥蚀。全新世安乡凹陷拗陷沉降,具泛滥平原之河流、湖泊环境。     

对渭河盆地新生界及其年代的讨论

秦岭造山带北缘的渭河盆地，新生界十分发育．前人建立了盆地地层系统．随着地质成果的不断积累，原有的地层系统需要重新整理。在前人工作基础上，根据新的全球变化研究资料和数据，对渭河盆地新生界部分地层的年代做了重新认识。认为红河组形成于古近纪中始新世-晚始新世；白鹿塬组形成于古近纪晚始新世-早渐新世；冷水沟组形成于新近纪中新世早期；寇家村组形成于新近纪中新世中期；灞河组形成于新近纪中新世晚期。蓝田组和游河组不存在层位上下关系，它们可能是地史时期形成的同期异相沉积；三门组的上界年代在不同的地区各不相同，表明古三门湖的消亡时代不同的地区存有差异。蓝田组和游河组形成时期，研究区地形地貌发生分异，表现为地形凸起和凹陷并存，凸起堆积风成沉积，凹陷接受湖泊沉积，这一地貌格局很可能自7．3Ma B．P．以来，一直持续到0．15Ma B．P．，黄土高原的风尘堆积与古三门湖并存的地貌格局是新近纪晚中新世最晚期至0．15Ma B．P．以来研究区重要的地质事件之一，它是当时研究区区域构造运动作用的结果。     

The anisotropy of loess magnetic susceptibility in the northeastern fringe of Qinghai-Xizang Plateau as an indicator of palaeowind direction

ＴＨＥＡＮＩＳＯＴＲＯＰＹＯＦＬＯＥＳＳＭＡＧＮＥＴＩＣＳＵＳＣＥＰＴＩＢＩＬＩＴＹＩＮＴＨＥＮＯＲＴＨＥＡＳＴＥＲＮＦＲＩＮＧＥＯＦＱＩＮＧＨＡＩＸＩＺＡＮＧＰＬＡＴＥＡＵＡＳＡＮＩＮＤＩＣＡＴＯＲＯＦＰＡＬＡＥＯＷＩＮＤＤＩＲＥＣＴＩＯＮＷａｎ...     

The anisotropy of loess magnetic susceptibility in the northeastern fringe of Qinghai-Xizang Plateau as an indicator of palaeowind direction

Estimates of the palaeo-subaerial wind direction were studied systematically for the first time by using the anisotropy of loess magnetic susceptibility (AMS) measurements in the northwestern China. One hundred and forty undisturbed oriented aeolian loess samples were collected from Lanzhou, Linxia and Wudu areas for AMS measurements, which indicated the subaerial wind directions were not the same while the loess deposited. From the Early Pleistocene to Middle Pleistocene till Late Pleistocene, the wind direction experienced an anticlockwise rotation in the studied area. We suggested this change was related to the uplift of the Qinghai-Xizang Plateau and the adjustment of current and landform effects.     

Studies on quaternary sporo-pollen assemblage and paleoclimate based on Bohai Sea core Bc−1

Analysis of 13 spore-pollen assemblage zones reflecting environmental changes since the later middle Pleistocene showed the seccession of paleovegetation and the paleogeographic changes in the Bohai Basin and circumjacent area. Paleoclimatic variations here can obviously be divided into 5 cold and 5 warm periods: 2 cold and 1 warm periods in 200,000–100,000 a B.P.(late middle Pleistocene) 3 cold and 3 warm periods in 100,000–12,000 a B.P.(late Pleistocene), and 1 warm period since 12,000 a B.P. Late Pleistocene climate tended to become colder and colder. The coldest period was in the later stage of late Pleistocene, when the study area was a periglacial zone. The mean annual temperature then was about 10°C lower than it is now. In the middle stage of late Pleistocene, climate became warm; the mean annual temperature then was about 3–4°C higher than it is now. By applying principles of climatic stratigraphy, the authors deduced through sporo-pollen analysis, that the boundary between middle and late Pleistocene should be at 178–181 m, and that between Pleistocene and Holocene should be at 12.8 m. The results of climatic stratigraphy are consistent with those of magnetic stratigraphy. This paper was published in Chinese inOceanologica et Limnologia Sinica.18 (3): 253–266, 1987.     

Last glaciation and maximum glaciation in the Qinghai-Xizang (Tibet) Plateau: A controversy to M. Kuhle’s ice sheet hypothesis

Since the late 1950’s, many Chinese scientists have explored the remains of the Quaternary glaciation in the Qinghai-Xizang (Tibet) Plateau and its surrounding mountains. In the main, 3–4 glaciations have been recognized. The largest one occurred in the Late Middle Pleistocene with piedmont glaciers, ice caps and trellis valley glaciers in many high peak regions. But here is no evidence of a unified ice sheet covering the whole plateau as described by M. Kuhle. Due to the further uplifting of the Himalayas and Qinghai-Xizang Plateau the climate became progressively driver, diminishing the extension of glaciers during the Late Pleistocene. The elevation of the snow line during the Last Glaciation was about 4,000 m on the south, east and northeast edges of the plateau and ascended to 5500 m on the hinder northwest of the plateau. The thermal effect of the big plateau massif, the sharp increase of aridity from the southeast rim to the northwest inland area and the abrupt decrease of precipitation during the Ice Age largely account for the distribution of the Quaternary glaciers in the Qinghai-Xizang Plateau. The neglect of Chinese literature may be one of the causes accounting for M. Kuhle’s misinterpretation on the environment of the Quaternary glaciations in the Qinghai-Xizang Plateau.     

LAST GLACIATION AND MAXIMUM GLACIATION IN THE QINGHAI-XIZANG (TIBET) PLATEAU: A CONTROVERSY TO M. KUHLE,S ICE SHEET HYPOTHESIS

Since the late 1950's, many Chinese scientists have explored the remains of the Quaternary glaciation in the Qinghai-Xizang (Tibet) Plateau and its surrounding mountains. In the main, 3-4 glaciations have been recognized. The largest one occurred in the Late Middle Pleistocene with piedmont glaciers, ice caps and trellis valley glaciers in many high peak regions. But here is no evidence of a unified ice sheet covering the whole plateau as described by M. Kuhle. Due to the further uplifting of the Himalayas and Qinghai-Xizang Plateau the climate became progressively drier, diminishing the extension of glaciers during the Late Pleistocene. The elevation of the snow line during the Last Glaciation was about 4,000 m on the south, east and northeast edges of the plateau and ascended to 5500 m on the hinder northwest of the plateau. The thermal effect of the big plateau massif, the sharp increase of aridity from the southeast rim to the northwest inland area and the abrupt decrease of precipitation during the     

Influence of climate on soil organic carbon in Chinese paddy soils

Soil organic carbon (SOC) is a major component of the global carbon cycle and has a potentially large impact on the greenhouse effect. Paddy soils are important agricultural soils worldwide, especially in Asia. Thus, a better understanding of the relationship between SOC of paddy soils and climate variables is crucial to a robust understanding of the potential effect of climate change on the global carbon cycle. A soil profile data set (n = 1490) from the Second National Soil Survey of China conducted from 1979 to 1994 was used to explore the relationships of SOC density with mean annual temperature (MAT) and mean annual precipitation (MAP) in six soil regions and eight paddy soil subgroups. Results showed that SOC density of paddy soils was negatively correlated with MAT and positively correlated with MAP (P < 0.01). The relationships of SOC density with MAT and MAP were weak and varied among the six soil regions and eight paddy soil subgroups. A preliminary assessment of the response of SOC in Chinese paddy soils to climate indicated that climate could lead to a 13% SOC loss from paddy soils. Compared to other soil regions, paddy soils in Northern China will potentially more sensitive to climate change over the next several decades. Paddy soils in Middle and Lower Yangtze River Basin could be a potential carbon sink. Reducing the climate impact on paddy soil SOC will mitigate the positive feedback loop between SOC release and global climate change.     

黄土高原晚更新世的植被与气候环境

在被认为孢粉贫乏的黄土中分析出了大量孢粉,首次作出了黄土地层的孢粉浓度图式。根据１０余个剖面上孢粉组合的变化,阐明了晚更新世的植被与气候在时间上演替与空间上分布的规律,证明了各地植被在时间上的演变韵律十分相似,说明它们同受全球气候变化的控制,但同一时期在空间上各地植被不尽相同,此乃局地自然环境差异所致。根据植被变化重建了古气温曲线。     

黄河东段形成时代管见

通过汾渭盆地与河南平原地区更新统介形类化石组合的对比，作者认为：黄河东段（三门峡以东）形成的时代为中更新世初期或早更新世末期，里今约七八十万年至一百万年左右。