Saturday, January 8, 2011

A Lost Civilization Beneath the Waters of the Persian Gulf?

From the website comes this fascinating article concerning ancient Middle Eastern history and human culture.

[Image below courtesy of the above-linked article. Click here for an enlarged image of this map.]

From the article:

"Veiled beneath the Persian Gulf, a once-fertile landmass may have supported some of the earliest humans outside Africa some 75,000 to 100,000 years ago, a new review of research suggests.

At its peak, the floodplain now below the Gulf would have been about the size of Great Britain, and then shrank as water began to flood the area. Then, about 8,000 years ago, the land would have been swallowed up by the Indian Ocean, the review scientist said."...

In the article, the flooding of the fertile valley is attributed to rising sea levels following the end of the last major Pleistocene ice age. There is, however, another plausible event that may have contributed to the flooding of this valley - Plate Tectonics.

On the opposite side of the Arabian Plate from the Persian Gulf, lies the Red Sea, which is part of the East African Rift. The activity of the rift is pushing the Arabian Plate to the northeast, where it is colliding with the Eurasian Plate, uplifing the Zagros Mountains of Iran. Where you have the collision of two continental plates, it is common to have the uplift of a linear mountain range, e.g., the Himalayas. Adjacent and parallel to this mountain range is commonly a Foreland Basin, of which the Persian Gulf is an example.

[Image from the What On Earth blog.]

Continuing from the original article:

..."The Gulf Oasis would have been a shallow inland basin exposed from about 75,000 years ago until 8,000 years ago, forming the southern tip of the Fertile Crescent, according to historical sea-level records.

And it would have been an ideal refuge from the harsh deserts surrounding it, with fresh water supplied by the Tigris, Euphrates, Karun and Wadi Baton Rivers, as well as by upwelling springs, Rose said. And during the last ice age when conditions were at their driest, this basin would've been at its largest.

In fact, in recent years, archaeologists have turned up evidence of a wave of human settlements along the shores of the Gulf dating to about 7,500 years ago."...

Aside from the rising sea levels related to the post-Pleistocene ice-cap retreat, is possible that the gradual sinking of this Foreland Basin contributed to the flooding of the area.

Prior to this being a Foreland Basin, it was a part of the ancient Tethys Seaway - a Mesozoic - early Cenozoic seaway between portions of the separating supercontinent Pangea - as partially-described in a World Oil website post. [Scroll down to see Figure 4 and the text above the figure.]

From this World Oil post, in describing the geology behind the 151 giant oilfields in the region:

..."They are concentrated in a large foreland basin formed during the Late Cenozoic collision of the Arabian Peninsula with Eurasia. Downward flexure of the Arabian Peninsula beneath the Zagros Mountains of Iran/Iraq was caused by the northeastward consumption of the Tethys Ocean at the Zagros suture zone. Additional causes of this flexure were the eventual Cretaceous-recent convergence and collision of the Arabian plate against the Eurasian plate. This protracted convergent event has created the Persian Gulf and Mesopotanian [sic] lowlands as a sag in the foreland basin, as well as formation of the Zagros Mountains, with a culmination of fold-thrust deformation in Miocene and Pliocene time."...

It would be fascinating to read a detailed weaving-together of Old Testament Biblical History (and of other ancient texts) with geologically-recent Plate Tectonics events in the Middle East. Including the eruptions of Mt. Etna, Mt. Vesuvius, and the Santorini explosion/tsunami.

Returning to the second-cited source, the What on Earth blog, and the tectonic map, if you notice along the western edge of the Arabian Plate is a transform fault zone, which is the source of the Dead Sea Basin, as a very deep "pull-apart basin" (see the What on Earth January 29, 2009 post, same link).

But that is for another discussion.

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