中原邙山黄土地层划分的讨论

地层时代和地层划分研究一直是基础性、先导性工作,随着科学研究的深入和材料的丰富,地层划分不断被重新认识。黄土地层时代和划分主要依靠OSL、^(14)C、古地磁和磁化率的对比。中原邙山因发育巨厚的马兰黄土而闻名中外,但地层划分却出现了不同的认识。早期对赵下峪剖面的研究认为L_1层厚98 m,并发育L_1SS_1弱古土壤层;剖面底部出露最老地层为S_(10)层。后来的观点把早期的L_1层划分为L_1、S_1、L_2层,剖面底部出露最老地层为S_(11)层。通过对B/M界线进行详细的古地磁研究,剖面上部补充年代测试样品,结合已有测年结果,分析认为早期对L_1的划分和对剖面最老地层的确认是正确的,但B/M界线位置划分有误;而后期的研究对B/M界线位置的划分是正确的,但把底部最老地层划分为S_(11)是不当的,同时把马兰黄土中弱古土壤层L_1SS_1划分为S_1也是不合适的。地层对比表明,邙山黄土发育了S_0—S_(10)黄土—古土壤序列,B/M界线位于L_8下部。

湘西秸秆资源化利用现状及其在植烟土壤改良中的应用

阐明了农作物秸秆的利用价值和利用方式,分析了湖南省湘西州秸秆资源及其利用现状,探讨了农作物秸秆在烟草生产上利用的利弊,提出了农作物秸秆在湘西州植烟土壤改良上的应用对策。

Late Cenozoic Sedimentary Evolution of Pagri-Duoqing Co graben, Southern End of Yadong-Gulu Rift, Southern Tibet

The north trending rifts in southern Tibet represent the E-W extension of the plateau and confirming the initial rifting age is key to the study of mechanics of these rifts. Pagri-Duoqing Co graben is located at southern end of Yadong-Gulu rift, where the late Cenozoic sediments is predominately composed of fluvio-lacustrine and moraine. Based on the sedimentary composition and structures, the fluviolacustrine could be divided into three facies, namely, lacustrine, lacustrine fan delta and alluvial fan. The presence of paleo-currents and conglomerate components and the provenance of the strata around the graben indicate that it was Tethys Himalaya and High Himalaya. Electron spin resonance(ESR) dating and paleo-magnetic dating suggest that the age of the strata ranges from ca. 1.2 Ma to ca. 8 Ma. Optically stimulated luminescence(OSL) dating showed that moraine in the graben mainly developed from around181-109 ka(late Middle Pleistocene). Combining previous data about the Late Cenozoic strata in other basins, it is suggested that 8-15 Ma may be the initial rifting time. Together with sediment distribution and drainage system, the sedimentary evolution of Pagri could be divided into four stages. The graben rifted at around 15-8 Ma due to the eastern graben-boundary fault resulting in the appearance of a paleolake.Following by a geologically quiet period about 8-2.5 Ma, the paleolake expanded from east to west at around 8-6 Ma reaching its maximum at ca. 6 Ma. Then, the graben was broken at about 2.5 Ma. At last,the development of the glacier separated the graben into two parts that were Pagri and Duoqing Co since the later stages of the Middle Pleistocene. The evolution process suggested that the former three stages were related to the tectonic movement, which determined the basement of the graben, while the last stage may have been influenced by glacial activity caused by climate change.

Geochemical Characteristics of Eolian Deposits in the Chengdu Plain of Sichuan Province and the Implications for Provenance

In this study Chengdu Red Earth （CRE） from the Chengdu Plain （CP）,Sichuan province,was analyzed for its elemental （major and trace elements） and isotopic （Sm-Nd） geochemistry and compared with Pleistocene loess and paleosol samples from the Chinese Loess Plateau （CLP） in Northern China.The geochemical composition of CRE is similar to north China loess,and also resembles the average UCC.This indicates that CRE,as loess deposits in Northern China,was derived from well-mixed sedimentary protoliths that have undergone numerous upper crustal recycling processes.However,obvious differences in the geochemical characteristics of CRE and the north China loess are also revealed in our results.For chemically stable elements,CRE has higher Ti,Zr,Hf and lower ΣREE,Ba contents in comparison with loess samples from the CLP.Further analysis shows that CRE has higher TiO2/Al2O3,SiO2/Al2O3,Ba/Rb and lower Ce/Yb,Eu/Yb,LaN/YbN and ΣLREE/ ΣHREE ratios.In Sm-Nd isotopic geochemistry,Sm and Nd content and the εNd（0） value in CRE are significantly higher than those in north China loess.The higher TiO2 content in CRE coincided with a high background concentration of Ti in the Sichuan Basin and the surrounding regions.The lower ΣREE and higher Sm,Nd,εNd（0） values are related to the wide distribution of basalt in the southwest Sichuan Basin.The elemental and isotopic geochemistry of CRE indicates that eolian materials in the CP predominantly come from the Sichuan Basin and the surrounding regions,which differs from loess deposits in the CLP.

基于PWM的气动软体空间机械臂压力控制系统

针对气动软体空间机械臂的压力控制需求,提出了基于脉宽调制(PWM)的软体臂压力控制技术。设计了气动软体空间机械臂的气动系统结构,并建立了各部分的数学模型。根据开关阀和PWM控制的特性,提出了基于零位补偿和双阀同步PWM的软体臂压力控制系统结构,并阐述了各部分设计方法。利用Python建立了整个系统的仿真模型,并将仿真结果与实验结果进行了对比,对比结果表明,模型具有一定的准确性。对该压力控制系统进行了正弦跟踪实验,实验结果表明,该系统可以进行低频跟随,能够满足气动软体空间机械臂的压力控制需求。

Initial Rifting Age of the Nearly N–S Rifts in Southern Tibetan Plateau:New Evidence from the Age limit of the Early Sediments

Objective The nearly parallel N-S-trending rifts in southern Tibet represent the E-W extension of the Tibet Plateau. Most data which constrained the age of the extensional deformation come from isotopic dating of the dikes probably related to the activity of the nearly N-S faulting and micas from hydrothermal activity and the low- temperature thermochronology of plateau uplift. Previous research shows that there are at least three different ideas about the age of the rifts： （1） older than 16-12 Ma, （2） 14- 10 Ma, and （3） 8-4 Ma （Fig. la）. For the old sedimentary strata represented the beginning of the rifting, the dating of the sediments helps to better define the initial rifting age.

内蒙古托克托郝家窑剖面粒度特征与环境探讨

郝家窑剖面厚47m,其中湖相沉积厚43.5m。沉积物粒度频率曲线呈现双峰、三峰和四峰等多种类型;粒度呈现多组成分布,从纵向分层情况看,频率曲线变化呈现一定规律。粒度总体以粉砂及砂为主,下部地层以分选相对较差的粗颗粒砂为主,上部以分选较好的细颗粒黏土与粉砂构成。该区环境经历了三次不同环境阶段演化,阶段Ⅰ(深度30~47m)为水动力较强的动荡环境,气候湿润,降水量大且波动频繁;阶段Ⅱ(深度3.5~30m)为水动力较弱的稳定环境,气候干旱,其中在深度20.35~22.3m段反映出一次突然且持续的湿润气候环境;阶段Ⅲ(深度3~3.5m)湖相沉积结束,黄河切穿古湖,湖水迅速外泄,风成沉积指示了干旱的环境特征。

Late Cenozoic Geology and Paleo-environment Change in the Eastern Edge of Qinghai-Xizang Plateau

There are late Cenozoic lacustrine deposits and loess and red clay and moraines in eastern edge of the Qinghai-Xizang Plateau. Various genetic sediments recorded rich information on late Cenozoic paleo-environment changes. Xigeda lacustrine formed during 4.2 Ma B.P.-2.6 Ma B.P. There were 9 periodic warm-cold alternations. Eolian deposition in western Sichuan began at 1.15 Ma B.P. The loess-soil sequences recorded successively 14 paleo-monsoon climate cycles. Laterite in Chengdu plain recorded 5 stages of paleoclimatic stages since 1.13 Ma B.P. There was an old glacial period of 4.3 Ma B.P. in eastern Qinghai-Xizang Plateau. During Quaternary, there are 5 extreme paleoclimatic events corresponding with 5 glaciations.

基于CoppeliaSim的空间环境腔体式气动软体臂仿真

研究了一种用于腔体式气动软体臂在空间环境抓抱动作的运动学和动力学仿真技术。利用CoppeliaSim和Python通过API接口的方式联合仿真。在CoppeliaSim中将软体臂等效成多个铰接的刚体支段,建立软体臂与被抓抱物运动学和动力学模型。在Python中建立软体臂气动系统、容腔特性、关节运动、软体臂力学特性和控制系统的模型。仿真模拟了在空间环境下,软体臂抓抱目标物的实时工作状态和与动力学交互过程。结果表明,仿真曲线与实验基本一致,验证了仿真的正确性,为软体臂的设计和仿真研究提供了新的思路。

Time of the Tengchong-Lianghe Movement in Southwest Yunnan

The Tengchong-Lianghe movement, proposed and named by Chen et al （ 1991 ）, is an important tectonic event occurred from the late stage of middle Pleistocene to the early stage of the late Pleistocene in the Tenchong Block of southwest Yunnan. It reactivated the old faults in the region, and tilted, folded and fractured the Q1 and Q2 strata, resulting in the common angular unconformity between them. In addition, this region entered into an erosion-cutting stage, with its cutting depth reaching up to tens of meters, and formed very striking high lake terraces.

急性肝胰腺坏死病副溶血弧菌实时荧光RPA快速检测方法的建立

为建立一种简单、快速的急性肝胰腺坏死病副溶血弧菌(VpAHPND)检测方法,本研究根据pirB基因保守序列设计了多组引物和exo探针组合,经过筛选优化,建立了VpAHPND实时荧光RPA检测方法。结果显示,该方法在42℃恒温反应15 min即可快速、特异性地检测出急性肝胰腺坏死病副溶血弧菌(VpAHPND),与其他虾类病原和养殖环境中的致病菌不发生交叉反应,最低菌体细胞检出浓度为3.8×10^(2)CFU/mL,质粒检测限为1.17×10^(1)copies/μL,且具有良好的重复性。利用本研究建立的实时荧光RPA方法与WOAH推荐的实时荧光qPCR方法对50份人工感染的南美白对虾样品进行检测,二者检测结果一致。结果表明,本研究建立的检测方法操作简单,反应灵敏,仪器依赖性低,结果可靠,适用于实验室和现场对VpAHPND快速检测。

2019年度环境地球科学学科项目评审与成果分析

着重分析了2019年度环境地球科学学科各类项目申请受理、评议和资助情况,并指出了申请和评议过程中暴露的问题;总结了2018年底该学科项目结题完成情况以及主要学科方向取得的研究进展。

滇西北剑川盆地新近系地层时代的新认识及构造意义

地处板块接触地带的滇西北剑川地区是研究新构造运动的重要场所。剑川盆地保留有较为完整的新生代地层,在1:250000地质图上,新生界自下而上为古新统勐野井组、始新统宝相寺组、渐新统金丝厂组、中新统双河组和上新统剑川组;其中双河组为一套含可采煤层的砂泥岩夹泥灰岩沉积,剑川组为一套火山-沉积岩组。近期的研究揭示双河组和剑川组均属始新世,但发表的年龄相互包含,并没有清楚的把两者分开。本文采用Ar-Ar和锆石U-Pb方法测试了双河组和剑川组顶、底凝灰岩的年龄,辅以岩体、岩脉的年龄,重新厘定了两个组的顶、底年龄。剑川组顶部凝灰岩锆石SHRIMP U-Pb年龄为34 Ma±;底部凝灰岩黑云母Ar-Ar坪年龄为36 Ma±,与底部侵入岩脉的锆石SHRIMP U-Pb年龄一致;中上部侵入岩脉的黑云母Ar-Ar坪年龄在34~36 Ma之间。同时,老君山岩体、玉召块岩体和沙帽山岩体的锆石SHRIMP U-Pb年龄在34~35 Ma之间。剑川火山-沉积岩组的年龄集中在34~36 Ma之间,属始新世晚期。剑川双河煤矿矿部至三家村及五家村一带,双河组之下新发现一套凝灰岩,其黑云母Ar-Ar坪年龄和锆石SHRIMP U-Pb年龄均为37 Ma±,表明双河组的起始年代不超过37 Ma;双河组形成于36~37 Ma之间,也属始新世晚期。新的结果表明剑川盆地始新统地层应包括宝相寺组、金丝厂组、双河组和剑川组,缺失渐新统沉积。结合其他盆地的年龄数据,表明剑川乃至整个云南地区在渐新世期间为褶皱隆起期。

外源Cl^-添加对不同母质土壤溶液Cd^(2+)浓度的影响

土壤镉(Cd)的环境行为与其在土壤溶液中的存在形态以及陪伴离子有关,然而外源Cl^-与土壤溶液中Cd^(2+)的关系以及不同母质土壤对Cd^(2+)的环境行为的影响并没有明确的结论.选取2种水稻土(第四纪红色黏土母质发育的红黄泥、紫色砂页岩母质发育的紫泥田)为研究对象,添加离子态外源Cd^(2+)(0、1、2.5、5 mg·kg^(-1)),平衡老化后添加外源Cl^-(0、0.6、1.2 mg·kg^(-1)),在保持水分恒定的情况下进行模拟培养试验,研究外源Cl^-添加对土壤溶液Cd^(2+)浓度的影响.结果表明,随着外源Cd^(2+)的增加,土壤溶液Cd^(2+)的浓度提高,红黄泥土壤溶液Cd^(2+)的浓度显著高于紫泥田;添加Cl^-会使土壤溶液中Cd^(2+)浓度升高,且Cd^(2+)浓度与外源Cl^-呈显著正相关,红黄泥和紫泥田土壤溶液中Cd^(2+)的平均浓度比不添加Cl^-时Cd^(2+)的平均浓度分别增加了12.74%、51.49%;土壤对Cd^(2+)的吸附关系符合Freundlich等温吸附方程,紫泥田对Cd^(2+)的吸附量显著高于红黄泥,添加Cl^-对红黄泥Cd^(2+)的吸附影响很小,而对紫泥田的影响显著.Cl^-存在下,红黄泥和紫泥田的解吸率分别为12.50%～19.25%、14.76%～24.99%,外源Cl^-添加对Cd^(2+)解吸影响小.综合分析认为,Cl^-对不同土壤Cd^(2+)的吸附解吸行为影响有较大的差异.

Variations of geochemical compositions and the paleoclimatic significance of a loess-soil sequence from Garzê County of western Sichuan Province,China

The West Sichuan Plateau is located in the southeast margin of the Tibetan Plateau, where the climate is mainly influenced by the Indian southwest summer monsoon and the Tibetan Plateau monsoon. In this study, detailed geochemical analysis has been carried out on Ganzisi loess-paleosol sequence in Ganzê County of western Sichuan Province. The results indicate that Ganzê loess and paleosol have experienced the incipient stage of chemical weathering in dust source regions, characterized by the decomposition of plagioclase which caused the depletion of mobile elements Na and Ca. The post-depositional chemical weathering is characterized by carbonate dissolution and oxidation of Fe2+. The variations of some geochemical indexes (such as CIA values, Na/K and Fe2+/ Fe3+ ratios) in Ganzisi loess-paleosol sequence indicate a gradually decreased chemical weathering intensity in the dust source regions and deposition areas since 1.15 Ma BP consistent with the general increase of global ice volume, reflecting that the arid trend since 1.15 Ma BP in the southeast Tibetan Plateau is a regional response to the global climate change. The geochemical indexes in this section also reveal an obvious drying step occurred at about 250 ka BP in this region. We interpret this drying step as a result of decreased influence of the Indian southwest summer monsoon. This decrease in monsoon moisture is probably attributable to the uplift of the southeast margin of the Tibetan Plateau at about 250 ka BP.