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Early Pleistocene formation of the asymmetric east-west pattern of upper water structure in the equatorial Pacific Ocean

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Chinese Science Bulletin 2011年第21期56卷 2251-2257页

作者： JIN HaiYan JIAN ZhiMin CHENG XinRong guo JianQing State Key Laboratory of Marine Geology Tongji UniversityShanghai 200092China

Surface-and subsurface-dwelling planktonic foraminifera from the upper 43 m of Hole A at the Ocean Drilling Program (ODP) Site 807,which was recovered from the western Pacific warm pool during ODP Leg 130,were analyzed for stable oxygen and carbon *** comparing these results with data from ODP Site 851 in the eastern equatorial Pacific,this study has reconstructed the paleoceanographic changes in upper ocean waters in the equatorial Pacific since 2.5 *** the period from 1.6-1.4 Ma,the oxygen isotopes of surface and subsurface waters were found to markedly change in the western and eastern equatorial Pacific,further confirming the final formation of the well-defined asymmetric east-west (E-W) pattern at that *** feature was similar to the zonal temperature gradient (sea surface temperature is higher in the west and lower in the east) and the asymmetric upper water structure (thermocline depth is deeper in the west and shallower in the east) in the modern equatorial *** zonal gradient change of subsurface water δ18O was greater than that of surface water δ18O,indicating that the formation of the asymmetric E-W pattern in the equatorial Pacific should be much more related to the shoaled thermocline and markedly decreased subsurface water temperature in the eastern equatorial ***,since ～1.6 Ma,the carbon isotopic differences between surface and subsurface waters clearly decreased in the equatorial Pacific,and their long-term eccentricity periods changed from 400 ka to ～500 ka,reflecting the reorganization of the ocean carbon *** probably resulted from the deep water reorganization in the Southern Ocean at that time and its enhanced influence on the tropical Pacific (especially subsurface water).Our study demonstrates that the tropical ocean plays an important role in global climate change.

关键词：赤道太平洋非对称早更新世结构模式上层水体碳同位素分析大洋钻探计划

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Upper Jaramillo polarity transition and short geomagnetic event recorded in a loess section at Jingbian, northern China

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Chinese Science Bulletin 1999年第20期44卷 1907-1914页

作者： Bin guo Rixiang Zhu Zhongli Ding Jiming Sun Chinese Acad Sci Inst Geophys Beijing 100101 Peoples R China Chinese Acad Sci Inst Geol Beijing 100080 Peoples R China

Detailed rock-magnetic and paleomagnetic investigations have been carried out in a loess-paleosol sequence from the lower part ot unit S9 to the bottom of L11 at Jingbian (37.4° N, 108.8°E), which demonstrates that the Upper Jaramillo polarity reversal and a short geomagnetic event bounded within the Jaramillo normal subchron have been revealed. The duration of this short event was about 8.5 ka. The statistical analysis showed that the virtual geomagnet-

关键词： Upper Jaramillo short geomagnetic event loess Jingbian.

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Clay minerals in the late Quaternary sediment of Tulare Lake,California: Implications for climate change, weathering, and erosion processes

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International Journal of Sediment Research 2019年第5期34卷 432-443页

作者： Junhua guo Christine Pyles William Krugh Rob Negrini Department of Geological Sciences California State UniversityBakersfield

The clay mineralogy of Tulare Lake sediment was examined to investigate hydroclimatic and environmental changes in the southern Sierra Nevada Mountains(SNM) since the most recent glacial *** of clay mineral assemblages elucidates significant changes in weathering, erosion, and hydroclimatic condition in the catchment. During the last glacial period(24.4–15.1 cal ka BP), low illite content implies less physical erosion of the granitic batholith rocks and a cold and arid environment in the southern SNM. Abrupt increases of illite content at 21.8–20.8 and 17.6 cal ka BP resulted from the glacier advances to the ablation zone and illite-rich glacier flour was transported down to the lake. The gradual increase of smectite induced by progressive depletion of illite-rich glacier flour from 17.6 cal ka BP toward the end of this period indicates climate was beginning to get warm and wet. From 11.9 to5.3 cal ka BP, two warm and wet periods(10.7–9.4 and 8.2–5.2 cal ka BP) were characterized by high smectite/illite content ratios and low illite crystallinity values, suggesting intensive rainfall precipitation and more physical erosion in the highland and lowland catchment as well as more smectite formation in the terrace soils. Since the last glacial period, physical erosion, in comparison to the chemical weathering,was the dominant process responding to the hydroclimatic change in the Tulare Lake *** to weak chemical weathering was signified by the mostly low illite chemical weathering index of the core sediments. Such results suggest that vegetation cover in the southern SNM was low and limited.

关键词： Clay mineralogy Sierra Nevada Mountains Glaciers Weathering Tulare Lake

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Age and Provenance of Loess deposits on the Northern Flank of Tianshan Mountain

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Acta Geologica Sinica(English Edition) 2009年第3期83卷 648-654页

作者： YUAN Qingdong ZHANG Zhicheng WU Chaodong guo Zhaojie Key Laboratory of Orogenic Belts and Crustal Evolution （Peking University） Ministry of Education Beijing 100871 China

The distribution, optically stimulated luminescence dating and granulometric properties suggest that the loess on the northern flank of Tian Shan should be divided into two types. One which is like mantle and is named type A, is located on the windward slopes and dated to about 54.5±5.73 ka. The other, called type B, lies flatly on the terraces of the rivers or low hills and penetrated 30.8±2.05 ka ago. Here we study the origin and the age of two types of loess, and a model of loess formation is proposed. The dust was entrained from the Gobi Desert located to the north of Tian Shan by the monsoon from Mongolia, obstructed by the high mountains and deposited on the windward slopes of the mountains. The rivers and flows then transported the aeolian loess to low terraces and piedmont alluvial plains.

关键词： loess optically stimulated luminescence dating granulometric properties North Tianshan

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Cyclostratigraphy of the Induan (Early Triassic) in West Pingdingshan Section,Chaohu,Anhui Province

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Science China Earth Sciences 2008年第1期51卷 22-29页

作者： guo Gang TONG JinNan ZHANG ShiHong ZHANG Jie BAI LingYan GPMR and BGEG Laboratories at China University of Geosciences Wuhan 430074China School of the Earth Sciences and Resources China University of GeosciencesBeijing 100083China

The Induan sequence in the West Pingdingshan Section, Chaohu, Anhui Province, displays a series of superimposed mudstone/limestone cycles. The lithological character of the cycles, combined with power spectral and wavelet analysis of magnetic susceptibility readings, reveals 12 short eccentricity and 56 precession Milankovitch cycles - obliquity cycles are not apparent. The uniformity of cycle thicknesses indicates a stable depositional setting making this section ideal to perform various geo-logical studies. Accordingly, the Induan Stage is estimated to have lasted 1.1 Ma, and the depositional rate for this part of the section is about 3.7 cm/ka. This places the Induan-Olenekian boundary in the West Pingdingshan Section at about 251.5 Ma based on an age of 252.6 Ma for the Permian-Triassic boundary.

关键词： Induan cyclostratigraphy magnetic susceptibility spectral analysis wavelet analysis Chaohu Anhui Province

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Quaternary glacial geomorphology and glaciations of Kongur Mountain,eastern Pamir,China

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Science China Earth Sciences 2011年第4期54卷 591-602页

作者： WANG Jie ZHOU ShangZhe ZHAO JingDong ZHENG JingXiong guo XiangZhong MOE Key Laboratory of Western China's Environmental System Lanzhou University Lanzhou 730000 China Geographical Science College South China Normal University Guangzhou 510631 China State Key Laboratory of Cryospheric Sciences Cold andArid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China

Kongur Mountain is the largest center of modern glaciation on the Pamir *** the glacial-interglacial cycles of the Quaternary,Kongur Mountain was extensively and repeatedly glaciated,and the glacial landforms from multiple glaciations are well-preserved in valleys,in basins,and on the *** samples have been collected according to the distribution and weathering of the glacial tills,the relationship among the glacial deposits,and the loess or soil developed on the moraines. Electron spin resonance(ESR) dating of the samples was done using the germanium(Ge) centers in the glacial quartz grains,which are sensitive to both sunlight and *** ages of the glacial deposits can be divided into four clusters,i.e.,13.1±0.8-27.0±2.2,36.4±3.3-48.7±5.7,65.6±6.8-86.6±8.9,and 105.6±9.4-178.3±17.8 *** glacial advances in this region have been confirmed,which are equivalent in age to the Little Ice Age(LIA) ,Neoglaciation,marine oxygen isotope stages(MIS) 2,mid-MIS3,MIS4,and *** largest local last glacial maximum(LGML) occurred during MIS4 rather than the global Last Glacial Maximum(LGMG) of MIS2,and a glacial advance that occurred during mid-MIS3 was also larger than the ***,deeply weathered tills below 3500 m *** the western slope of Kongur Mountain,when compared with the ages of the oldest glaciation of the Muztag Ata region,likely occurred prior to the penultimate glacial *** glacial landforms prior to the penultimate glacial cycle on the northern slope are not well-preserved due to erosion after deposition. Several glacial deposits are only speculated to be distributed at higher elevations on the southwest side of the Gaizi Checkpoint. The extensive hummocky moraines on the western slope were formed by multiple glacial advances,and the latest glacial advance corresponded to mid-MIS3.

关键词： Kongur Mountain glacial geomorphology ESR dating Quaternary glaciation hummocky moraine

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Revisiting the dependence of thermocline-dwelling foraminiferal B/Ca on temperature and [CO32-], and its application in reconstruction of the subsurface carbonate system in the tropical western Pacific since 24 ka

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Acta Oceanologica Sinica 2019年第9期38卷 71-86页

作者： Jingteng guo Tiegang Li Zhifang Xiong Xiaohua Qiu Fengming Chang CAS Key Laboratory of Marine Geology and Environment Institute of Oceanology Chinese Academy of Sciences Qingdao 266071 China First Institute of Oceanography Ministry of Natural Resources Qingdao 266061 China University of Chinese Academy of Sciences Beijing 100049 China Laboratory for Marine Geology and Environment Pilot National Laboratory for Marine Science and Technology (Qingdao) Qingdao 266237 China No. 1 Institute of Geology and Mineral Resources of Shandong Province Jinan 250014 China

The B/Ca ratio of planktonic foraminifer shells has been used as a proxy for reconstructing past ocean carbonate chemistry. However, recent studies have revealed significant uncertainties associated with this proxy, such as whether seawater temperature or [CO^2-3 ] is the dominant control on the partition coefficient (KD) of planktonic foraminiferal B/Ca. To address these uncertainties and thus improve our understanding of the planktonic foraminiferal B/Ca proxy, we analysed B/Ca ratios in the tests of Neogloboquadrina dutertrei (300- 355 μm) and Pulleniatina obliquiloculata (355- 400 μm) in surface sediment samples from the tropical western Pacific and South China Sea. The relationship between these B/Ca ratios and bottom water calcite saturation states (Δ[CO^2-3 ]) is weak, thus suggesting only a small dissolution effect on the B/Ca of the two species. The correlation coefficients (R2) between the B/Ca ratios of N. dutertrei and P. obliquiloculata and environmental parameters (e.g., temperature, salinity, phosphate, DIC and ALK) in the tropical western Pacific and South China Sea are not high enough to justify using B/Ca ratios as a palaeoenvironmental proxy in the study areas. The significant correlation between KD values of N. dutertrei and P. obliquiloculata and carbonate system parameters (e.g.,[CO^2-3 ], DIC, ALK, pH and [HCO^-3 ]) in the study area reflect chemical links between the KD denominator and these variables. Based on our surface sediment calibration, an empirical relationship between the KD of N. dutertrei and temperature is proposed in the tropical western Pacific. We also generated a record of B/Ca ratios in N. dutertrei (300 -355 μm) from Core MD06-3052 in the tropical western Pacific over the past 24 ka to evaluate the application of the revised B/Ca proxy method. Based on the reconstructed empirical relationship for B/Ca and subsurface seawater ALK, we estimated subsurface seawater carbonate system parameters in the tropical western Pacific si

关键词： planktonic foraminifera B/Ca carbonate chemistry tropical western Pacific South China Sea

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Optically Stimulated Luminescence(OSL) Chronology of the Dehenglong Landslide from Longyang Gorge to Liujia Gorge along Upper Yellow River, China

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Acta Geologica Sinica(English Edition) 2015年第1期89卷 242-250页

作者： guo Xiaohua LAI Zhongping LU Yudong LI Xiaolin SUN Zheng Key Laboratory of Subsurface Hydrology and Ecological Effect in Arid Region of Ministry of Education School of Environmental Science and Engineering Chang'an University School of Earth Sciences China University of Geosciences Key Laboratory of Environmental Geology of Qinghai Province Qinghai Provincial 906 Qinghai Institute of Geological Investigation

Giant landslides are common along the upper Yellow River from Longyang Gorge to Liujia Gorge, and some of them even blocked and dammed the upper Yellow River. Chronology is inevitable in studying the mechanism of giant landslides. Controversy exists about the chronology of those giant landslides, and some have not yet dated. The Dehenglong landslide is the largest one among them. In this study, OSL samples were collected from lacustrine silty sediments and loess directly overlying the landslide sediments, as well as fault sediments related to the landslide. This landslide yielded an age of 89 ±8 ka, which is identical with the fault age of 73 ±5 ka at two sigma errors. The agreement of a topographic analysis and the absolute age of landslides imply that the formation of the Dehenglong landslide is strongly correlated with the tectonic activity.

关键词： landslide OSL Upper Yellow River in China Qinghai-Tibetan Plateau

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单辊快速凝固法制备Co-Cu-Pb合金颗粒的结构与形成机制

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粉末冶金材料科学与工程 2016年第6期21卷 862-869页

作者：高卡郭晓琴张锐郑州航空工业管理学院航空材料河南省重点实验室郑州450015 郑州大学材料科学与工程学院郑州450001

摘要：分别以Co47.5Cu47.5Pb5和Co42.5Cu42.5Pb15三元偏晶合金作为母合金，采用单辊法急冷快速凝固制备Co—Cu—Pb三元难混溶合金颗粒，对颗粒的微观组织结构与尺寸进行观察与分析，并对不同结构颗粒的形成机制进行研究。结果表明：Co-C... 详细信息

摘要：分别以Co47.5Cu47.5Pb5和Co42.5Cu42.5Pb15三元偏晶合金作为母合金，采用单辊法急冷快速凝固制备Co—Cu—Pb三元难混溶合金颗粒，对颗粒的微观组织结构与尺寸进行观察与分析，并对不同结构颗粒的形成机制进行研究。结果表明：Co-Cu-Pb合金颗粒的直径为70～600μm，得到实心颗粒、空心颗粒及多层壳核结构3种不同结构的颗粒。Co-Cu-P合金颗粒发生包晶反应形成富Co（Cu）相的初生枝晶，富Pb相主要富集于枝晶间隙处。随辊面线速度从15m／s增大到30m／s，初生Co（Cu）相枝晶发生粗大枝晶→细小等轴晶的转变，合金颗粒的凝固组织显著细化，并且由于液态难混溶合金发生Marangoni运动，形成快速凝固多层壳核结构，最终获得均质化的Co-Cu-P合金凝固组织。

关键词：金属材料 Co-Cu-P合金颗粒快速凝固壳核结构组织形态形成机制

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高压输电线铁塔采动损害与保护技术现状及展望

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煤炭科学技术 2011年第1期39卷 97-101,106页

作者：郭文兵邓喀中河南理工大学能源科学与工程学院河南焦作454000 中国矿业大学环境与测绘学院江苏徐州221008

为了全面了解采动影响下高压输电线铁塔变形特征,解决煤矿面临的高压输电线铁塔压煤开采问题,从地表沉陷控制研究、高压输电线路铁塔下采煤实践、采动对高压输电线路及铁塔影响、高压输电线路铁塔保护技术等方面,总结分析了国内外高压... 详细信息

为了全面了解采动影响下高压输电线铁塔变形特征,解决煤矿面临的高压输电线铁塔压煤开采问题,从地表沉陷控制研究、高压输电线路铁塔下采煤实践、采动对高压输电线路及铁塔影响、高压输电线路铁塔保护技术等方面,总结分析了国内外高压线铁塔采动损害与保护技术的研究现状。分析结果表明:高压输电线路铁塔不是单一孤立的构筑物,而是由地基、基础、铁塔结构和导线等组成的空间结构体系,其变形规律与一般高耸建(构)筑物存在差异,现有采动区建(构)筑物损害评价及保护理论不适合。指出应研究建立基于地基基础、铁塔结构、线路协同变形理论的高压线铁塔下采煤安全防护理论和技术措施。

关键词：采动损害与保护高压输电线路铁塔三下采煤协同变形理论

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