Earthworm-produced calcite granules: a new terrestrial palaeothermometer?

Versteegh, E. A.A., Black, S. ORCID: https://orcid.org/0000-0003-1396-4821, Canti, M. G. and Hodson, M. E. (2013) Earthworm-produced calcite granules: a new terrestrial palaeothermometer? Geochimica et Cosmochimica Acta, 123. pp. 351-357. ISSN 0016-7037 doi: 10.1016/j.gca.2013.06.020

Abstract/Summary

In this paper we show for the first time that calcite granules, produced by the earthworm Lumbricus terrestris, and commonly recorded at sites of archaeological interest, accurately reflect temperature and soil water δ18O values. Earthworms were cultivated in an orthogonal combination of two different (granule-free) soils moistened by three types of mineral water and kept at three temperatures (10, 16 and 20 ºC) for an acclimatisation period of three weeks followed by transfer to identical treatments and cultivation for a further four weeks. Earthworm-secreted calcite granules were collected from the second set of soils. δ18O values were determined on individual calcite granules (δ18Oc) and the soil solution (δ18Ow). The δ18Oc values reflect soil solution δ18Ow values and temperature, but are consistently enriched by 1.51 (±0.12) ‰ in comparison to equilibrium in synthetic carbonates. The data fit the equation 1000 ln α = [20.21 ± 0.92] (103 T-1) - [38.58 ± 3.18] (R2 = 0.95; n = 96; p < 0.0005). As the granules are abundant in modern soils, buried soils and archaeological contexts, and can be dated using U-Th disequilibria, the developed palaeotemperature relationship has enormous potential for application to Holocene and Pleistocene time intervals.

Item Type	Article
URI	https://reading-pure-test.eprints-hosting.org/id/eprint/32881
Identification Number/DOI	10.1016/j.gca.2013.06.020
Refereed	Yes
Divisions	Science > School of Archaeology, Geography and Environmental Science > Department of Archaeology Science > School of Archaeology, Geography and Environmental Science
Download/View statistics	View download statistics for this item