The historical impact of anthropogenic air-borne sulphur on the Pleistocene rock art of Sulawesi

This is a Preprint and has not been peer reviewed. The published version of this Preprint is available: https://doi.org/10.1038/s41598-022-25810-1. This is version 1 of this Preprint.

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Authors

Michael Gagan, Halmar Halide, Raden Permana, Rustan Lebe, Gavin Dunbar, Alena K Kimbrough, Heather Scott-Gagan, Dan Zwartz, Wahyoe Hantoro

Abstract

The Maros-Pangkep karst in southwest Sulawesi, Indonesia, contains some of the world’s oldest rock art. However, the Pleistocene images survive only as weathered patches of pigment on exfoliated limestone surfaces. Salt efflorescence underneath the case-hardened limestone substrate causes spall-flaking, and it has been proposed that the loss of artwork has accelerated over recent decades. Here, we utilise historical photographs and superposition constraints to show that the bulk of the damage was present before 1950 CE, and describe the role of anthropogenic sulphur emissions in promoting gypsum-salt efflorescence and rock art decay. The rock art shelters have been exposed to domestic fire-use and intensive rice cultivation with post-harvest burning of straw for hundreds (if not thousands) of years, both of which release chemically reactive sulphur oxides for gypsum formation, with cumulative effects. Analysis of time-lapse photography indicates that the rate of rock art loss may be on the decline, consistent with the history of fire-use in southwest Sulawesi. At present, vandalism and sulphur emissions from diesel-powered traffic and cement-based infrastructure development constitute localised threats. Our findings indicate that there are grounds for being cautiously optimistic that targeted conservation measures will ensure the longevity of some of our oldest artistic treasures.

DOI

https://doi.org/10.31223/X5MD2W

Subjects

Earth Sciences, Environmental Indicators and Impact Assessment, Environmental Sciences, Geochemistry, Natural Resources and Conservation

Keywords

Sulawesi, rock art, degradation, sulphur emissions, gypsum efflorescence

Dates

Published: 2022-05-31 07:48

Last Updated: 2022-05-31 14:48

License

CC BY Attribution 4.0 International

Additional Metadata

Conflict of interest statement:
None

Data Availability (Reason not available):
Essential data are available in the preprint

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