The early-Eocene climate optimum (EECO) event in the Qaidam basin, northwest China: clay evidence

Clay Minerals ◽  
2011 ◽  
Vol 46 (4) ◽  
pp. 649-661 ◽  
Author(s):  
C. W. Wang ◽  
H. L. Hong ◽  
B. W. Song ◽  
K. Yin ◽  
Z. H. Li ◽  
...  
Keyword(s):  
Transition Period ◽  
Qaidam Basin ◽  
Global Climate ◽  
Clay Mineralogy ◽  
Northwest China ◽  
Early Eocene ◽  
Humid Climate ◽  
Seasonally Dry ◽  
Mineralogical Study ◽  
Climate Evolution

AbstractClay mineralogy and its palaeoclimatic interpretation of the early-Eocene (∼53.3–49.70 Ma) sediments at Lulehe, Qaidam basin, northwest China, were investigated using optical microscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD). The interval of ∼53.3–49.70 Ma, including the early-Eocene climate optimum (EECO) with isotopic events, was the transition period of “greenhouse” to “icehouse”. Climate changes during the episode were documented in the sediments and were expressed by the proportion of clay species and clay indices, as well as by the proportion of non-clay minerals, gypsum, halite and calcite. Our results suggest that a warm and humid climate prevailed over the period ∼53.3–52.90 Ma, followed by a warm and seasonally dry and humid climate in the period ∼52.90–51.0 Ma and a subsequently warm and humid climate in the period ∼51.0–49.70 Ma. Three warmer and more humid intervals were observed at 52.7, 51.0 and 50.5 Ma based on clay indices. The climate evolution in the Qaidam Basin during the period derived from the clay mineralogical study is in good agreement with the early Eocene global climate change, and the warm and seasonally dry and humid episode in the early Eocene in Qaidam basin is a regional response to the global early-Eocene climate optimum.

scholarly journals Clay Minerals and Element Geochemistry of Clastic Reservoirs in the Xiaganchaigou Formation of the Lenghuqi Area, Northern Qaidam Basin, China

Minerals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 678 ◽  
Author(s):  
Sun ◽  
Wang ◽  
Guo ◽  
Wang ◽  
Jiang ◽  
...  
Keyword(s):  
Clay Minerals ◽  
Chemical Weathering ◽  
Qaidam Basin ◽  
Global Climate ◽  
Sedimentary Environment ◽  
Clay Mineralogy ◽  
Late Eocene ◽  
Element Geochemistry ◽  
Humid Climate ◽  
Climate Conditions

We performed mineralogical and geochemical analyses of core samples from the Lenghuqi area in the northern marginal tectonic belt of the Qaidam Basin. The clay mineralogy of the Xiaganchaigou Formation sandstone is dominated by I + I/S + C types and characterized by high illite, a higher mixed-layer illite/smectite and chlorite, lesser smectite, and an absence of kaolinite. The clay minerals reflect that the Oligocene sedimentary basin formed in an arid-semi-arid climate with weak leaching and chemical weathering, and that diagenesis occurred in a K+- and Mg2+-rich alkaline environment. Measured major oxide concentrations show clear correlations. The lower Xiaganchaigou Formation is representative of a dry and cold freshwater sedimentary environment, whereas the upper Xiaganchaigou Formation is warmer and more humid. Trace element and rare earth element variations indicate that the paleoclimate conditions of the lower Xiaganchaigou Formation sedimentary period were relatively cold and dry, while the upper Xiaganchaigou Formation formed under warmer and more humid climate conditions. These findings reflect a global climate of a cold and dry period from the late Eocene to early Oligocene, and a short warming period in the late Oligocene.

scholarly journals Intensified aridity in the Qaidam Basin during the Middle Miocene: constraints from ostracod, stable isotope, and weathering records

2017 ◽  
Vol 54 (3) ◽  
pp. 242-256 ◽  
Author(s):  
Bowen Song ◽  
Junliang Ji ◽  
Chaowen Wang ◽  
Yadong Xu ◽  
Kexin Zhang
Keyword(s):  
Stable Isotope ◽  
Tibetan Plateau ◽  
Chemical Weathering ◽  
Middle Miocene ◽  
Qaidam Basin ◽  
Global Climate ◽  
The Tibetan Plateau ◽  
Tectonic Events ◽  
Regional Tectonic ◽  
Climate Evolution

The thick and continuous Cenozoic successions in the Qaidam Basin provide an excellent paleoclimate archive. Here, we focus on the ostracod fauna, stable isotope records, and paleoweathering indices from a well-dated Cenozoic sedimentary section in the Qaidam Basin, to develop an understanding of Middle Miocene aridification in central Asia. Microfossil analyses suggest that the ostracod species diversity decreased suddenly after 13.3 Ma, and that the dominant ostracod genus shifted from Ilyocypris to Cyprideis. Stable isotope data from ostracod valves have displayed abrupt positive shifts of 3.75‰ in δ18O values and 5.28‰ in δ13C values since 13.3 Ma. The chemical index of weathering (CIW) and K2O/Na2O ratios decrease markedly after 13.3 Ma, reflecting a significant decrease in chemical weathering intensity. These combined and consistent observations suggest that the Qaidam Basin has experienced increased aridification since 13.3 Ma. The dating was obtained directly from previous magnetostratigraphic studies and can be correlated accurately with global climate evolution and regional tectonic events. A comparison of these results with global paleoclimatic records and previous geologic studies of the Tibetan Plateau revealed that global cooling, rather than uplift of the Tibetan Plateau, played a key role in the drying of the Qaidam Basin at approximately 13 Ma.

scholarly journals Climate Transition from Warm-Dry to Warm-Wet in Eastern Northwest China

Atmosphere ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 548
Author(s):  
Jinhu Yang ◽  
Qiang Zhang ◽  
Guoyang Lu ◽  
Xiaoyun Liu ◽  
Youheng Wang ◽  
...  
Keyword(s):  
Temperature Change ◽  
Water Resource Management ◽  
Yellow River ◽  
Asian Summer Monsoon ◽  
Coupled Model ◽  
Research Programme ◽  
Northwest China ◽  
Humid Climate ◽  
Synergistic Enhancement ◽  
Climate Transition

During the second half of the 20th century, eastern Northwest China experienced a warming and drying climate change. To determine whether this trend has continued or changed during the present century, this study systematically analyzes the characteristics of warming and dry–wet changes in eastern Northwest China based on the latest observational data and World Climate Research Programme (WCRP) Coupled Model Intercomparison Project Phase 6 (CMIP6) collection data. The results show that eastern Northwest China has warmed continuously during the past 60 years with a sudden temperature change occurring in the late 1990s. However, the temperature in the 2000s decreased slowly, and that in the 2010s showed a warming trend. The amount of precipitation began to increase in the late 1990s, which indicates a contemporary climate transition from warm-dry to warm-wet in eastern Northwest China. The contribution of precipitation to humidity is significantly more than that of temperature. Long-term and interannual variations dominate the temperature change, with the contribution of the former much stronger than that of the latter. However, interannual variation dominates the precipitation change. The warming accelerates from period to period, and the temperature spatial consistently increased during the three most recent climatic periods. The precipitation decreased from 1961–1990 to 1981–2010, whereas its spatial consistency increased from 1981–2010 to 1991–2019. The significant warming and humidification which began in the late 1990s and is expected to continue until the end of the 21st century in the medium emission scenario. However, the current sub-humid climate will not easily be changed. The warming could cause a climate transition from warm temperate to subtropical by 2040. The dry-to-wet climate transition in eastern Northwest China could be related to a synergistic enhancement of the East Asian summer monsoon and the westerly circulation. This research provides a scientific decision-making basis for implementing western development strategies, ecological protection, and high-quality development of the Yellow River Basin Area as well as that for ecological construction planning and water resource management of eastern Northwest China.

scholarly journals Ensemble models on palaeoclimate to predict India's groundwater challenge

2013 ◽  
Vol 2 (3) ◽  
Author(s):  
Partha Sarathi Datta
Keyword(s):  
Climate Change ◽  
Climate Models ◽  
Global Climate ◽  
Global Climate Models ◽  
Humid Climate ◽  
Ensemble Models ◽  
North West ◽  
The Past ◽  
The North ◽  
14C Age

In many parts of the world, freshwater crisis is largely due to increasing water consumption and pollution by rapidly growing population and aspirations for economic development, but, ascribed usually to the climate. However, limited understanding and knowledge gaps in the factors controlling climate and uncertainties in the climate models are unable to assess the probable impacts on water availability in tropical regions. In this context, review of ensemble models on δ18O and δD in rainfall and groundwater, 3H- and 14C- ages of groundwater and 14C- age of lakes sediments helped to reconstruct palaeoclimate and long-term recharge in the North-west India; and predict future groundwater challenge. The annual mean temperature trend indicates both warming/cooling in different parts of India in the past and during 1901–2010. Neither the GCMs (Global Climate Models) nor the observational record indicates any significant change/increase in temperature and rainfall over the last century, and climate change during the last 1200 yrs BP. In much of the North-West region, deep groundwater renewal occurred from past humid climate, and shallow groundwater renewal from limited modern recharge over the past decades. To make water management to be more responsive to climate change, the gaps in the science of climate change need to be bridged.

Monitoring Cenozoic climate evolution of northeastern Tibet: stable isotope constraints from the western Qaidam Basin, China

2008 ◽  
Vol 98 (5) ◽  
pp. 1063-1075 ◽  
Author(s):  
Andrea B. Rieser ◽  
Ana-Voica Bojar ◽  
Franz Neubauer ◽  
Johann Genser ◽  
Yongjiang Liu ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Qaidam Basin ◽  
Northeastern Tibet ◽  
Western Qaidam Basin ◽  
Climate Evolution

Trace and rare earth element geochemistry of Jurassic mudstones in the northern Qaidam Basin, northwest China

Geochemistry ◽  
2012 ◽  
Vol 72 (3) ◽  
pp. 245-252 ◽  
Author(s):  
Jian Cao ◽  
Ming Wu ◽  
Yan Chen ◽  
Kai Hu ◽  
Lizeng Bian ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Element ◽  
Earth Element ◽  
Qaidam Basin ◽  
Northwest China ◽  
Element Geochemistry

scholarly journals Application of Multiple Approaches to Investigate the Hydrochemistry Evolution of Groundwater in an Arid Region: Nomhon, Northwestern China

Water ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1667 ◽  
Author(s):  
Nuan Yang ◽  
Guangcai Wang ◽  
Zheming Shi ◽  
Dan Zhao ◽  
Wanjun Jiang ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Qaidam Basin ◽  
Groundwater Resources ◽  
Atmospheric Precipitation ◽  
Northwest China ◽  
Major And Trace Elements ◽  
Alluvial Fan ◽  
Hydrogeochemical Processes ◽  
Recharge Sources ◽  
Gypsum Precipitation

Groundwater is a critical water resource for human survival and economic development in arid and semi-arid areas. It is crucial to understand the groundwater circulation and hydrochemical evolution for sustainable management and utilization of groundwater resources in those areas. To this end, an investigation of the hydrochemical characteristics of surface water and groundwater was conducted in Nomhon, an arid area located in the Qaidam Basin, northwest China, by using hydrochemical (major and trace elements) and stable isotopes (δD and δ18O) approaches. Stable isotopes and ion ratios were analyzed to determine the recharge sources, hydrochemistry characteristics, and major hydrogeochemical processes. Meanwhile, inverse geochemistry modeling was applied to quantitatively determine the mass transfer of hydrogeochemical processes. The results showed that groundwater in the study area is mainly recharged by atmospheric precipitation in mountainous areas, and the groundwater in the center of basin might originate from ancient water in cold and humid environments. Along the groundwater flow path, the TDS of groundwater increased gradually from fresh to salty (ranging from 462.50 to 19,604.40 mg/L), and the hydrochemical type changed from Cl·HCO3–Na·Mg·Ca to Cl–Na. Groundwater chemical composition and mass balance modeling results indicated that from alluvial fan to lacustrine plain, the main hydrogeochemical processes changed from the dissolution of halite and albite and the precipitation of dolomite and kaolinite to the dissolution of halite and gypsum, precipitation of calcite, redox (SO42− reduction), and cation exchange. This study would be helpful for water resources management in this area and other similar areas.

scholarly journals The Jurassic of Skåne, southern Sweden

2003 ◽  
Vol 1 ◽  
pp. 527-541 ◽  
Author(s):  
Anders Ahlberg ◽  
Ulf Sivhed ◽  
Mikael Erlström
Keyword(s):  
Clay Mineralogy ◽  
Depositional Environments ◽  
Burial Diagenesis ◽  
Sea Level Changes ◽  
Humid Climate ◽  
Alluvial Deposits ◽  
Tectonic Zone ◽  
Marine Strata ◽  
Coal Beds ◽  
Shallow Marine Sediments

In Sweden, Jurassic strata are restricted to Skåne and adjacent offshore areas. Jurassic sedimentary rocks predominantly comprise sandy to muddy siliciclastics, with subordinate coal beds and few carbonate-rich beds. During Mesozoic times, block-faulting took place in the Sorgenfrei– Tornquist Zone, a tectonic zone which transects Skåne in a NW–SE direction. The Jurassic depositional environments in Skåne were thus strongly influenced by uplift and downfaulting, and to some extent by volcanism. Consequently, the sedimentary record reveals evidence of numerous transgressions, regressions and breaks in sedimentation. Relative sea-level changes played a significant role in controlling the facies distribution, as deposition mainly took place in coastal plain to shallow shelf environments. The alluvial deposits in Skåne include floodplain palaeosols, autochthonous coals, overbank sandstones, and stream channel pebbly sandstones. Restricted marine strata comprise intertidal heteroliths with mixed freshwater and marine trace fossil assemblages, and intertidal delta distributary channel sandstones. Shallow marine sediments encompass subtidal and shoreface sandstones with herringbone structures, and bioturbated mudstones with tempestite sandstones. Offshore deposits typically comprise extensively bioturbated muddy sandstones. Floral remains, palaeopedology, clay mineralogy and arenite maturity indicate a warm and humid climate in Skåne throughout the Jurassic, possibly with slightly increasing aridity towards the end of the period. Most Jurassic strata in Skåne have been subjected to mild burial diagenesis, and the petroleum generative window has rarely been reached.

Changes in wind erosion climatic erosivity in northern China from 1981-2016: a comparison of two climate/weather factors of wind erosion models

2021 ◽  
Vol 83 ◽  
pp. 133-146
Author(s):  
F Zhang ◽  
J Wang ◽  
X Zou ◽  
R Mao ◽  
DY Gong ◽  
...  
Keyword(s):  
Wind Erosion ◽  
Qaidam Basin ◽  
Dust Emission ◽  
Northern China ◽  
Northwest China ◽  
Gobi Desert ◽  
Weather Factors ◽  
Weather Factor ◽  
Increasing Trend ◽  
Erosion Equation

Wind erosion is largely determined by wind erosion climatic erosivity. In this study, we examined changes in wind erosion climatic erosivity during 4 seasons across northern China from 1981-2016 using 2 models: the wind erosion climatic erosivity of the Wind Erosion Equation (WEQ) model and the weather factor from the Revised Wind Erosion Equation (RWEQ) model. Results showed that wind erosion climatic erosivity derived from the 2 models was highest in spring and lowest in winter with high values over the Kumtag Desert, the Qaidam Basin, the boundary between Mongolia and China, and the Hulunbuir Sandy Land. In spring and summer, wind erosion climatic erosivity showed decreasing trends in whole of northern China from 1981-2016, whereas there was an increasing trend in wind erosion climatic erosivity over the Gobi Desert from 1992-2011. For the weather factor of the RWEQ model, the difference between northern Northwest China and the Gobi Desert and eastern-northern China was much larger than that of the wind erosion climatic erosivity of the WEQ model. In addition, in contrast to a decreasing trend in the weather factor of the RWEQ model over southern Northwest China during spring and summer from 1981-2016, the wind erosion climatic erosivity of the WEQ model showed a decreasing trend for 1981-1992 and an increasing trend for 1992-2011 over southern Northwest China. According to a comparison between dust emission and wind erosion climatic erosivity, the 2 models have the ability to project changes in future wind erosion in northern China.

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