Some new apprehensions about change of the level and paleogeography of Caspian Sea in epoch of productive thickness

It was defined that the epoch of productive thickness continued with 5.05 (5.0) to 3.3 million years ago, i.e. it was formed in early Pliocene. The boundary between epoch of the bottom and top departments of this thickness is dated to 4.7 million years ago. It shows that the epoch of the bottom department continued less than 300 thousand years and the top department more than 1 million years. The epoch of the bottom department was an epoch of regress of Caspian Sea when its level has fallen to mark 500 m below modern and the epoch of the top department was an epoch of transgression of the sea. It was defined that during the regressive epoch Caspian Sea consisted of three closed lakes North- Middle- and South Caspian. Paleovolga and Paleoural ran into the North Caspian Lake, Paleoterek and Paleoemba in the Middle-Caspian lake, Paleosamur, the Paleokura and Paleouzboy in the South Caspian lake. Paleosamur flew through the central part of Absheron peninsula. These and other rivers promoted wide development of deltoid adjournment which is very favorable for accumulation of oil and gas deposits. Paleogeography reconstruction has shown that during the epoch of productive thickness in the Caspian region there was a subtropical and damp climate. Then the climatic optimum of Pliocene is marked. Regress has been caused not by roast and an arid climate, and so-called Messene crisis in the result of which Caspian Sea has lost connection with Black Sea. The drain of Volga then was twice less than now and it could not compensate that inflow of water which Caspian Sea received from the Black Sea.