Salty Deposits - Evaporites across space and time

Uniformitarianism is an essential tenet of geological understanding. Yet, when we look at evaporite volumes and depositional settings across deep time, we see that the diversity of modern evaporite analogues is constrained by a deficit in two conditions, specifically; 1) the current lack of greenhouse eustasy; contemporaneous atmospheric conditions and sea levels are controlled by the earth's current icehouse climate mode and have been for the last 10-12 million years, and 2) the current lack at the plate-edge scale of marine seepage into large hydrographically-isolated oceanic sump basins (Warren, 2010). Both situations circumscribe different hydrologies and eustasies compared to continental-fed in-flows that typify the world's current larger evaporite basins.

Put simply, the rates and amplitudes of seafloor spreading, orogeny and eustasy are not constant across deep time, nor is the climatic system they drive. Extensive marine evaporites require particular tectonic or eustatic conditions to accumulate, conditions that are not present on the world’s modern surface (Warren, 2016). They will be in the future, and they have been many times in the past.

© 2016-2024 Saltwork Consultants Pty Ltd