PHREATIC OVERGROWTHS ON SPELEOTHEMS (POS): A PALEOCLIMATE PROXY IN THE MEDITERRANEAN SEA

Keywords: Cave, Phreatic Overgrowths on Speleothems, Paleoclimate Proxy, crystalline fabric.
Session Type: Virtual Lightning Paper Abstract
Day: Sunday
Session Start / End Time: 2/27/2022 03:40 PM (Eastern Time (US & Canada)) - 2/27/2022 05:00 PM (Eastern Time (US & Canada))
Room: Virtual 42

Abstract

The study presented here is focused on a particular type of deposits formed inside caves, known as POS (Phreatic Overgrowths on Speleothems), and their role as a new paleoclimate proxy. They grow at sea level in brackish water pools inside caves located in some Mediterranean coastal areas with direct or indirect connection with sea water, therefore, their height is related to sea level of the Mediterranean sea.
The study of POS is based on the data taken about their height and location inside the caves and on the information extracted from their observation in thin section. Mineralogically, POS are constituted by calcite and aragonite (less common) or by a combination of both. They present four groups of crystal fabric: 1) mosaic, including micrite, sparite and microsparite; 2) columnar; 3) fibrous; and 4) fan and feather shape. These individual fabrics or a mixture of some of them can be recognised in thin section.
POS are, consequently, an important proxy that reflects, on the one hand, the direct relationship between their height and paleo sea level and, on the other hand, the indirect relationship between crystalline fabric and environmental and geochemical conditions during their deposition since the Late Miocene.

The study of these deposits can provide valuable paleoclimatic data of the Mediterranean area and might open a new way to supply paleoenvironmental information from this proxy.