Bokkos, Nigeria
Bokkos, Nigeria

Plateau State University is a university located in Bokkos, Plateau State Nigeria. It was established in 2005. Wikipedia.

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Yan W.,Plateau State University | Zhong Y.,Northwestern Polytechnical University | Shangguan Z.,Plateau State University
Global Change Biology | Year: 2017

Stomata control the cycling of water and carbon between plants and the atmosphere; however, no consistent conclusions have been drawn regarding the response of stomatal frequency to climate change. Here, we conducted a meta-analysis of 1854 globally obtained data series to determine the response of stomatal frequency to climate change, which including four plant life forms (over 900 species), at altitudes ranging from 0 to 4500 m and over a time span of more than one hundred thousand years. Stomatal frequency decreased with increasing CO2 concentration and increased with elevated temperature and drought stress; it was also dependent on the species and experimental conditions. The response of stomatal frequency to climate change showed a trade-off between stomatal control strategies and environmental factors, such as the CO2 concentration, temperature, and soil water availability. Moreover, threshold effects of elevated CO2 and temperature on stomatal frequency were detected, indicating that the response of stomatal density to increasing CO2 concentration will decrease over the next few years. The results also suggested that the stomatal index may be more reliable than stomatal density for determination of the historic CO2 concentration. Our findings indicate that the contrasting responses of stomata to climate change bring a considerable challenge in predicting future water and carbon cycles. © 2017 John Wiley & Sons Ltd.

Dai J.,Plateau State University | Wang C.,Plateau State University | Polat A.,University of Windsor | Santosh M.,Kochi University | And 3 more authors.
Lithos | Year: 2013

The Cretaceous Xigaze ophiolite is best exposed at the central Yarlung Zangbo Suture Zone (YZSZ, Tibet) which also includes the Gangdese arc and the Xigaze forearc basin. This study reports new geochronological and geochemical data for this ophiolite to revisit its geodynamic and petrogenetic evolution. The Xigaze peridotites have low CaO and Al2O3 contents and U-shaped Rare Earth Element (REE) patterns, suggesting that they are residues after moderate to high degrees of partial melting and were modified by infiltration of Light Rare Earth Element (LREE)-enriched boninitic melts. The Xigaze crustal rocks belong to two groups: Mid-Ocean Ridge Basalt (MORB)-like rocks and boninitic rocks showing a uniform LREE depletion and flat to LREE enrichment on chondrite-normalized patterns, respectively. Geochemically, both groups show the influence of subducting oceanic slab-derived fluids. LA-ICPMS zircon U-Pb and Lu-Hf analyses from dolerite and quartz diorite dikes, which intruded into the mantle peridotite, and dolerite sheeted sills show that they were generated between 127 and 124Ma. The zircons possess positive εHf(t) values ranging from +7.5 to +17.3. Taking into account the geological and geochronological characteristics of the central-western YZSZ, we propose that ophiolites in this region formed in a forearc spreading setting through rapid slab rollback during subduction initiation between 130 and 120Ma. Following this stage of spreading, the forearc was stabilized and the zone of melting migrated beneath the Gangdese arc producing the voluminous Late Cretaceous granitoids displaying depleted mantle-type Hf isotopic compositions. Our model provides a new explanation for the generation and evolution of forearc-type ophiolites. © 2013 Elsevier B.V.

Zhang S.,Plateau State University | Shao M.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research
Hydrological Processes | Year: 2017

Temporal stability of soil moisture has been widely used in hydrological monitoring since it emerged. However, the spatial analysis of temporal stability at the landscape scale is often limited because of insufficient sampling numbers. This work made an effort to investigate the spatial variations of temporal stability of soil moisture in an oasis landscape. The specific objectives of the study were to explore the spatial patterns of temporal stability and to determine the controlling factors of temporal stability in the desert oasis. A time series of soil moisture measurements were gathered on 23 occasions at 118 locations over 3 years in a rectangular transect of approximately 100 km2. The nonparametric Spearman's rank correlation coefficient, standard deviation of relative difference (SDRD), and mean absolute bias error (MABE) were used to quantify the temporal stability of soil moisture. Results showed that the temporal stability of soil moisture was depth dependent and season dependent. The spatial pattern of soil moisture in a deep soil layer and between two same seasons generally had a high temporal stability. SDRD and MABE were spatially autocorrelated and exhibited strong spatial structures in the geographic space. The concept of temporal stability can be extended to describe the time-stable areas of soil moisture with geostatistics. There were great differences between SDRD and MABE in describing the temporal stability of soil moisture and in identifying the controlling factors of temporal stability. In this case, MABE was a better alternative to estimate the areal mean soil moisture using representative locations than SDRD. Land use type, soil moisture condition, and soil particle composition were the dominant controls of temporal stability in the oasis. These insights could help to better understand the essence of temporal stability of soil moisture in arid regions. © 2017 John Wiley & Sons, Ltd.

Wang C.,Plateau State University | Dai J.,Plateau State University | Zhao X.,Tongji University | Zhao X.,University of California at Santa Cruz | And 5 more authors.
Tectonophysics | Year: 2014

The surface uplift history of the Tibetan Plateau (TP) offers a key testing ground for evaluating models of collisional tectonics and holds important implications for processes ranging from global cooling to the onset of the Asian monsoon. Various models have been proposed to reveal the surface uplift history of the TP, but controversies remain. We evaluate these models using data from sedimentology and stratigraphy, structural geology, magmatism, exhumation, and paleoaltimetry studies. Structural analyses indicate that thrust belts, which spread from the central TP outward toward its surrounding margins, accommodated most of the India-Asia convergence, and facilitated crustal shortening and thickening in the central TP. Eocene adakitic rocks located in the Qiangtang and the Lhasa blocks likely were generated by partial melting of an eclogitic source. Paleogene (50-30. Ma) potassic rocks only occur in the Qiangtang block, whereas Late Oligocene-Late Miocene (26-8. Ma) potassic rocks occur both in the Qiangtang and Lhasa blocks. Low-temperature thermochronologic ages in the central TP are older than 40-35. Ma, whereas those in the margins are younger than 20. Ma (mostly Late Miocene, and Pliocene/Pleistocene in age). Independent paleoaltimetry estimates suggest that the Lhasa and Qiangtang terranes attained their current elevations during the Eocene, most likely due to the initial collision between India and Lhasa, whereas the Hoh Xil basin area to the north and Himalayas to the south were still low, even below sea level in the latter case. We argue for an inside-out growth pattern for the Tibetan Plateau. The TP grew southward and northward from a nucleus of high topography and is likely to continue expanding along the Mazar Tagh fault to the northwest, the Kuantai Shan-Hei Shan-Longshou Shan to the northeast, the Longquan Shan to the east and the Shillong plateau to the south if the northward force of India would not diminished. © 2014 Elsevier B.V.

Li Y.,Plateau State University | Wang C.,Plateau State University | Zhao X.,University of California at Santa Cruz | Yin A.,University of California at Los Angeles | Ma C.,Plateau State University
Gondwana Research | Year: 2012

New field mapping reveals a large Cenozoic thrust system in the Tanggula Range and Tuotuohe region, central Tibet. The thrust system is parallel to the Tanggula Range, and it is termed the Tanggula thrust system (TTS). Three thrust belts can be identified in this thrust system. From south to north, they are the Geraddong-Esuima thrust belt (GEB), the Quemocuo-Gaina fold-thrust belt (QGB), and the Baqing-Wulwl thrust belt (BWLB). The deformation styles can be classified as high-angle imbricate thrust, fold thrust and lower-angle imbricate thrust, respectively. The initiation of sedimentation in the Tuotuohe Basin and stratigraphic unconformities indicate that the thrust system was developed during 52-23. Ma. Sequential filling patterns, sedimentary facies and paleocurrents indicate that the Tuotuohe Basin was a foreland basin in front of the TTS. Restored structural sections suggest 89. km (60%) of N-S shortening in the TTS and 96. km (48%) shortening in the Tuotuohe Basin. The thrust system has not only influenced the development of this Cenozoic basin, but also resulted in the rapid uplift of the Tanggula Range during the Eocene and Oligocene. © 2012 International Association for Gondwana Research.

Dai J.,Plateau State University | Zhao X.,University of California at Santa Cruz | Wang C.,Plateau State University | Zhu L.,Chengdu University of Technology | And 2 more authors.
Gondwana Research | Year: 2012

The surface uplift of the Tibetan Plateau is the key boundary condition in many Cenozoic geological events ranging from global cooling to changes of Asian environments during Cenozoic. However, poorly constrained timing for the uplift of Tibetan Plateau makes these interpretations highly debatable. Here we report results from sedimentology, detrital zircon U-Pb and Lu-Hf isotopic compositions, and paleomagnetic signatures from both the eastern and western Hoh Xil basins of north-central Tibetan Plateau. Sedimentary lithofacies and facies associations analyzed in the western Hoh Xil basin indicate they were deposited in a braided fluvial system and alluvial fan, similar with the Fenghuoshan Group, eastern Hoh Xil basin. Provenance analyses from conglomerate clast compositions, paleocurrent orientations, and detrital zircon U-Pb and Lu-Hf isotopic compositions document sediments in both western and eastern basins were derived from the Qiangtang and Lhasa blocks. These observations, in combination with comparative paleomagnetic results, imply that Hoh Xil basin was a single, wide basin during Paleogene. The period of Hoh Xil basin deposition was coeval with significant period of the early Cenozoic uplift and erosion of the Qiangtang and Lhasa blocks. These observations not only reinforce the suggestion that the Qiangtang and Lhasa blocks were uplifted during Eocene to form a proto-Tibetan Plateau, but also imply that the proto-Tibet Plateau is vast in areal extent. The large dimension and high elevation of the proto-Tibetan Plateau probably contributed to the global cooling during the early Eocene. © 2011 International Association for Gondwana Research.

Mills M.S.L.,Plateau State University | Mills M.S.L.,University of Cape Town
Biodiversity and Conservation | Year: 2010

Despite Angola's central scarp forests being recognised as a critical global priority for bird conservation, fine-scale information on threatened bird distributions and patterns of bird diversity are lacking. These data are essential to identify sites within the Western Angola Endemic Bird Area that should be targeted for conservation. First endemic and near-endemic species and subspecies, and species with isolated populations along the Angolan scarp were identified to highlight taxa of greatest priority for conservation and for use in studying the evolutionary origins of the region. Thereafter survey data collected during 2005 from 13 forest sites along the central scarp was analysed. These data show that there are three distinct bird communities across the width of the escarpment, each associated with a distinctive forest type. Of note is the finding that threatened and Near Threatened endemic species occur almost exclusively in the dry forests adjacent to the main escarpment, rather than in the moistest forests found on the main escarpment, which instead are richer in Congo Basin forest birds. Based on these data, summaries of ranges, populations and conservation threats are given for the seven most threatened bird species. Attention is drawn to threats to the habitats of greatest importance to these species. A conservation area network should be established that encompasses the full spectrum of bird diversity described, to ensure survival of current unique taxa and the future evolutionary potential of the area. © 2010 Springer Science+Business Media B.V.

Dai J.,Plateau State University | Wang C.,Plateau State University | Hourigan J.,University of California at Santa Cruz | Li Z.,Chengdu University of Technology | Zhuang G.,Yale University
Journal of Geology | Year: 2013

To test previously suggested exhumation histories of the Gangdese Batholith in the central part of the Transhimalayan plutonic belt, we conducted paired apatite and zircon (U-Th)/He thermochronological investigations of the Yarlung Zangbo gorge in the central part of the batholith. Age-elevation relationships and multisystem thermochronometers showed three periods of accelerated exhumation (~46-48, ~22-18, and ~11-8 Ma). Combining these data with previously published thermochronological ages and synthesizing these ages with regional geological events provides an entire exhumation history. The Cretaceous-Early Paleogene exhumation of the Gangdese Batholith was probably caused by both the northward subduction of the Neo-Tethys and the collision between the Lhasa and Qiangtang blocks. The Early Miocene rapid exhumation might be a response to shortening caused by the Gangdese Thrust or erosion driven by dynamic uplift following lithospheric delamination. In contrast, the Late Miocene exhumation is coincident with both the proposed capture of the Yarlung Zangbo gorge by a foreland draining catchment and the intensification of the Asian monsoon, as well as normal faulting. Hence, the latest stage of exhumation might be attributed to the incision of the Yarlung Zangbo gorge, the activity of a north-south fault, or both. © 2013 by The University of Chicago. All rights reserved.

Dai J.,Plateau State University | Wang C.,Plateau State University | Hourigan J.,University of California at Santa Cruz | Santosh M.,Kochi University | Santosh M.,China University of Geosciences
Tectonophysics | Year: 2013

To understand the magmatic and tectonic events in the Eastern Kunlun Range, we conducted systematic zircon U-Pb geochronology, and paired zircon (ZHe) and apatite (AHe) (U-Th)/He themchronology investigations in the central and eastern segments of this range. Zircon U-Pb ages show two-stage magmatic events of Late Silurian and latest Permian-Early Jurassic. ZHe and AHe ages and multi-system thermochronometers reveal multi-stage rapid cooling events. From a combination of these data with previously published geochronological and thermochronological ages, and regional geological setting, we confirm several important Phanerozoic tectono-magmatic events in this region. Whereas the Silurian granites might be related to a small paleo-ocean subduction and subsequent collision, the latest Permian-Early Triassic granitoids were produced by northward subduction of the Songpan-Ganzi Paleo-Tethyan ocean. The Late Triassic-earliest Jurassic granitoids and Late Triassic-Early Jurassic exhumation are interpreted as response to the collision between Kunlun-Qaidam and Qiangtang. Samples close to the Kunlun Fault show rapid Late Oligocene-Early Miocene exhumation (1.3-1.6 km/Ma), whereas those from the northern part of central segment display extremely low exhumation rates (0.02-0.05 km/Ma). This heterogeneous denudation during 30-20. Ma between northern and southern part of the central segment requires that crustal thickening was completed by lower-crustal underthrusting with little exhumation or crustal thickening in pre-Cenozoic times. The activity of the Kunlun Fault and associated normal faulting component were probably responsible for this stage of rapid exhumation in the southern part. The complex tectono-magmatic evolution of the Eastern Kunlun Range is controlled by pre-Cenozoic paleo-ocean subductions and subsequent continent collisions and Paleogene India-Asia collision. © 2013 Elsevier B.V.

Dai J.-G.,Plateau State University | Wang C.-S.,Plateau State University | Hebert R.,Laval University | Santosh M.,Kochi University | And 2 more authors.
Chemical Geology | Year: 2011

The Zhongba ophiolite is located in the western part of the Yarlung Zangbo Suture Zone (YZSZ) separating Eurasia to the north from the Indian plate to the south. This ophiolite comprises a well-preserved mantle sequence dominated by harzburgites with minor dunites. Highly depleted modal, mineral and bulk rock compositions of the harzburgites indicate that they are residues after moderate to high degrees of partial melting (13-24%) mainly in the spinel-stability field. These rocks display typical U-shaped chondrite-normalized Rare Earth Element (REE) patterns and fractionated chondrite-normalized Platinum Group Element (PGE) patterns. These characteristics, in combination with their hybrid mineral and whole-rock compositions intermediate between those of abyssal and forearc peridotites, indicate melt-rock interaction resulting in the selective enrichment of LREE and Pd. We propose a two-stage model to explain the generation of the Zhongba harzburgites: 1) original generation from a MORB-source upper mantle, and 2) subsequent trapping as part of a mantle wedge above a subduction zone. Comparable observations from the ophiolitic massifs along the whole YZSZ allow us to propose that a ca. 2500-km long complex subduction system was active between India and the Lhasa terrane, Burma, and the Karakoram microcontinent within the Neo-Tethys during the Early Cretaceous, similar to the modern active intra-oceanic subduction systems in the Western Pacific. © 2011 Elsevier B.V.

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