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Paleomagnetic dating of the topmost terrace in Kouma,Henan and its indication to the Yellow River's running through Sanmen Gorges

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Chinese Science Bulletin 2005年第7期50卷 657-664页

作者： PANBaotian WANGJunping GAOHongshan GUANQingyu WANGYong SUHuai LIBingyuan lijijun KeyLaboratoryofWesternChina'sEnvironmentalSystems MinistryofEducationandDepartmentofGeographyLanzhouUniversityLanzhou730000China InstituteofGeographicSciencesandNaturalResourcesResearch ChineseAcademyofSciences(CAS)Beijing100101China KeyLaboratoryofWesternChina'sEnvironmentalSystems MinistryofEducationandDepartmentofGeographyLanzhouUniversityLanzhou730000China

In the east of Xiaolangdi, many river terraces are developed at the exit of the Yellow River Gorges. Among them the terraces in Kouma, Yanshi of Henan Province are most typical, where the Yellow River developed three stair- case terraces, among which the altitude of gravel stratum of the topmost terrace is 30?35 m higher than the river level. The top of the gravel stratum was covered by 60 m eolian loess deposits which have many brownish-red paleosol strips. And the paleosol S14 is at its bottom. Research on systematic magnetostratigraphy and paleosol-loess matching indicates that the bottom age of the loess on the topmost terrace is 1165 ka. Therefore, it can be concluded that the terrace de- velops no later than 1.165 Ma and the situation that the Yel- low River runs through Sanmen Gorges and inpours into East China Sea happened at least before 1.165 Ma.

关键词：河南三门峡黄河发源地地球科学地磁学

Late Glacial and Holocene vegetation history and paleoclimate of the Tengger Desert,northwestern China

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Chinese Science Bulletin 2003年第14期48卷 1457-1463页

作者： MAYuzhen ZHANGHucai H.-J.Pachui B.Wtinnemann lijijun FENGZhaodong NationalLaboratoryofWesternChina'sEnvironmentalSystems CollegeofEarth&EnvironmentSciencesLanzhouUniversityLan-zhou730000China Geolab. InstituteofGeographicalSciencesFreeUniversityofBerlinMalteserStr.74-10012249Berlin.Germany DepartmentofEarthandEnvironmentalStudies MontclairstateUni-versityNJ07043USA

Sediments spanning the last 30000 yr BP wereobtained from two sections in the southern part of the Teng-ger Desert, northwestern China (3810′46″N, 10245′53″E). The pollen assemblage suggested a Picea forest domination under a wetter and cooler environment from 27580 to 23510 yr BP. During the following period from 23510 to 21880 yr BP a Cyperaceae meadow occurred under a wet and coldclimate. Wetter and cooler conditions returned and a Piceaforest re-occupied this region between 21880 and 20910 yrBP. From 20910 to 15590 yr BP a steppe under a dryenvironment dominated the region. The first temperatureincrease started at ca.15590 yr BP. The pollen assemblagecovering the period between 15590 and 10890 yr BP can be divided into six minor zones, suggesting that the vegetation compositions changed rapidly under unstable *** 10710 and 10370 yr BP the climate became cold and dry again. The climatic conditions became warmer and more humid between 10260 and 9140 yr BP. From 8450 to 7950 yr BP a steppe landscape under a dry climate occupied this region. Between 7950 and 7290 yr BP climate seemed more humid. The following period from 7290 to 5670 yr BP wasgenerally warm. The period between 5670 and 3510 yr BPwas characterized by dramatic climatic *** cold intervals appeared around 7760 and 7380,6490—6290, 5670—5010, 4470—3510 yr BP. Twopronounced dry events occurred in 6290—5670 and 5010—4470 yr BP with a marked wet spell from 3510 to 3000 yr BP.

关键词：中国西北地区腾葛尔沙漠古气候全新世晚冰期古植被孢粉学

不同体育锻炼参与程度医护人员心理压力比较研究——以南充市医护人员为例

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当代体育科技 2016年第31期6卷 153-154页

作者：李继军川北医学院体育部四川南充637000

该文通过对南充市200名公立医院医护人员参与体育锻炼程度进行调查,发现医护人员心理压力普遍较大。不同体育锻炼参与程度的三种人群心理压力比较,相对而言经常性参加体育锻炼人群的自我感觉心理压力较小,其次是偶尔参加体育锻炼人群,... 详细信息

该文通过对南充市200名公立医院医护人员参与体育锻炼程度进行调查,发现医护人员心理压力普遍较大。不同体育锻炼参与程度的三种人群心理压力比较,相对而言经常性参加体育锻炼人群的自我感觉心理压力较小,其次是偶尔参加体育锻炼人群,最后是基本不参加体育锻炼人群,由此可以认为医护人员经常性参加体育锻炼有助于缓解心理压力。

关键词：体育锻炼经常性心理压力

Paleomagnetic Excursions Recorded in the Yanchi Playa in Middle Hexi Corridor, NW China Since the Last Interglacial

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Journal of Mountain Science 2004年第2期1卷 128-142页

作者： YANGTaibao YUYongtao lijijun ANCongrong LIUJinfeng ZHANGJunyan KeyLaboratoryofWesternEnvironmentalChanges ChineseMinistryofEducationLanzhouUniversityLanzhou730000China DepartmentofGeography SchoolofGeosciencesNanjingNormalUniversityNanjing210097China InstituteofGeologyandGeophysics ChineseAcademyofSciencesBeo＇ing100029China

Paleomagnetic determinations on lithological profiles of two paralleled[( )-275(long )]drilling cores covering the past 130 kyr B.P., GT40 and GT60, from the Yanchi Playa in the arid Northwestern China, indicate that a series of pronounced paleomagnetic excursions have been documented. By correlating our results with published regional and worldwide reports, 4 excursion events out of 10 apparent reversal signals (labeled from GT-1 to GT-10) were identified as excursion events coeval with the Mono Lake Event ([(28.4)( )]kyr~[(25.8)( )]kyr), Laschamp Event ([(43.3)( )]kyr^40.5 kyr), Gaotai Event (82.8 kyr~[(72.4)25( )]kyr) and the Blake Event (127.4 kyr^113.3 kyr), respectively. GT-9 correlates with the above-mentioned Gaotai Event, GT-7 and GT-6 correspond to two stages of the Laschamp Event and GT-5 to the Mono Lake Event. It is noteworthy that the so-called Gaotai Event has not been reported as a pronounced paleomagnetic excursion in the Northwestern China. Every magnetic excursion event corresponds to paleointensity minima, anteceding those established abrupt paleoclimatic change events, such as the Younger Drays and the Heinrich Events (H1-H6)[(. )-250( )]Here,[( )-250( )]we tentatively[( )-250( )]propose that these geomagnetic excursions/reversals can be viewed as precursors to climate abruptness. During the transitional stages when the earths magnetic field shifted between a temporal normal and a negative period, the earths magnetic paleointensity fell correspondingly to a pair of minima. Although more precise chronology and more convincing rock magnetic parameter determinations are essentially required for further interpretation of their intricate coupling mechanism, these results may have revealed, to some extent, that the earths incessantly changing magnetic field exerts an strong influence on the onset of saw-tooth shaped abrupt climate oscillations through certain feedback chains in arid Central Asia or even North Hemispheric high latitude regions.

关键词： Paleomagnetism geomagnetic excursion the Late Pleistocene arid Northwestern China