Early Cretaceous Climate Changes Recorded in Magnetic Susceptibility and Color Index Variations of the Lower Liupanshan Group, Central China

This study carried out comprehensive analysis on sedimentology, magnetic susceptibility （7of） and color data of the continental sediments of the Liupanshan Group in Central China so as to obtain climatic change information during the 129.14-122.98 Ma interval. Based on the results of the Xlf and of the redness （a＊）, the section can be divided into two segments： （1） 129.14-126.3 Ma, with the lowest Xlf values and strongly variable relatively high values of redness and （2） 126.3-122.98 Ma, with high Elf values and relatively low redness. Analysis of the lithology and facies as well as the magnetic minerals and their contents points to a detrital origin of the magnetic minerals and this allow us to interpret the relationship between magnetic susceptibility variations and climate changes. Our study shows that the climate was significantly dry and hot during the whole studied interval although the interval between 126.3 Ma and 122.98 was a little bit cooler with increased humidity.

Deformation of the Haiyuan-Liupanshan fault zone inferred from the denser GPS observations

The Haiyuan-Liupanshan fault, an active tec- tonic feature at the Tibetan Plateau＇s northeastern bound- ary, was ruptured by two M8 earthquakes （1920 and 1927） bracketing an unbroken section （the Tianzhu seismic gap）. A high seismic hazard is expected along the gap. To monitor deformation characteristics and do a seismic risk assessment, we made measurements at two newly built campaign-mode Global Positioning System （GPS） stations and 13 pre-existing stations in 2013 and 2014. Adding existing data from 1999 to 2014, we derived a new velocity field. Based on the horizontal velocity, we used three block models to invert the deformation of four crustal blocks. The results suggest non-uniform deformation in the interior of the Lanzhou block, the Ordos block and the Alaxan block, but uniform deformation in the Qilian block. Fault slip rates derived from block models show a decreasing trend from west to east, （2.0-3.2 mm/a on the Haiyuan fault to 0.9-1.5 mm/a on the Liupanshan fault）. The Haiyuan fault evidences sinistral striking-slip movement, while the Liupanshan fault is primarily thrusting due to transformation of the displacement between the strike-slip and crustal shortening. The locking depth of each seg- ment along the Haiyuan fault obtained by fitting the fault parallel velocities varies drastically from west to east （21.8-7.1 km）. The moment accumulation rate, calculated using the slip rate and locking depth, is positively corre- lated with the locking depth. Given the paucity of large seismic events during the previous millennium, the Tuo- laishan segment and the Maomaoshan segment have higher likelihood of nucleation for a future event.

THE ENVIRONMENTAL QUALITY AND RENOVATING PLAN OF THE LOESS PLATEAU AND LIUPANSHAN MOUNTAINOUS AREA IN NINGXIA

1. The environmental quality of the Loess Plateau and Liupanshan mountainous area in Ningxia The landuse structure in the studied region was very irrational in 1970s, the propor-tions covered by farming, forestry and animal husbandry are separately 50.91%, 6.32% and33.3%. Since 1980s, the farmland has been returned back to forestry and pasture so that

Palynological assemblage in the late Early Cretaceous from Sikouzi Section, Liupanshan Group, Central China and its implication to paleoenvironment change

The Cretaceous(ca.145 Ma^65 Ma)was characterized by remarkable greenhouse conditions which was more server than present greenhouse gas emissions.However,this special climate condition is mainly documented from marine records.The information derived from continental sediments including terrestrial vegetation is relatively scarce.Here,we report on a palynological study of 17 samples from the Lower Cretaceous Liupanshan Group of the Sikouzi Section(spanning116 Ma^103 Ma),Liupanshan Basin and analyzed for paleoclimate implications.The palynoflora is diverse,dominated by Classopollis(Cheirolepidiaceae),with abundant ferns and rare angiosperms.The dominant ferns are from Lygodiaceae and Schizaeaceae.The palynological data shows that the Early Cretaceous floras are derived from various settings,i.e.,the Coniferales on high elevation mountains,Cheirolepidiaceae along low hills near lakes,ferns in marsh wetlands,and algae in fresh water lakes.The palynoflora indicates that the climate in the Liupanshan area is hot and dry,and the palaeogeography is characterized by complex and various outlook during the Early Cretaceous,furthermore,climate evolution revealed by the vegetation can be divided into two stages during this period.From 116 Ma to 112 Ma,the concentration of thermophilic and xerophilous species such as Cheirolepidiaceae and Schizaeaceae were relatively low,conifers increased significantly,and fern concentration remained steady.This ecosystem suggests a humid and cold climate during this period.From 112 Ma to 103 Ma,the concentration of Cheirolepidiaceae and Schizaeaceae was relatively high,and conifers decreased significantly.Compared to the upper stage,the total percentage of Lygodiaceae spores were relatively low.Vegetation change during this period may indicate an increased trend of a dry and hot environment in this region.The trend of climate change recorded by the pollen assemblages during this period coincide with global sea surface temperature fluctuation.Thus,climate change recorded by the palynological assemblage in the Sikouzi section correlates well with global climate change during the Early Cretaceous.

Study on Paleoearthquakes of the Eastern Liupanshan Piedmont Fault Zone

Based on trench excavation and detailed field investigation, the authors have ascertained that 6 paleoearthquake events have occurred in the Haizixia area of the Eastern Liupanshan Piedmont fault zone since 46Ka B.P. The recurrence time of 6 events were about 15000a, 20250a, 14750a, 12150a, 8550a and 4000a B.P., respectively, the recurrence intervals were about 15000a, 5500a, 2600a, 3600a and 4550a, respectively. According to M-D empirical relations, the vertical dislocation of events 1 and 2 corresponded to the dislocation of the earthquake with M8.0; the vertical dislocation of events 3-6, was corresponded to the dislocation of earthquakes with M6.5~7.5.

Provenance Analyses of Lower Cretaceous Strata in the Liupanshan Basin: From Paleocurrents Indicators, Conglomerate Clast Compositions, and Zircon U-Pb Geochronology

The Liupanshan Basin constitutes a major portion of the northern North-South tectonic belt. The Lower Cretaceous strata in the Liupanshan Basin recorded the tectono-sedimentary evolution processes of this area and are pivotal for understanding the original sedimentary appearance of the Liupanshan Basin. In this work, we present a study of provenance and tectono-sedimentary evolution of the Liupanshan Basin during the Early Cretaceous. Integrated-paleocurrent directions, gravel clast compositions, and detrital zircon U-Pb isotopic analysis of the Lower Cretaceous Sanqiao and Heshangpu formations were applied to determine the provenance. The gravel clast compositions of Sanqiao Formation conglomerates(mainly including magmatic rocks, metamorphic rocks and limestones) display various features in different places, revealing different rock components of source areas. The paleocurrent directions of the Sanqiao and Heshangpu formations suggest that the sediments were transported from the basin margin to the center. Detrital zircons of two samples from the Huoshizhai Section(northwestern Liupanshan Basin) yield a dominant unimodal distribution from 420 to 500 Ma, suggesting a single-sourced provenance. Based on the above analyses, comparing to the magmatic records in the Qilian-Qinling orogenic belt, the detritus of the Sanqiao and Heshangpu formations were mainly from the proximal metamorphic and magmatic rocks of the Qilian-Qinling orogenic belt and the limestones of the archaic uplift. Combined with sedimentary characteristics, we concluded that the Liupanshan Basin experienced multi-stage evolution history:(1) the early rifting extension stage(Sanqiao Period),(2) the middle spanning and depression stage(Heshangpu–Early Naijiahe Period), and(3) the late extinction stage(Late Naijiahe Period). The evolution of Liupanshan Basin is closely related to that of Ordos Basin and it is further associated with tectonic transition of the northern North-South tectonic belt.

Exceptionally Preserved Caddisfly Larval Cases(Insecta) from the Lower Cretaceous of the Liupanshan Basin, Western China

Abundant well-preserved tubular fossils of caddisfly （Insecta： Trichoptera） larval cases are reported from the Early Cretaceous Madongshan and Naijiahe formations of the Liupanshan Basin, Ningxia Province, western China. Most cases were mainly preserved in life position and densely packed in various layers. Individual cases in each layer tended to be same in size and were erect and parallel to one another and open at both ends. In a transverse section cut perpendicular to the long axis of the cases, individual case appears to form a rounded ring. Small cases are elliptic in a cross-section oblique to the long axis of the cases. Tube walls are nearly subparallel to one another in longitudinal section with both ends being open. The caudal end of the case slightly tapers and usually points downward. The cases were closely packed, almost touching with one another and lacking bifurcate or connecting struc- ture. The overwhelming majority of cases were partially or fully filled with calcite. The case wall em- braces a medium particle layer flanked by inner and outer organic layers. Individual particles are ovate in outline and comprise cryptocrystalline or ganic pellets. SEM imaging shows that those pellets are sub-cylindrical in outline and elliptic in cross section, and are made primarily of calcium carbonate. All features observed justify the assignment of the Liupanshan caddisfly cases to ichnogenus Coprindusia. The extinct insect Ningxiapsyche fangi was found in association with the Liupanshan caddisfly larval cases, and thus could be the candidate of the potential trace-maker.

New knowledge of the Upper Triassic in Liupanshan Basin,Ningxia,China

Based upon the new data of spore pollen, plant and bivalve fossils, the coal bearing strata in the Liupanshan Basin, Ningxia Hui Autonomous Region, Northwest China, which were formerly assigned to the Middle Jurassic Yan’an Formation, are divided into two parts in the present study. The major part is assigned to the Upper Triassic and the overlying part remains in the Jurassic. The new division is of significance to the oil gas exploration of the basin and the interpretation of the sedimentary and tectonic history and the geographic environment of Liupanshan area during the early Mesozoic.

毛泽东《清平乐·六盘山》译者群体行为研究

20世纪50年代末,毛泽东诗词被译成多种文字在全世界广泛传播,涌现出不同的译者群体。然而,译者作为翻译的主体,却一直未受到足够的重视。本文以译者行为批评理论为指导,聚焦毛泽东《清平乐·六盘山》一词,将翻译此词的译者视为同一译者群体,从翻译外和翻译内两个层次出发,全面地、客观地分析同一译者群体的不同译者在两个翻译层次上行为的共性和个性,从而提升这一理论的实践指导价值,以进一步指导和阐释翻译实践。

六盘山盆地构造变形分析:来自地震剖面的约束

六盘山盆地先后经历早古生代克拉通碳酸盐岩台地、古生代海陆交互、中生代内陆湖盆等过程,发育石炭系、三叠系—侏罗系和白垩系3套烃源岩,是当下可拓展的油气有利区之一。但是,该盆地所处大地构造位置特殊,受青藏高原、阿拉善、鄂尔多斯等块体相互作用,经历多期构造运动,发育大量褶皱与断裂等构造,地壳结构及盆地属性经历强烈改造,在一定程度上制约了六盘山盆地油气资源评价和有利区带优选。基于此,选择六盘山盆地3条关键地震剖面,结合野外构造变形特征和钻井信息,讨论了六盘山盆地中生代以来多期构造事件下的盆山演化过程,主要包括中生代早期(三叠纪/侏罗纪)局部伸展断陷,早白垩世早期挤压与晚期伸展,新生代以来受青藏高原增生扩展,六盘山地区强烈挤压,造就了现今六盘山褶皱逆冲带。

六盘山地形及相对湿度对微波辐射计反演气温的影响

利用2018年4月至2019年11月的六盘山隆德站微波辐射计探测资料与平凉站探空资料,研究了微波辐射计反演温度(TM)对空气相对湿度的敏感性。首次提出湿度敏感性系数(HSR)和零度漂移度(ZDD)概念,利用这两个参量在不同高度层的分布特征,研究了六盘山地形对空气相对湿度和温度的影响,主要结论如下:(1)非降水天气条件下,空气相对湿度越大,HSR与1.0的差别越大,ZDD也越大。(2)六盘山地形对大气层的湿度垂直分布影响较大。爬坡气流或抬升气流明显增加了3 km以下气层湿度水平,晴天和阴天条件下空气相对湿度分别在山顶以上0.5 km气层和1.0~2.0 km气层达到最大,TM比实际温度最大能偏低2.7℃。(3)地形对气层湿度的影响进一步影响了空气温度的垂直分布,阴天条件下的大气逆辐射加热使得3 km以下气层平均升温2.3℃,因湿度敏感性产生的温度影响平均达到0.9℃,最高能达到1.7℃。

世界非物质文化遗产六盘山花儿理论创新概述

六盘山花儿口头文学是国家级非物质文化遗产,也是联合国教科文组织认定的人类非物质文化遗产,是西北花儿的三大体系之一。研究六盘山花儿口头文学可以促进民族文化团结,推动中华优秀传统文化的发展。笔者在对六盘山花儿的理论研究成果进行搜集和整理的过程中发现,以卜锡文、屈文焜、武宇林等为代表的六盘山花儿研究近年来正在逐渐走向深入,研究成果丰硕,涉及语言文学艺术、音乐学和文化领域。本研究重点分析了三位学者对六盘山花儿的历史贡献和理论研究成果以及三位学者提出的观点,有助于我们从文学角度进一步深入思考和研究。

综合物探方法在六盘山盆地月亮山地区铀矿勘查中的应用

六盘山盆地含有丰富的矿产资源,开展过铀矿找矿工作,曾发现多个铀矿点和铀异常点。由于铀矿具有隐伏性强、成矿地质条件复杂、矿化特征不易发现等特征,给找矿工作带来巨大困难。不同的物探方法可以识别不同的物性差异,利用多种物探方法相结合的勘查手段进行综合分析,给铀矿勘查工作提供重要信息和依据。为进一步研究六盘山盆地月亮山区域成矿条件,基于该地区铀矿地质成矿条件,在前人工作基础上,在该地区重点地段开展了综合物探测量工作。通过开展音频大地电磁法、高精度磁测和土壤氡气测量3种物探测量方法,大致查明了研究区主要断裂的位置、深度和发育特征,确定了基底埋深情况,综合分析区域铀矿化特征和成矿条件。通过音频大地电磁测量和高精度磁测工作,初步确定了研究区内的基底埋深情况,大致查明了研究区主要断裂发育特征;通过高精度磁法测量推断研究区磁异常大小与沉积物厚度相关,盖层越厚,基底越深,其地表磁异常越大;盖层越薄,基底越厚,其地表磁异常越小;通过土壤氡气面积测量,在盆地内部发现了2片土壤氡气异常区。上述结论为后期的地质和钻探工作提供了重要的物探依据。

宁夏固原六盘山机场的昆虫多样性

【目的】机场飞行区昆虫的多样性是诱使鸟类进入的重要原因,因此昆虫资源调查是预防鸟击事件的重要环节。【方法】2020年7~9月在宁夏固原六盘山机场飞行区采用灯诱法、样线法和陷阱法开展昆虫资源调查。【结果】共采集到28 430头昆虫标本,隶属于8目61科126属145种,其中以鞘翅目Coleoptera、膜翅目Hymenoptera和双翅目Diptera为优势类群,物种数占比分别为41.38%(60种)、8.28%(12种)和13.10%(19种),个体数占比分别为68.79%、11.88%和11.56%。不同月份多样性分析表明,Shannon-Wiener指数表现为:9月份>8月份>7月份;Margalef丰富度指数表现为:8月份>9月份>7月份;Berger-Parker优势度指数表现为:7月份>8月份>9月份;Pielou均匀度指数9月份>7月份>8月份。【结论】固原六盘山机场飞行区7月份昆虫物种多样性最低,昆虫种类最简单,生态位优势类群优势地位最突出;8月份昆虫种类最丰富,但均匀度最低;9月份昆虫多样性最高,生态位优势类群优势地位最低,种间数量分布最均匀。不同月份昆虫群落为中等不相似,相似系数介于0.25~0.50。

六盘山盆地新生界沉积微相与沉积演化

为研究六盘山盆地新生界沉积微相特征与沉积演化规律,以盆地周缘野外露头岩性、沉积构造与沉积微相特征为研究对象,对六盘山盆地新生界沉积微相与沉积演化进行研究。结果表明,六盘山盆地新生界发育始新统寺口子组、渐新统清水营组、中新统彰恩堡组与干河沟组,与下伏不同时代地层不整合接触;六盘山盆地新生界沉积相为冲积扇、辫状河、三角洲、湖泊及沙漠沉积;根据砂、泥沉积在纵向上的组合特征,识别出砂泥薄互层式、厚泥厚砂式、薄泥厚砂式、厚泥薄砂式4种沉积充填样式;受青藏高原隆升的影响,六盘山盆地填充初始期寺口子组以辫状河冲积扇为主,在横向和纵向上变化较大,高峰期清水营组蒸发强烈,以膏盐等碎屑岩为特色的湖相沉积为主,衰退期彰恩堡组南部以湖相为主,北部以河流相为主,消亡期干河沟组自下而上砾石增多,以河流相为主,整个新生界沉积微相反映了六盘山盆地新生代沉积演化过程。研究结果对六盘山盆地新生界沉积微相与沉积演化规律有了新认识,也为不同层位、不同沉积盆地的研究提供借鉴。

软岩中TBM停机状态下岩机相互作用规律研究

在软岩环境下使用TBM施工时,遇卡机等事故处理和设备检修更换常需TBM停机,预留变形量和停机时间是TBM安全运行的关键。依托白龙江引水工程六盘山泥岩隧洞,根据实际地质条件、隧道结构和TBM施工流程,采用数值计算的方法研究了TBM停机状态下围岩的变形特征及其与护盾的相互作用,并分析了合理的预留变形量和停机时间。结果表明:①该工程砂质泥岩为极软岩,流变性显著且服从Cvisc和Burgers模型,预留足够的变形量和快速掘进可保证TBM安全通过;②在停机期间,围岩变形具有显著时空效应,变形先快后慢,垂直位移大于水平位移,护盾后部围岩位移大于前部;③岩机相互作用的时空效应表现为,自下而上、由后至前,相继经历无接触-局部接触-完全接触-强烈挤压的过程;④预留变形为10 cm时的TBM安全停机时间不宜超过7 d。研究成果对认识软岩中TBM停机期间岩机相互作用具有理论参考意义。

六盘山雨滴谱降水数据的Z-R关系研究

利用2021年5—10月六盘山站观测的分钟雨滴谱数据,结合六盘山自动气象站观测资料,选择46次降水过程,对六盘山气象站降水的雨滴谱分布、物理特征及雷达反射率因子Z和降水强度R的关系进行分析研究,拟合得到适用于六盘山站降水过程的Z-R关系。结果表明:Z=175R1.6关系式可以较好地描述六盘山站降水情况,降水强度随着雷达反射率因子增大而增大;当降水强度增大时,估测降水量的误差会随之偏大。利用Z=175R1.6估算的六盘山站的降水量接近自动气象站实测降水量,二者相关性较高。

当代六盘山题材青绿山水画创作研究

青绿山水源远流长,在中国画中具有举足轻重的地位。青绿山水画在历史上虽几经兴衰,但由于其独特的艺术魅力而延续至今。随着时代的发展,青绿山水画在选材、创作等方面呈现出不同的特点。六盘山具有深厚的历史文化底蕴,自古以来就是文人墨客创作的源泉,并取得了丰富的成果。本文通过对当代六盘山题材青绿山水画艺术语言、创作特点等方面的考察,以期为丰富相关题材青绿山水画的创作提供参考价值。

六盘山东麓活动逆断裂构造带晚第四纪以来的活动特征

新的野外调查研究结果表明，六盘山东麓断裂是一条第四纪以来的活动逆断裂构造带。根据断裂走向、活动时代及活动性质的变化，可把该断裂带分为北、中、南３段。北段以左旋走滑运动为主，中、南段以倾向逆冲运动为特征。活动时代北新南老，水平位错北强南弱。晚第四纪以来断裂活动特征的这种变化与西华山六盘山条形地块东向滑移受阻及断裂走向的改变有关。

鄂尔多斯盆地西部晚三叠世原型盆地恢复及其改造演化

恢复鄂尔多斯晚三叠世原型盆地是评价盆地西缘上三叠统油气勘探前景的重要问题。研究认为,在三叠纪延长组沉积期,鄂尔多斯盆地西部受秦祁褶皱带和阿拉善古陆控制,六盘山西缘大断裂和贺兰山西缘断裂分别构成晚三叠世沉积盆地的西南与西北边界;走廊过渡区与盆地本部沉积具有连通性,形成向西开口、南深北浅、主体为北西-南东向的大型不对称坳陷盆地,银川盆地、六盘山盆地是鄂尔多斯盆地的一部分,盆地西缘前人所称的“南北古脊梁”不起沉积分割作用。延长组沉积期湖盆西部从南到北发育汭水河—镇原、景泰—环县、窑山—甜水堡和汝箕沟—盐定4个三角洲沉积体系,受不同物源影响,各体系沉积特征不同,并且经后期构造运动改造,在盆地西缘冲断带上盘残存不全。但在现今冲断带以东及其掩覆地区延长组保存较完整,延长组残余沉积分布广泛,勘探前景广阔。