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.

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。

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。

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.

联合GPS和InSAR研究海原-六盘山断裂现今的地壳变形特征

海原—六盘山构造区为青藏高原东北部构造变形最为显著的区域之一,历史强震活动频繁,是研究青藏高原NE向扩展的重要窗口和地震孕育过程的理想场所。文中处理了跨海原-六盘山断裂2014—2020年期间2个轨道的时序Sentinel-1A/B SAR数据,获得了该区域InSAR视线向现今的地壳形变场。融合公开发表的近十多年时间尺度的水平GPS地壳运动速度场,获得了研究区高密度地壳水平形变场。对比GPS、水准和InSAR观测结果,以及GPS-InSAR融合的高密度水平形变场,分析讨论了该区域的地壳形变、应变场特征及其与构造之间的对应关系。主要结论如下:1)GPS和InSAR观测表明,1920年海原8.5级大地震的震后黏弹性松弛效应在海原断裂南侧至今仍较为明显;2)GPS-InSAR高分辨率水平形变场表明,狭义海原断裂左旋滑动速率的递减主要发生在中东段,而中西段递减并不显著,可能与海原断裂向六盘山断裂之间由左旋走滑向逆冲推覆构造转换有关;3)六盘山断裂中—南段的地壳垂直形变和水平形变场特征均显示,该段断裂可能处于强震孕育的中晚期,根据反演得到的断层运动参数和地震地质资料,估算六盘山断裂中—南段发生强震的最大矩震级约达7.5级;4)研究区应变积累较快的区域主要集中在海原断裂附近和海原断裂—香山-天景山断裂之间的左旋剪切区,香山-天景山断裂东南段的应变率场和周围相比明显偏小,存在应变不匹配现象,可能与强震孕育有关。

鄂尔多斯盆地周缘及外围盆地矿权空白区有利拓展方向研究

鄂尔多斯盆地及外围的河套、银川、六盘山、渭河等盆地具有多类型资源同盆共生的特点,在中国陆上大盆地中有明显的资源优势,但资源探明程度低,且存在大量矿权空白区,是油公司选区评价及未来拓展矿权与资源空间的重要目标。通过跟踪勘探新发现,总结地质新认识,类比矿权空白区与其相邻探区成藏条件与资源潜力后发现,鄂尔多斯盆地东缘中段的万镇地区上古生界煤层、暗色泥岩厚度大,生烃强度高,且构造背景稳定,上古生界致密气与深层煤层气具有勘探潜力;盆地北缘杭锦旗、东胜地区石炭系—二叠系煤层残留厚度大,埋深适中,是煤层气与煤化工的有利地区;盆地西缘中—上奥陶统发育广海陆棚相泥页岩,烃源基础好,已发现多个以乌拉力克组(平凉组)为主力烃源岩的台缘礁滩或裂缝型油气藏,结合保存条件研究,认为西缘石沟驿向斜、陶乐断阶带是勘探下古生界碳酸盐岩、海相页岩油气的有利区。外围盆地中以河套盆地临河坳陷最为有利,下白垩统固阳组、渐新统临河组两套优质烃源岩覆盖临河坳陷大部分地区,生烃势能强,围绕主力的生烃凹陷淖西洼槽,东南断阶带发育多组深切的走滑断层,通源性良好,高效成藏模式已经得到证实;六盘山盆地发育与鄂尔多斯盆地相似的三叠系、侏罗系烃源岩,生烃条件好,盆地深层值得进一步探索;银川盆地钻井发现了清水营组咸化湖相烃源岩和含油构造,盆地北部成熟生烃凹陷周缘构造带是有利勘探方向;渭河盆地、河套盆地呼和坳陷处在经济发达区,钻井见到丰富的水溶氦气、地热能、生物气显示,这些地区的油气共伴生资源可作为常规油气的补充进行综合勘探,实现资源就地转化与综合利用。通过研究,建议在鄂尔多斯盆地万镇、合阳、杭锦旗—准格尔旗、陶乐断阶带、石沟驿向斜,以及六盘山盆地海原—固原凹陷、山前推覆构造带,河套盆地临河坳陷东南断阶带、呼和坳陷,银川盆地平罗凹陷等有利区内设置、规划10个新矿权,建议相关单位加强矿权空白区预评价、预研究,积极评价论证新区块油气潜力,为维持油公司矿权进退动态平衡和保障生存空间奠定基础。

六盘山地区大气加权平均温度本地化模型研究

大气中的水汽含量是分析天气发展形势的重要参数,而加权平均温度与水汽含量的计算精度直接相关,想要计算出精准的水汽含量,就要建立本地化的加权平均温度模型.基于六盘山地区微波辐射计和平凉探空站2019-2020年的探测资料,通过数值积分法计算加权平均温度,发现加权平均温度呈现出冬季低、夏季高和受降水影响明显的特征.由于探空站气球的探测高度约为30000 m,而微波辐射计的探测高度固定在10000 m以内,同时受水汽压权重的影响,计算出的加权平均温度的最大值、最小值和平均值分别出现20.0,24.8,23.4 K的差值.通过最小二乘法分别建立基于探空站和微波辐射计资料的加权平均温度模型,并对比实测资料,对两种模型及全球通用的Bevis模型进行精度验证.结果表明,在计算整层大气中的水汽含量时,基于探空站资料的本地化模型的结果更精确;计算10000 m以内水汽含量时,基于微波辐射计资料的本地化模型更加适用.由于自然界绝大部分的降水是由10000 m以内的水汽转化形成,基于微波辐射计的本地化模型对水汽-降水转换效率的研究更有意义.

宁夏六盘山地区马东山组孢粉组合特征及其对恐龙生活古气候的指示意义

宁夏六盘山地区早白垩世马东山组河湖相沉积物表面保存有完整的恐龙足迹化石,赋存其中的孢粉是研究恐龙生活时代古气候信息的良好载体。对六盘山地区隆德县前庄村白垩系马东山组蜥脚类恐龙足迹化石赋存剖面进行了系统的孢粉研究,共鉴定出孢粉类型41属63种。剖面自下而上分为Bisaccates-Jiaohepollis、Classopollis-Jiaohepollis-Cicatricosisporites、Cicatricosisporites-Foraminisporis等3个孢粉组合带。孢粉组合特征反映的地质时代为早白垩世Aptian期-Albian期,恐龙足迹化石的建群植被经历了松柏类向掌鳞杉科,再向蕨类植物的转变,进一步研究认为该地区恐龙生活时代古气候经历了亚热带半湿润气候→亚热带温暖半干旱气候→亚热带湿润气候的变化。这与前人对六盘山地区白垩系马东山组沉积古气候环境的研究结论相一致。

六盘山东麓断裂带土壤气体He浓度的空间分布特征及其与构造活动之间的关系

断裂带土壤气体地球化学特征与区域构造演化密切相关。文中为探讨六盘山东麓断裂带土壤气He浓度的空间分布特征及其与构造活动之间的关系,在六盘山东麓断裂跨断层布设了8条土壤气测量剖面,沿测线开展土壤气He浓度的测量;同时,为进行对比分析,选择位于六盘山东麓断裂以东14km的小关山断裂布设3条跨断层土壤气测量剖面,沿测线开展土壤气He浓度的测量。测量结果显示,六盘山东麓断裂各测量剖面的He浓度平均值为4.983~6.335ppm;小关山断裂各测量剖面的He浓度平均值为4.784~5.235ppm。2条断裂的He浓度在空间分布上均呈现出断裂北部高于断裂中南段的特征,这与断裂的区域活动性差异密切相关。结合前人对六盘山东麓断裂活动时代、闭锁程度、滑移速率、构造应力的研究成果,分析表明六盘山东麓断裂北段的活动性强于断裂中南段。经对比分析认为,六盘山东麓断裂和小关山断裂的构造演化过程相似,且断裂性质均为逆冲型,因此2条断裂土壤气He浓度的空间分布特征一致。

宁夏菌衣属地衣一新记录种——砂地菌衣

通过形态解剖和分子系统学分析,报道宁夏地衣的1个新记录种--砂地菌衣,对其形态特征、生境与分布进行详细描述,并提供形态解剖图.