In:
Nature Communications, Springer Science and Business Media LLC, Vol. 10, No. 1 ( 2019-07-05)
Abstract:
The oxygen isotope composition of speleothems is a widely used proxy for past climate change. Robust use of this proxy depends on understanding the relationship between precipitation and cave drip water δ 18 O. Here, we present the first global analysis, based on data from 163 drip sites, from 39 caves on five continents, showing that drip water δ 18 O is most similar to the amount-weighted precipitation δ 18 O where mean annual temperature (MAT) is 〈 10 °C. By contrast, for seasonal climates with MAT 〉 10 °C and 〈 16 °C, drip water δ 18 O records the recharge-weighted δ 18 O. This implies that the δ 18 O of speleothems (formed in near isotopic equilibrium) are most likely to directly reflect meteoric precipitation in cool climates only. In warmer and drier environments, speleothems will have a seasonal bias toward the precipitation δ 18 O of recharge periods and, in some cases, the extent of evaporative fractionation of stored karst water.
Type of Medium:
Online Resource
ISSN:
2041-1723
DOI:
10.1038/s41467-019-11027-w
Language:
English
Publisher:
Springer Science and Business Media LLC
Publication Date:
2019
detail.hit.zdb_id:
2553671-0
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