Sea level and climate forcing of the Sr isotope composition of lateMioceneMediterranean marine basins

Abstract

Sr isotope records from marginal marine basins track the mixing between seawater and local continental runoff, potentially recording the effects of sea level, tectonic, and climate forcing in marine fossils and sediments. Sr/ 86 Sr analyses from the astronomically tuned Lower Evaporites in the central Apennines (Italy) allow us to explore the effect of glacio-eustatic sea level and precipitation changes on 87 Sr/ 86 Sr. Most variation in our data can be explained by changes in sea level, with greatest negative excursions from global seawater values occurring during relative sea level lowstands, which generally coincided with arid conditions in the Mediterranean realm. We suggest that this greater sensitivity to lowered sea level compared with higher runoff could relate to the inverse relationship between Sr concentration and river discharge. Variations in the residence time of groundwater within the karst terrain of the circum-Mediterranean region during arid and wet phases may help to explain the single (robust) occurrence of a negative excursion during a sea level highstand, but this explanation remains speculative without more detailed paleoclimatic data for the region.

Deep-seated hydrocarbons in the seep “Brecciated Limestones” of the Maiella area (Adriatic foreland basin): Evaporitic sealing and oil re-mobilization effects linked to the drawdown of the Messinian Salinity Crisis

“…The MSC, which was responsible for the deposition of the "Primary Lower Gypsum" and the post-evaporitic Lago-Mare succession in the area (Bonarelli, 1951;Di Napoli Alliata, 1964;Crescenti et al, 1969a, b;Catenacci, 1974;Clermontè and Geisler, 1977;Patacca et al, 1992;Cipollari et al, 1999Cipollari et al, , 2003Gliozzi et al, 2002;Crescenti et al, 2002;Centamore and Nisio, 2003;Cosentino et al, 2005Cosentino et al, , 2011Cosentino et al, , 2013Sampalmieri et al, 2008;Sampalmieri et al, 2010;Iadanza et al, 2013;Schildgen et al, 2014), was followed by the Early Pliocene flooding event that marked the end of the crisis and was responsible for the deposition of bathyal clays (MPL1-lower MPL2 biozones; Cipollari et al, 2003).…”

Precessional variability of87Sr/86Sr in the late Miocene Sorbas Basin: An interdisciplinary study of drivers of interbasin exchange

“…Strontium isotopes are an elegant tool for investigating interbasin connectivity as they are sensitive to changing water sources. This tool has been used to reconstruct the connectivity of basins with limited connections to the open ocean on a variety of scales (e.g., Baltic Sea, San Francisco Bay, and Mississippi Delta [ Ingram and Depaolo , ; Andersson et al , ]) including the restriction of the Mediterranean from the Atlantic during the Messinian Salinity Crisis (MSC) [ Topper et al , ; Roveri et al , ; Schildgen et al , ; Reghizzi et al , ]. Published pre‐MSC Sr isotope records from some of the Mediterranean's marginal basins (i.e., Southern Turkey [ Flecker and Ellam , ], the Adriatic [ Montanari et al , ], and Tyrrhenian Sea [ Müller and Mueller , ]) deviate from global ocean Sr values up to 3.5 Myr before the first MSC evaporites were precipitated [ Flecker and Ellam , ].…”

Estuarine Lago Mare fauna from the Tertiary Piedmont Basin indicates episodic Atlantic/Mediterranean exchange during the final stage of the Mediterranean Salinity Crisis

“…Prior to the MSC, 87 Sr/ 86 Sr values of Mediterranean biogenic carbonates generally follow open ocean values until~6.1 Ma, reflecting a well-established connection to the Atlantic (Fig. 5; McArthur et al, 2001;Roveri et al, 2014a;Schildgen et al, 2014). Depleted 87 Sr/ 86 Sr values are only reported from a few marginal basins which became restricted at different times due to local tectonic uplift (seeSchildgen et al, 2014 for a detailed discussion).…”

“…5; McArthur et al, 2001;Roveri et al, 2014a;Schildgen et al, 2014). Depleted 87 Sr/ 86 Sr values are only reported from a few marginal basins which became restricted at different times due to local tectonic uplift (seeSchildgen et al, 2014 for a detailed discussion). The TPB, however, remained well connected to the Mediterranean prior to evaporite deposition, sustaining a diverse marine fauna(Sturani, 1975;Dela Pierre et al, 2011;Violanti et al, 2011).…”