Triple oxygen isotope variations in precipitation from southeast China and its hydrological significance

2020 ◽  
Author(s):  
Pengzhen Duan ◽  
Sasadhar Mahata ◽  
Lijuan Sha ◽  
Hai Cheng
Keyword(s):  
Oxygen Isotope ◽  
Meteoric Water ◽  
Meteorological Parameters ◽  
Model Simulation ◽  
Optical Measurements ◽  
Water Isotopes ◽  
First Year ◽  
Southeast China ◽  
Excess Loss ◽  
Combined Use

<p>    High precision triple oxygen isotope measurement of meteoric water is a newly added tracer in hydrological and paleoclimate research. However, it is prerequisite to study the controls on precipitation <sup>17</sup>O-excess for proper application of it. Here we report two years highly precise precipitation data from Nanjing, a southeast China station dominated by Asian monsoon. All the water isotopes (δ<sup>17</sup>O, δ<sup>18</sup>O and δD) reported here are based on mass spectrometer measurements and optical measurements (cavity ring-down spectroscopy). Nanjing receives moisture from different vapor sources and experiences different rainout mechanisms during various monsoonal sessions. Combined use of above parameters can help us to delineate processes occurring during evaporation, transport, condensation and re-evaporation. Year to year <sup>17</sup>O-excess variability is observed in the obtained dataset and no notable seasonal variation is observed. However, the <sup>17</sup>O-excess seasonal amplitude is little larger in the first year than the subsequent year. So far, it is known that the precipitation <sup>17</sup>O-excess depends on three values:<sup> 17</sup>O-excess of the source water bodies, amount of <sup>17</sup>O-excess gain during evaporation and <sup>17</sup>O-excess loss during raindrops evaporation. During dry months <sup>17</sup>O-excess gain is balanced by <sup>17</sup>O-excess loss, which might lead to the near absence of seasonal cycle at Nanjing. From the comparison of observed data and model simulation, the amount of re-evaporation on falling raindrop is estimated to be about 10% at Nanjing. In addition, correlation with available meteorological parameters has been discussed. Except temperature no significant correlation has been found with other metrological variables (relative humidity and rainfall amount). This study will serve as a baseline to understand some of issues in paleoclimate that have puzzled the scientific community for years.</p>

scholarly journals Seasonal and Inter-Annual Variations of Stable Isotopic Characteristics of Rainfall and Cave Water in Shennong Cave, Southeast China, and Its Paleoclimatic Implication

2021 ◽  
Vol 9 ◽  
Author(s):  
Ye Tian ◽  
Haiwei Zhang ◽  
Rui Zhang ◽  
Fan Zhang ◽  
Zeyuan Liang ◽  
...  
Keyword(s):  
Oxygen Isotope ◽  
Summer Monsoon ◽  
Meteoric Water ◽  
El Nino ◽  
Monsoon Precipitation ◽  
Southeast China ◽  
Water Line ◽  
Moisture Source ◽  
Meteoric Water Line ◽  
June July

Speleothem calcite stable oxygen isotope (δ18OC) is one of the most widely used proxies in paleoclimate research, and understanding its seasonal-annual variability is very significant for palaeoclimate reconstruction. Five-year precipitation and karst cave water from 2016 to 2021 were monitored in Shennong cave, Jiangxi Province, Southeast China. The local meteoric water line (LMWL) is δD = 8.20 × δ18O + 13.34, which is similar to the global meteoric water line. The stable hydrogen and oxygen isotope (δD and δ18O) characteristics of precipitation and cave water were studied. δ18O and δD of precipitation and cave water show obvious seasonal variations. Lower precipitation δ18O and δD generally occur during summer and autumn compared with higher δ18O and δD values during winter and spring. Meanwhile, low precipitation δ18O values do not only appear in June–July when precipitation is the highest of the year but also appear in August–September when precipitation is limited. The back-trajectory analysis of monsoon precipitation moisture sources shows that the moisture uptake regions vary little on inter-annual scales; the water vapor of rainfall in June–July comes from the South China Sea and the Bay of Bengal, while the moisture source in August–September is mainly from the West Pacific and local area. The El Niño-Southern Oscillation is an important factor affecting the value of δ18O by modulating the percentage of summer monsoon precipitation in the annual precipitation and moisture source. The relationship between amount-weighted monthly mean precipitation δ18O and Niño-3.4 index shows that the East Asian summer monsoon (EASM) intensifies during La Niña phases, resulting in more precipitation in monsoon season (May to September, MJJAS) and lower δ18O values, and vice versa during El Niño phases.

Use of stable water isotopes to identify hydrological processes of meteoric water in montane catchments

2015 ◽  
Vol 29 (23) ◽  
pp. 4957-4967 ◽  
Author(s):  
Tsung-Ren Peng ◽  
Kuan-Yu Chen ◽  
Wen-Jun Zhan ◽  
Wan-Chung Lu ◽  
Lun-Tao John Tong
Keyword(s):  
Meteoric Water ◽  
Hydrological Processes ◽  
Water Isotopes ◽  
Stable Water Isotopes

Jurassic and Cretaceous clays of the northern and central North Sea hydrocarbon reservoirs reviewed

Clay Minerals ◽  
2006 ◽  
Vol 41 (1) ◽  
pp. 151-186 ◽  
Author(s):  
M. Wilkinson ◽  
R. S. Haszeldine ◽  
A. E. Fallick
Keyword(s):  
Oxygen Isotope ◽  
North Sea ◽  
Meteoric Water ◽  
Threshold Temperature ◽  
Common Belief ◽  
The North ◽  
Wide Range ◽  
The North Sea ◽  
Uplift And Erosion ◽  
Central North Sea

AbstractThe principal clays of the northern and central North Sea are illite (sometimes with interlayered smectite) and kaolin. Chlorite is only locally important. Although it has been proposed that kaolin within North Sea sandstones is detrital in origin, the majority of workers have concluded that it is authigenic, largely the product of feldspar alteration. Kaolin is found within a wide range of sedimentary settings (and within shales) apparently defying the notion that kaolin is an indicator of meteoric water deposition. Within sandstones, the earliest authigenic kaolin has a vermiform morphology, the distribution of which is controlled by the availability of detrital mica to act as a nucleus, and the composition of the post-depositional porewaters. This vermiform kaolin formed in meteoric water, the presence of which is easily accounted for below sub-aerial exposure surfaces in non-marine formations, and below unconformities over marine units. In fully marine sands, and even marine shale units, kaolin still occurs. It has therefore been suggested that even these locations have been flushed with meteoric water.Early vermiform kaolin recrystallizes to a more blocky morphology as burial proceeds, at least in the Brent Group. Blocky kaolin has been reported as growing before, synchronously with, and after the formation of quartz overgrowths, though oxygen isotope studies support low-temperature growth, pre-quartz. Blocky kaolin may form during meteoric flushing associated with lower Cretaceous uplift and erosion, though it is found in fault blocks that are thought to have remained below sea level. Here, the kaolin may form in stagnant meteoric water, relics of the post-depositional porewater. It has also been proposed that the blocky kaolin grew in ascending basinal waters charged with carboxylic acids and CO2, though this hypothesis is not supported by stable oxygen isotope data. Some of the blocky kaolin is dickite, the stable polymorph above ∼100°C.Fibrous illite occurs almost ubiquitously within the clastic sediments of the North Sea. An early pore-lining phase has been interpreted as both infiltrated clastic clay, and as an early diagenetic phase. Early clays may have been quite smectite-rich illites, or even discrete smectites. Later, fibrous illite is undoubtedly neoformed, and can degrade reservoir quality significantly. Both within sandstones and shales, there is an apparent increase in the K content deeper than 4 km of burial, which could be due to dilution of the early smectite-rich phase by new growth illite, or to the progressive illitization of existing I-S. Much of the ‘illite’ that has been dated by the K-Ar method may therefore actually be I-S.The factors that control the formation of fibrous illite are only poorly known, though temperature must play a role. Illite growth has been proposed for almost the entire range of diagenetic temperatures (e.g. 15–20°C, Brent Group; 35–40°C, Oxfordian Sand, Inner Moray Firth; 50–90°C, Brae formation; 100–110°C, Brent Group; 130–140°C, Haltenbanken). It seems unlikely that there is a threshold temperature below which illite growth is impossible (or too slow to be significant), though this is a recurring hypothesis in the literature. Instead, illite growth seems to be an event, commonly triggered by oil emplacement or another change in the physiochemical conditions within the sandstone, such as an episode of overpressure release. Hence fibrous illite can grow at any temperature encountered during diagenesis.Although there is an extensive dataset of K-Ar ages of authigenic illites from the Jurassic of the North Sea, there is no consensus as to whether the data are meaningful, or whether the purified illite samples prepared for analysis are so contaminated with detrital phases as to render the age data meaningless. At present it is unclear about how to resolve this problem, though there is some indication that chemical micro-analysis could help. It is a common belief that illite ages record the timing of oil charge, and so can be used to calibrate basin models.Grain-coating Fe-rich chlorite cements can preserve exceptional porosity during burial. They are found in marginal marine sandstones, formed during diagenesis from precursor Fe-rich clays such as berthierine or verdine.

Oxygen isotope compositions of phosphate from arvicoline teeth and Quaternary climatic changes, Gigny, French Jura

2004 ◽  
Vol 62 (2) ◽  
pp. 172-182 ◽  
Author(s):  
Nicolas Navarro ◽  
Christophe Lécuyer ◽  
Sophie Montuire ◽  
Cyril Langlois ◽  
François Martineau
Keyword(s):  
Oxygen Isotope ◽  
Air Temperature ◽  
Isotope Fractionation ◽  
Meteoric Water ◽  
Ice Core ◽  
Climatic Changes ◽  
Oxygen Isotope Fractionation ◽  
Air Temperatures ◽  
French Jura ◽  
Fractionation Equation

Oxygen isotope compositions of biogenic phosphates from mammals are widely used as proxies of the isotopic compositions of meteoric waters that are roughly linearly related to the air temperature at high- and mid-latitudes. An oxygen isotope fractionation equation was determined by using present-day European arvicoline (rodents) tooth phosphate: δ18Op = 20.98(±0.59) + 0.572(±0.065) δ18Ow. This fractionation equation was applied to the Late Pleistocene karstic sequence of Gigny, French Jura. Comparison between the oxygen isotope compositions of arvicoline tooth phosphate and Greenland ice core records suggests to reconsider the previously established hypothetical chronology of the sequence. According to the δ18O value of meteoric water–mean air temperature relationships, the δ18O value of arvicoline teeth records variations in mean air temperatures that range from 0° to 15°C.

scholarly journals Dew-induced transpiration suppression impacts the water and isotope balances of Colocasia leaves

2017 ◽  
Author(s):  
Cynthia Gerlein-Safdi ◽  
Paul P.G. Gauthier ◽  
Kelly K. Caylor
Keyword(s):  
Water Potential ◽  
Meteoric Water ◽  
Isotope Composition ◽  
Leaf Water ◽  
Water Isotopes ◽  
Foliar Uptake ◽  
Tropical Plant ◽  
Series Of Experiments ◽  
Dew Deposition ◽  
Transpiration Suppression

AbstractFoliar uptake of water from the surface of leaves is common when rainfall is scarce and non-meteoric water such as dew or fog is more abundant. However, many species in more mesic environments have hydrophobic leaves that do not allow the plant to uptake water. Unlike foliar uptake, all species can benefit from dew- or fog-induced transpiration suppression, but despite its ubiquity, transpiration suppression has so far never been quantified. Here, we investigate the effect of dew-induced transpiration suppression on the water balance and the isotope composition of leaves via a series of experiments. Characteristically hydrophobic leaves of a tropical plant, Colocasia esculenta, are misted with isotopically enriched water to reproduce dew deposition. This species does not uptake water from the surface of its leaves. We measure leaf water isotopes and water potential and find that misted leaves exhibit a higher water potential (p < 0.05) and a more depleted water isotope composition than dry leaves (p < 0.001), suggesting a ~30% decrease in transpiration rate (p < 0.001) compared to control leaves. We propose three possible mechanisms governing the interaction of water droplets with leaf energy balance: increase in albedo from the presence of dew droplets, decrease in leaf temperature from the evaporation of dew, and local decrease in vapor pressure deficit. Comparing previous studies on foliar uptake to our results, we conclude that transpiration suppression has an effect of similar amplitude, yet opposite sign to foliar uptake on leaf water isotopes.

Foehn-like Wind in the Mountains of Southeastern Brazil as Seen by the Eta Model Simulation

2020 ◽  
Author(s):  
Pablo Luis Antico ◽  
Sin Chan Chou ◽  
Marcelo Enrique Seluchi ◽  
Gustavo Sueiro
Keyword(s):  
Time Series ◽  
Numerical Simulations ◽  
Meteorological Parameters ◽  
Model Simulation ◽  
Sao Paulo ◽  
Observational Evidence ◽  
Southeastern Brazil ◽  
Regional Patterns ◽  
Eta Model ◽  
The City

Abstract The present study gives evidence of the occurrence of foehn-like wind on the eastern slopes of the mountains at Southeastern Brazil. A particular case was detected based on observational evidence on 4 July 2015 near the city of Cruzeiro, state of Sao Paulo, on the Serra da Mantiqueira mountains. Results obtained from numerical simulations are consistent with the foehn wind occurrence deducted from the analysis of regional patterns and time series of selected meteorological parameters.

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