Search results for " δ18O"

showing 4 items of 4 documents

Thermomineral waters of Greece: geochemical characterization

2020

75 °C). In terms of pH most results vary from 5.5 to 823 °C) ii) warm (23 40 °C) iii) thermal (40 75 °C) and iv) hyperthermal (&gtfew springs show either very low pH (&lt10) proposing serpentinization processes. Regarding TDS concentrations collected waters can be subdivided into low salinity (up to 1.5 g/L) brackish (up to 20 g/L) and saline (up to 43 g/L). The medium high salinities can be justified by mixing with sea water and/or strong waterrock interaction processes. Isotope composition of O and H ranges from 12.7 to +2.7 ‰ SMOW and from 91 to +12 ‰ SMOW respectively and is generally comprised between the Global Meteoric Water Line and the East Mediterranean Meteoric Water Line. Only few water samples show a positive shift for δ18O possibly related to high temperature waterrock interaction processes. Carbon dioxide (18 997000 μmol/mol) or N2 (1100 989000 μmol/mol) or CH4 (&ltMany geothermal areas of Greece are located in regions affected by Miocene or Quaternary volcanism and in continental basins characterised by elevated heat flow. Moreover the majority of them is found along the coast as well as in islands of the Aegean Sea and thus thermal water is often brackish to saline due to marine intrusion into costal aquifer. In the present study almost 300 thermal and cold mineral water samples were collected along the Hellenic territory with their physicochemical parameters (temperature pH electrical conductivity and Eh) and the amount of bicarbonates (titration with 0.1N HCl) being determined in situ. Additionally gases found either in free or dissolved phase were sampled. Both water and gas samples were analysed at the INGVPa laboratories for major ions (Ion Chromatography) silica (Inductively Coupled Plasma Optical Emission Spectrometry) chemical composition of free and dissolved gases (Gas Chromatography) water isotopes (O and H) and carbon and helium isotopes of free and dissolved gases (Mass Spectrometry). The temperature of the investigated waters ranges from 6.5 to 98°C pH from 1.96 to 11.98 whilst Total Dissolved Solids (TDS) from 0.06 to 43 g/L. Based on the temperature parameter waters can be divided into four groups: i) cold (&lt0.5 913000 μmol/mol) are the prevailing gas species found in the studied sites. The δ13CCO2 values ranged from 20.1 to +8.5 ‰ whilst the isotope ratio of He from 0.21 to 6.71 R/RA.4) suggesting interaction with H2Srich gases or very high pH values (&gtSettore GEO/08 - Geochimica E Vulcanologia
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(Table 1) Stable oxygen and carbon isotopic ratios of tree rings, and tree ring width of white spruce (Picea glauca), Ennadai Lake

2012

Stable isotope ratios from tree rings and peatland mosses have become important proxies of past climate variations. We here compare recent stable carbon and oxygen isotope ratios in cellulose of tree rings from white spruce (Picea glauca), growing near the arctic tree line; and cellulose of Sphagnum fuscum stems, growing in a hummock of a subarctic peatland, in west-central Canada. Results show that carbon isotopes in S. fuscum correlate significantly with July temperatures over the past ~20 yr. The oxygen isotopes correlate with both summer temperature and precipitation. Analyses of the tree-ring isotopes revealed summer temperatures to be the main controlling factor for carbon isotope var…

Picea glauca standard deviationPicea glauca δ18O tree ringsPicea glauca tree ring widthInternational Polar Year (2007-2008) (IPY)tree ring widthtree ringsSample IDTree ring samplingPicea glauca δ13C tree ringsInternational Polar Year 2007 2008 IPYδ13CEarth System Researchstandard deviationPicea glaucaδ18O
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Stable isotopic composition of three foraminifera species in ODP Hole 160-963D

2020

Carbon-rich layers exist at both sides of the Mediterranean Sea sedimentary record and are called sapropels and organic rich layers (ORLs), respectively in the eastern and western basins. They have different levels of organic carbon accumulation and seafloor oxygen deprivation. The most recent sapropel and ORL deposition have a different timing, 10.8-6.1 and 14.5-9.0 ka respectively. Here we investigate oxygen isotopic records of three foraminifera species that occupy different habitats within the Sicily Channel water column since ~ 12.0 ka, thus in the sill between the eastern and western Mediterranean basins. These data are ice volume-corrected, to get information on water masses density …

Leg160Uvigerina spp. δ13CORLNeogloboquadrina incompta δ13C9.2 ka event8 2 ka eventDEPTH sediment/rockNeogloboquadrina incomptaGlobigerinoides ruber δ13CAGE8.2 ka event9 2 ka eventDSDP/ODP/IODP sample designationδ18ODSDP ODP IODP sample designationSample code/labelGlobigerinoides ruber δ18OSapropel S1Globigerinoides ruberJoides ResolutionUvigerina spp. δ18OSample code labelDrilling/drill rigDrilling drill rigsediment rockLIWDEPTHUvigerina sppδ13CEarth System ResearchNeogloboquadrina incompta δ18O
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Monthly Bonaire coral Sr/Ca and oxygen isotope data from 118 kyr ago (coral BON-5-D)

2015

The end of the last interglacial period, ~118 kyr ago, was characterized by substantial ocean circulation and climate perturbations resulting from instabilities of polar ice sheets. These perturbations are crucial for a better understanding of future climate change. The seasonal temperature changes of the tropical ocean, however, which play an important role in seasonal climate extremes such as hurricanes, floods and droughts at the present day, are not well known for this period that led into the last glacial. Here we present a monthly resolved snapshot of reconstructed sea surface temperature in the tropical North Atlantic Ocean for 117.7±0.8 kyr ago, using coral Sr/Ca and d18O records. W…

CaribClim_Coral_2006Integrierte Analyse zwischeneiszeitlicher Klimadynamik INTERDYNAMIKDrilling/drill rigCalculated see reference(s)Drilling drill rigOptima 3300RPerkin ElmerIntegrierte Analyse zwischeneiszeitlicher Klimadynamik (INTERDYNAMIK)ICP OESMass spectrometer Finnigan MAT 251Diploria strigosaDiploria strigosa δ18OCalculatedEarth System ResearchCenter for Marine Environmental Sciences MARUMsee reference sICP-OES Perkin-Elmer Optima 3300RInternal coral chronologyδ18ODiploria strigosa Strontium/Calcium ratioStrontium Calcium ratioCenter for Marine Environmental Sciences (MARUM)
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