Istituto di Scienze Marine     
Vigliotti L., Asioli A., Bergami C., Capotondi L., Piva A. Magnetic properties of the youngest sapropel S1 in the Ionian and Adriatic Sea: inference for the timing and mechanism of sapropel formation. In: italian journal of geosciences, vol. 130 (1) pp. 106 - 118. SOC GEOLOGICA ITALIANA, UNIV DEGLI STUDI LA SAPIENZA, DIPART SCI DELLA TERRA, PIAZZALE ALDO MORO 5, ROME, I-00185, ITALY, 2011.
The youngest sapropel SI has been investigated by a multiproxy study on a core (ET99-M11) collected in the western Ionian Sea at a water depth of 2800 m, which is considered to represent anoxic conditions in the eastern Mediterranean at the time of sapropel formation. Selected geochemical parameters (TOC, Ba/Al, MnO) as well as micropaleontological analysis (planktic foraminifera), rock magnetic data, and C-14 dating indicate that anoxic conditions prevailed between 10.4 and 5.7 ka BP. The comparison among the different proxies indicates that rock magnetic parameters can be unambiguously used to precisely identify sapropel layers, even if no iron sulphide phases have been precipitated as a bi-product of diagenetic breakdown of organic matter. By using the magnetic parameters as indicators of paleoredox conditions we compare the results with cores collected in the central and southern Adriatic Sea at different water depths. A shorter duration (9.6/9-7/6.8 ka BP) of the sapropel Si was observed in the deepest southern part of the basin and in the Meso Adriatic Depression whereas suboxic conditions continued in cores collected at very shallow water depth of 56 m along the western margin of the basin. The formation of the Adriatic Deep Water driven by decreasing solar radiation output is considered responsible for the interruption and end of sapropel formation.
DOI: 10.3301/IJG.2010.29
Subject Sapropel
Magnetic Properties
Central Mediterranean

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