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Dan Xie - One of the best experts on this subject based on the ideXlab platform.

Jonathan C Aitchison - One of the best experts on this subject based on the ideXlab platform.

Mark O Cuthbert - One of the best experts on this subject based on the ideXlab platform.

  • dripwater organic matter and trace element geochemistry in a semi arid karst environment implications for speleothem Paleoclimatology
    Geochimica et Cosmochimica Acta, 2014
    Co-Authors: Helen Rutlidge, Mark O Cuthbert, Andy Baker, P W Graham, Martin S Andersen, Christopher E Marjo, Gabriel C Rau, Hamid Roshan, Monika Markowska
    Abstract:

    A series of four short-term infiltration experiments which revealed hydrochemical responses relevant to semi-arid karst environments were carried out above Cathedral Cave, Wellington, New South Wales (NSW), Australia. Dripwater samples were collected at two sites for trace element and organic matter analysis. Organic matter was characterised using fluorescence and interpreted using a PARAFAC model. Three components were isolated that represented unprocessed, soil-derived humic-like and fulvic-like material, processed humic/fulvic-like material and tryptophan-like fluorescence. Principal Component Analysis (PCA) performed on the entire dataset comprising trace element concentrations and PARAFAC scores revealed two dominant components that were identified as soil and limestone bedrock. The soil component was assigned based on significant contributions from the PARAFAC scores and additionally included Ba, Cu, Ni and Mg. The bedrock component included the expected elements of Ca, Mg and Sr as well as Si. The same elemental behaviour was observed in recent stalagmite growth collected from the site. Our experiments demonstrate that existing paleoclimate interpretations of speleothem Mg and Sr, developed in regions of positive water balance, are not readily applicable to water limited environments. We provide a new interpretation of trace element signatures unique to speleothems from water limited karst environments.

  • drip water isotopes in semi arid karst implications for speleothem Paleoclimatology
    Earth and Planetary Science Letters, 2014
    Co-Authors: Mark O Cuthbert, Andy Baker, Catherine N Jex, P W Graham, Pauline C Treble, Martin S Andersen, Ian R Acworth
    Abstract:

    Abstract We report the results of the first multi-year monitoring and modelling study of the isotopic composition of drip waters in a semi-arid karst terrane. High temporal resolution drip rate monitoring combined with monthly isotope drip water and rainfall sampling at Cathedral Cave, Australia, demonstrates that drip water discharge to the cave occurs irregularly, and only after occasional long duration and high volume rainfall events, where the soil moisture deficit and evapotranspiration is overcome. All drip waters have a water isotopic composition that is heavier than the weighted mean annual precipitation, some fall along the local meteoric water line, others trend towards an evaporation water line. It is hypothesised that, in addition to the initial rainfall composition, evaporation of unsaturated zone water, as well as the time between infiltration events, are the dominant processes that determine infiltration water isotopic composition. We test this hypothesis using a soil moisture balance and isotope model. Our research reports, for the first time, the potential role of sub-surface evaporation in altering drip water isotopic composition, and its implications for the interpretation of speleothem δ O 18 records from arid and semi-arid regions.

Luba Jansa - One of the best experts on this subject based on the ideXlab platform.

Taylor J Perron - One of the best experts on this subject based on the ideXlab platform.