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. 2019 Jun 20;9(1):8842.
doi: 10.1038/s41598-019-45308-7.

Two-step closure of the Miocene Indian Ocean Gateway to the Mediterranean

Or M Bialik  1 , Martin Frank  2 , Christian Betzler  3 , Ray Zammit  4 , Nicolas D Waldmann  5
Affiliations

Two-step closure of the Miocene Indian Ocean Gateway to the Mediterranean

Or M Bialik et al. Sci Rep. .

Abstract

The Tethys Ocean was compartmentalized into the Mediterranean Sea and Indian Ocean during the early Miocene, yet the exact nature and timing of this disconnection are not well understood. Here we present two new neodymium isotope records from isolated carbonate platforms on both sides of the closing seaway, Malta (outcrop sampling) and the Maldives (IODP Site U1468), to constrain the evolution of past water mass exchange between the present day Mediterranean Sea and Indian Ocean via the Mesopotamian Seaway. Combining these data with box modeling results indicates that water mass exchange was reduced by ~90% in a first step at ca. 20 Ma. The terminal closure of the seaway then coincided with the sea level drop caused by the onset of permanent glaciation of Antarctica at ca. 13.8 Ma. The termination of meridional water mass exchange through the Tethyan Seaway resulted in a global reorganization of currents, paved the way to the development of upwelling in the Arabian Sea and possibly led to a strengthening of South Asian Monsoon.

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Conflict of interest statement

The authors declare no competing interests.

Figures

Figure 1
Figure 1
Early to Middle Miocene paleogeography of the Mediterranean Sea and western Indian Ocean: Arrows indicate surface circulation patterns,,, with black arrow indicate surface waters and white intermediate to deep waters. Red numbers indicate potential source areas of runoff with positive εNd signatures. Major drainage systems of the northern African continent are marked. The speculated area of the “Gomphotherium landbridge” overlaps with the Mesopotamian Seaway.
Figure 2
Figure 2
ɛNd records of the western Indian Ocean from IODP Site U1468 (this study; Indian Ocean upper water column), ODP Site 707 (Indian Ocean intermediate waters) and of the Central Mediterranean from Malta (this study & Stille et al., 1996; Mediterranean upper water column) and northern Italy, (Paratethys marginal upper water column). The composite Pacific benthic foraminiferal δ18O record is provided as a measure of sea level change. Line bars note: onset of Western Arabian Sea upwelling,; initiation and intensification of SAM,; initiation of emplacement of evaporites in Iraq and S. Iran and Syria,,; initiation of movement along the Dead Sea Transform; Gomphotherium landbridge, and emplacement of Mediterranean sapropels,.
Figure 3
Figure 3
Modeled ɛNd values in the Mediterranean Sea for different volume inflow values from the Indian Ocean and erosional contributions from alkaline volcanic rocks along the Mesopotamian gateway.
See this image and copyright information in PMC

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