Sequence of the Cenozoic Mammalian Faunas of the Linxia Basin in Gansu, China

In the Linxia Basin on the northeast margin of the Tibetan Plateau, the Cenozoic strata are very thick and well exposed. Abundant mammalian fossils are discovered in the deposits from the Late Oligocene to the Early Pleistocene. The Dzungariotherium fauna comes from the sandstones of the Jiaozigou Formation, including many representative Late Oligocene taxa. The Platybelodon fauna comes from the sandstones of the Dongxiang Formation and the conglomerates of the Laogou Formation, and its fossils are typical Middle Miocene forms, such as Hemicyon, Amphicyon, Platybelodon, Choerolophodon, Anchitherium, and Hispanotherium. The Hipparion fauna comes from the red clay of the Liushu and Hewangjia Formations, and its fossils can be distinctly divided into four levels, including three Late Miocene levels and one Early Pliocene level. In the Linxia Basin, the Hipparion fauna has the richest mammalian fossils. The Equus fauna comes from the Wucheng Loess, and it is slightly older than that of the classical Early Pleistocene Nihewan Fauna. The mammalian faunas from the Linxia Basin provide the reliable evidence to divide the Cenozoic strata of this basin and correlate them with European mammalian sequence.

Terrestrial Mio-Pliocene Boundary in the Linxia Basin,Gansu,China

The Lower Pliocene of the Linxia Basin in Gansu Province is one of only a few representative sections for the Early Pliocene sedimentary records in northern China, and even in East Asia. Recently,abundant mammalian fossils were found from the base of red clays of the Lower Pliocene Hewangjia Formation at Duikang in Guanghe County within this basin. Previously, the Pliocene mammals were sparsely found in China, and most were collected from fluvial and lacustrine deposits in the eastern Loess Plateau. Mammals from the widely distributed Pliocene Hipparion Red Clay are less in number.The known fossils from Duikang include 20 species and belong to the Shilidun Fauna. Their faunal components are similar to the Early Pliocene Gaozhuang Fauna from Ynshe, Shanxi. On the other hand, some taxa from Duikang have not been found in the Gaozhuang Fauna, are slightly more primitive in evolutionary level, and appeared mainly in the Late Miocene. As a result, the age of the Duikang fossils may be slightly earlier than that of the Gaozhuang Fauna and closer to the lower boundary of the Piiocene. The Duikang fossiliferons bed is 0.8 m above the top of the Late Miocene Linshu Formation, and the first occurrence of the three-toed horse Hipparion pater can be regarded as a biostratigraphical marker of the Miocene/Pliocene boundary. In conclusion, Duikang is an ideal candidate locality to establish as the stratotype of the lower boundary of the Chinese terrestrial Pliocene.

Fossil Equidae in the Linxia Basin with Biostratigraphic and Paleozoogeographic Significance

The Linxia Basin is characterized by an abundance of Cenozoic sediments,that contain exceptionally rich fossil resources.Equids are abundant in the Linxia Basin,the fossil record of equids in this region including 16 species that represent 10 genera.In comparison to other classic late Cenozoic areas in China,the Linxia Basin stands out,because the fauna and chronological data accompanying Linxia equids render them remarkably useful for biostratigraphy.The anchitheriines in the region,such as Anchitherium and Sinohippus,represent early equids that appeared in the late stages of the middle and late Miocene,respectively.Among the equines,most species of Chinese hipparions have been identified in the Linxia Basin and some species of the genera Hipparion and Hippotherium have FAD records for China.Furthermore,Equus eisenmannae is one of the earliest known species of Equus in the Old World and is well-represented at the Longdan locality.Some species with precise geohistorical distributions can serve as standards for high-resolution chronological units within this framework.Located at the eastern margin of the Tibetan Plateau and subject to considerable uplift,the Linxia Basin has served as a biogeographic transition area for equids throughout the late Cenozoic.

Evaluation of Water Resources Carrying Capacity in Gansu Section of Yellow River Basin Based on Fuzzy Comprehensive Evaluation Model

As a basic natural resource and strategic economic resource,the development and utilization of water resources is an important issue related to the national economy and people's livelihood.How to scientifically evaluate the water resources carrying capacity is the premise to improve the regional water resources carrying capacity and ensure the regional water security.The Gansu section of the Yellow River basin is an important water conservation and recharge area.Whether the water resources in this area can ensure the normal operation of the ecosystem and whether it can carry the sustainable development of social economy is the key to realize the high-quality development of the Yellow River basin.In this study,from the three dimensions of water consumption per capita,water consumption of 10000 yuan GDP and ecological water use rate,by constructing the evaluation index system and index grading standard of water resources carrying capacity,the fuzzy comprehensive evaluation model was used to evaluate the water resources carrying capacity of Gansu section of the Yellow River Basin,in order to provide theoretical decision-making basis for the comprehensive development,utilization and planning management of water resources in Gansu section of the Yellow River basin and even the whole basin,and help the high-quality development of the Yellow River basin.

Relations Between Paleoclimatological Conditions and Mineralogical Characteristics of Clays in Miocene Sediments at Linxia Basin, China

Linxia Basin is a late Cenozoic fault-block basin along the border between the Tibet plateau and the Loess plateau in Northwestern China. Its formation and sediments record may be directly affected by the structural dynamics and the uplift of the Tibet Plateau. For this reason, we studied the mineral characteristics of the Maogou formation of Miocene sediments using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD results showed that quartz, chlorite, illite, calcite, plagioclase, orthoclase, kaolinite, and trace palygorskite are present throughout the sequence of the cross-section in Linxia basin. In contrast, gypsum and ankerite occur occasionally in the upper portion of the Miocene deposits. The content of calcite varied with layers in the profile and was relatively concentrated in mudstone. Chlorite and illite were observed transforming into palygorskite under SEM observation. Based on the mineral characteristics and the change of mineral composition, especially the clay minerals, it could be inferred that an arid environment prevailed in the region with warm and cold intervals during Miocene time.

On a New Genus of Basal Neoceratopsian Dinosaur from the Early Cretaceous of Gansu Province, China

A new genus and species of basal neoceratopsian dinosaur, Auroraceratops rugosus, is reported based on material from the Early Cretaceous Xinminpu Group in the Gongpoquan Basin of Gansu Province, China. Auroraceratops is represented by a nearly complete skull and low jaws, and different greatly from all other neoceratopsians by its considerable breadth of the nasals, fungi form expansion of the dorsal end of the lacrimal, highly developed rugosity of the jugal, dentary and surangular, and inflated, striated premaxillary teeth. The finding of Auroraceratops adds diversity and helps elucidate the evolution of basal neoceratopsian dinosaurs.

Palynology of Yanchang Formation of Middle and Late Triassic in Eastern Gansu Province and Its Paleoclimatic Significance

Xifeng （西峰） oilfield was recently found in the southwest of the Ordos basin. The oil source rocks are the Chang 7 Section of Yanchang （延长） Formation. In order to study the paleoclimate that controlled the formation of source rocks, a systemically palynological research on related beds in Yanchang Formation has been carried out. The core samples were analyzed with classical palynological techniques and the organic-walled sporomorphs from these samples were observed, identified and photographed under a light microscopy and a fluorescence microscopy. Abundant sporopollen were found in drilling cores from Chang 8 and Chang 7 sections, and two assemblages were distinguished： the Aratisporites-Punctatisporites assemblage and the Asseretospora-Walchiites assemblage. Their characteristics are similar to those of the assemblage of Tongchuan （铜川 ） Formation and the assemblage of Yanchang Formation in southeast Ordos basin, respectively. Their geological times are Ladinian of late Middle Triassic and Carnian of early Late Triassic, respectively. The correlation of palynoflora with their parent plants suggests the paleoclimate of eastern Gansu （甘肃） Province in the Middle and Late Triassic was warm and rainy with prosperous vegetation. The palynoflora indicated the area was in a temperate to subtropical zone then. Both the ecological types and differentiation degree curves of sporopollen indicated the period during Chang 8 and Chang 7 sections was warm and wet, and the phase accorded with large-scale lake transgression in Chang 8 Section and the largest lake area in Chang 7 Section. North China in Middle and Late Triassic was located in a warm and rainy, temperate and subtropi- cal zone. The palynofloras in Chang 8 and Chang 7 sections have the characteristics of North China flora, however they also indicate wetter and warmer climate due to their proximity to the large lakes. The period of Chang 8 to Chang 7 sections is the climax of the expansion of the lake, and the bloom of fresh algae during the period, which helped form the high-quality source rocks in Chang 7 Section.

A new type of dinosaur eggs from Early Cretaceous of Gansu Province, China

甘肃省早白垩世地层中,出土了大量恐龙骨骼以及恐龙足迹化石,但是至今未有蛋化石的报道。根据发现于兰州-民和盆地下白垩统河口组的蛋壳化石,建立一恐龙蛋新蛋属、蛋种,并将其归于一新蛋科:Polyclonoolithidae(多小枝蛋科)。新发现的蛋化石标本不同于所有已知的恐龙蛋类型,具有独特的显微特征组合:分叉的蛋壳单元向外延伸至蛋壳外表面,并未在靠近蛋壳外表面处融合成层;弦切面上具相互链接或独立的多角形的蛋壳单元;以及不规则的气孔道。中国的恐龙蛋化石大多出自晚白垩世地层,仅在辽宁有早白垩世恐龙蛋的报道。新发现扩展了中国恐龙蛋化石的地质和地理分布,也有可能为圆形蛋科蛋壳结构的起源提供新的认识。

Late Cenozoic deformation subsequence in northeastern margin of Tibet --Detrital AFT records from Linxia Basin

Two events of Tibet uplifting are revealed by detrital apatite fission track (AFT) age data from Linxia Basin. They occurred at about 14 and 5.4-8.0 MaBP respectively. We interpret the first one to be related to the uplifting of the northern Tibet, which might have resulted from convectively removing the thickened lower lithosphere. The second one is a result of Laji Mountain uplifting. Numerous studies of the Tibetan Plateau suggest that the onset time of the deformation in the northeastern margin of Tibetan Plateau and the time of Tibet attaining to its present elevation is about 8 MaBP. They are approximately coincident with the uplift of Lajishan Mountain. It suggests that the northeastern margin of Tibet propagated northeastwardly to its present site in about 8 MaBP for accommodating the sustained convergence between India-Eurasia plate and for keeping its high elevation. The active block pattern dominating the strong earthquake distribution of Chinese continent probably formed at about 8.0-5.4 MaBP.

Discovery of Giraffokeryx in China and the Tertiary Chronostratigraphy of Linxia, Gansu Province

The Linxia Basin in Gansu Province, extending across areas of Linxia and Lintao, istopographically located in the northeastern edge of the Qinghai-Tibet Plateau. There arewell-developed Tertiary red deposits with a total thickness of about 500 m in this basin, whichwas named the Gansu Group by Hu Min in 1946, representing the Tertiary sediments.

甘肃黄河流域土壤保持服务数据集(2001-2015年)

甘肃黄河流域是一个生态问题和发展问题交织在一起的自然-社会-经济复合生态系统,其生态系统土壤保持服务是防止水土流失和推动高质量发展的重要保障。使用归一化植被指数、土地利用产品MCD12Q1、降水数据、数字高程模型数据和土壤数据库HWSD v1.1,运用修正通用土壤流失方程RUSLE,计算得到了甘肃黄河流域的土壤保持服务年度数据集。该数据集,空间范围为33°6′29″N-40°0′6″N、97°23′38″E-108°42′38″E,时间跨度为2001-2015年,可为制定土壤保持服务措施提供科学依据,也为评估生态安全和构建生态安全格局提供重要数据支撑。实体数据集获取网址为http://www.ncdc.ac.cn/portal/metadata/a918f7ed-5988-44ea-80ad-ee14acab89aa.

基于LightGBM模型的甘肃省临夏县滑坡易发性评价

甘肃省临夏县地质环境复杂,滑坡灾害发育,对当地居民生产生活造成严重威胁,亦对工程建设的开展造成一定阻碍,因此,选取高效准确的机器学习方法对临夏县进行滑坡易发性评价具有重大意义。首先依据遥感影像和野外勘察资料,选取了1718处滑坡样本,遴选了滑坡灾变的16种影响因子并建立滑坡影响因子评价体系;再结合预测精度和运行时间等指标对比了轻量级梯度提升机(LightGBM)模型与主流机器学习模型的性能;最后利用混淆矩阵分级方法进行了基于LightGBM模型的临夏县滑坡易发性评价。结果表明:临夏县重要滑坡影响因子为地表植被和地形地貌因子,其中土地覆盖为最主要影响因子;LightGBM模型预测精度高达0.931,且运行速度仅为11.7 s,既能保证高精度又极大提升了运行效率;在抽稀后的数据集上,LightGBM模型的预测表现、校准程度和分级结果均优于随机森林(RF)模型;混淆矩阵分级法的较高和高易发区内滑坡分布更为集中,在14.94%的区域内分布着86.86%的滑坡灾害点。滑坡易发性评价结果较好地反映了研究区内滑坡分布发育情况,可为当地工程建设及防灾减灾工作提供一定指导。

临夏盆地中新世一可能的新犬熊

报道了甘肃临夏盆地具体产地未知的一件犬熊下颌。该下颌展现出进步的牙齿特征,与过去发现于欧洲以及南亚的马德里犬熊Magericyon近似。这件犬熊化石指示东亚的犬熊多样性比以往认知的更高,但还需要更多具有明确层位信息的犬熊化石来进一步揭示东亚犬熊的演化。

黄河流域甘肃段生态敏感性评价研究——以广河县为例

为探究适用于黄河流域甘肃段生态环境的保护理论与方法,解决该区域生态环境保护与社会经济发展的矛盾问题,选取适合黄河流域甘肃段生态敏感性评价因子,利用层次分析法和GIS空间分析方法,定量评价广河县生态敏感性,并选取GDP、人均GDP、人口密度等6项社会经济指标,结合耦合度模型和耦合协调度模型,分别探究生态敏感性与其的耦合协调关系。研究表明:(1)水体、土壤可蚀性、植被覆盖与土地利用类型对广河县生态敏感性影响较强烈。(2)生态敏感性子系统与各社会经济指标子系统呈现出较强的空间相关性,互相依存关系明显,耦合度水平均处于较高状态。(3)耦合协调度研究中生态敏感性子系统与人均GDP、矿产资源指标子系统处于协调发展状态,生态敏感性子系统与GDP、人口密度、工业指标与养殖业指标子系统处于拮抗发展状态。研究生态敏感性与社会经济发展的相关性,为该区域提供差异化的发展与保护协调路径,并为同类型区域提供借鉴。

基于熵权TOPSIS的黄河流域甘肃段水资源承载力评价

为评价黄河流域甘肃段水资源承载力,以黄河流域甘肃段4个二级分区为研究对象,初选20个评价指标,利用信息敏感性和相关性分析法剔除敏感性较低和相关性较高的7个指标,最终确定13个评价指标。从系统角度将指标分为水资源、社会、经济、生态环境4个子系统,利用熵权法与TOPSIS模型结合的方法计算综合得分,并利用障碍因子诊断模型分析4个二级分区的水资源承载力障碍因子。结果表明:空间维度上,黄河流域甘肃段水资源承载力存在空间差异性,龙羊峡以上分区水资源承载力最高,龙羊峡—兰州分区与兰州—河口镇分区水资源承载力次之,龙门—三门峡分区水资源承载力最低;时间维度上,除龙羊峡以上分区外其余3个二级分区水资源承载力均有缓慢上升趋势;人均水资源量、产水模数、人均供水量、人口密度、城镇化率及生态环境用水率是影响黄河流域甘肃段水资源承载力的主要障碍因子,建议优化水资源配置、调整用水结构、促使经济发展与水资源承载力相匹配等,以提升及保持黄河流域甘肃段水资源承载力。

渭河流域甘肃段生态脆弱性时空演变分析

为及时了解渭河流域生态环境状况并客观掌握其时空变化特征,本研究以渭河流域甘肃段为研究区域,选取生态敏感性-生态适应性-生态暴露度(VSD)概念模型,构建渭河流域甘肃段生态脆弱性评价指标体系,以栅格为基础评价单元,结合空间主成分分析和地理探测器等方法对2005~2020年渭河流域甘肃段生态脆弱性进行评价。结果表明:(1)渭河流域甘肃段生态脆弱性以中度脆弱性为主,脆弱性程度由东南地区向西北地区逐渐增加;(2) 2005~2020年生态脆弱性综合指数分别为2.83、2.75、2.62、2.51,呈逐渐减小的趋势;(3)微度脆弱区以林地为主,轻度脆弱区以林地、草地和耕地为主,中度脆弱区和重度脆弱区以耕地和草地为主,极度脆弱区逐渐转为以城市居民点和工矿用地、未利用地为主。总体上,2005~2020年渭河流域甘肃段生态脆弱程度有所下降,生态环境质量朝好转趋势发展。

黄河流域甘肃段生态福利绩效评价及影响因素

文章基于超效率SBM模型、面板Tobit模型等方法,对黄河流域甘肃段的生态福利绩效进行测度,并分析其影响因素。研究结果表明:2010—2020年,黄河流域甘肃段生态福利绩效呈逐年上升趋势,地区间差异变大;除天水市外,全要素生产率水平均超过1,并随时间呈“M”型波动,其中低技术效率制约着天水市全要素生产率提升;人口密度、城镇化水平和年平均温度是影响黄河流域甘肃段生态福利绩效提升的主要因素,其中城镇化水平、年平均气温起正向作用,而人口密度则起负向影响,其他因素如降水量、教育支出、公路里程数等影响不显著。

黄河流域甘肃段城镇经济空间结构特征演变及动因探析

[目的]在黄河流域生态保护和高质量发展成为重大国家战略、黄河流域甘肃段作为甘肃省国土空间格局优化主体的时代背景下,从经济视角探索区域城镇空间结构的内在属性以提高黄河流域甘肃段总体发展水平。[方法]借助引力模型、区位商指数及地理探测器分别从城镇经济联系网络结构、城镇竞争优势结构、产业集聚结构3个方面对黄河流域甘肃段城镇经济空间结构的演变特征、动因进行探讨。[结果]区域经济联系网络水平和城镇竞争优势水平均逐步提升,其结构由单中心簇型向多中心簇型演进,第一产业集聚结构经历了“全局型结构—穿孔型结构”演变过程,第二产业集聚结构为穿孔型结构,且该结构逐步增强,第三产业集聚结构经历了“穿孔型结构—局部型结构—穿孔型结构”的演变过程;黄河流域甘肃段城镇竞争优势与地方政府财政收入关系密切,相应产业产值占比越高产业发展越集聚,此外受生态保护、供给侧结构性改革的影响,已经开始走去工业化及工业转型道路,固定资产投资和政府财政支出在发展第二产业上的投入占比将下降。

黄河流域上游生态环境-经济发展-城镇化耦合协调发展--以甘肃段为例

以黄河流域甘肃段为例,运用耦合协调发展模型、ArcGIS软件、灰色关联度模型对2010—2020年生态环境、经济发展、城镇化三者耦合协调发展的时空格局及其驱动因素进行研究.结果表明,黄河流域甘肃段生态环境-经济发展-城镇化系统评价值总体呈上升趋势,城镇化和生态环境系统评价值呈持续上升特征,经济发展系统评价值出现波动下降趋势;黄河流域甘肃段各市(州)耦合度呈上升态势并达到较高水平,协调度总体不高,初级协调是主要类型,各市(州)协调度在空间上呈现出“西高东低”的分布态势;生态环境、经济发展、城镇化耦合协调发展的驱动因素影响力从强到弱依次为政府能力、经济发展水平、水资源、产业结构、科技投入、对外开放程度.

黄河流域自然保护地空间格局演变与影响因素研究——以青甘宁片区为例

自然保护地空间格局及影响因素的研究对于构建黄河流域以国家公园为主体的自然保护地体系具有现实意义。以黄河流域青甘宁片区国家级自然保护地为案例地,基于2003-2021年306个自然保护地点数据,借助ArcGIS 10.8空间分析工具,运用核密度分析、标准差椭圆等方法,从类型、密度等方面,对研究区域内自然保护地空间分布的时空格局进行研究;运用空间分析、相关性分析和地理探测器对影响因素进行探讨。结果表明,1)青甘宁黄河流域自然保护地空间结构类型为凝聚型和随机型;2)从分布密度上看,呈现出以省会及重点城市为核心,以黄河为轴的点状集聚与线状扩张并存的演变态势;3)自然保护地空间格局方向分布变化不显著,方向与黄河在该区域的流向一致;4)影响流域自然保护地空间分布的因素依次为社会因素(0.6260)>自然因素(0.5797)>经济因素(0.5413),影响因素存在双因子增强和非线性增强。社会因素成为首要因素与青甘宁地区的自然人文环境密切相关,影响因素在共同作用下最终形成了自然保护地空间格局。