124 D21. Recent Advances in Sedimentology and Stratigraphy

Monday, 23 September 2024
1:30 PM - 5:30 PM
207B

EVAPORITES IN THE DANAKIL DEPRESSION (AFAR, ETHIOPIA): FROM RECENT SALT LAB TO DEEP DRILLING

Paper number: 124-7
Program: Technical Sessions
Time: 2:50 PM – 3:05 PM

Authors

Abstract

The understanding of large evaporite deposits is poor and still controversial due to the absence of modern analogues. Especially, the mechanisms of formation, hydrological and environmental conditions, geobiosphere interactions in salt deposits, as well as rates of evaporite precipitation remain highly ambiguous. The Danakil Depression, localized in the Afar rift (northern Afar, Ethiopia) and being close to continental break-up, host thick Pleistocene to Holocene evaporites with deposition continuing today. As such, the Danakil Depression forms a unique Recent lab to study salt formation, gypsum deposition and its interaction with tectonic processes, volcanic events, eustatic sea-level change and the geobiosphere. The Recent age of the Danakil evaporites along with the availability of very high temporal resolution records offer new insights in the formation of those enigmatic deposits.

Multi-proxy analyses on cores in the central part of the Danakil Depression witness restricted marine conditions since the last Late Pleistocene marine incursion resulting in the near-desiccation of the basin with the deposition of thick halite and Potash deposits. The Recent basin floor represents a large active halite-floored saline pan with the presence of hypersaline lakes but also hydrothermal brine pools, sulfuric acidic springs, and fumaroles through the direct interaction between magmatism, sedimentary and salt processes. This allows studying life-salt interaction and biogeochemical cycling in polyextreme conditions across geothermal gradients.

Subsurface seismic data show the presence of distinct syn-rift seismo-stratigraphic units probably representing similar evaporite lithologies as observed for the Late Pleistocene until a depth of 2.2 km. However, the origin and nature of those sedimentary units remain to be unveiled. The ICDP ADD-ON project aims to drill through the syn-rift sedimentary record in the central part of the Danakil Depression which will shed new light on the understanding evaporite formation in extreme rift settings and other Salt Giants on Planet Earth.

Geological Society of America Abstracts with Programs. Vol. 56, No. 5

doi: 10.1130/abs/2024AM-403868

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