Mesopotamian Seaway Closure c 14 Ma = pongid+sivapith/hominid+dryopith
From Marc Verhaegen@21:1/5 to All on Thu Nov 9 02:01:51 2023
Two-step closure of the Miocene Indian Ocean Gateway to the Mediterranean
Or M Bialik cs 2019 Sci Rep 9, 8842 doi 10.1038/s41598-019-45308-7
The Tethys Ocean was compartmentalized into the Medit.Sea & Indian Ocean early-Miocene,
yet the exact nature & timing of this disconnection are not well understood. Here we present 2 new Neodymium isotope records from isolated carbonate platforms on both sides of the closing sea-way (Malta outcrop sampling & the Maldives IODP Site U1468) to constrain the evolution of past water-mass exchange between the present-day
Medit.Sea & Indian Ocean via the Mesopotamian Seaway.
These data + box modeling results indicate:
water-mass exchange was reduced by ~90% in a first step at c 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 c 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,
- possibly led to a strengthening of S.Asian Monsoon.
1st step = lesser/great ape split c 20 Ma?
2nd step = pongid/hominid split c 14 Ma?