Geoscience Reference
In-Depth Information
12
The pluvial debate
And the parched ground shall become a pool, and the thirsty land
springs of water.
Isaiah 35.7
12.1 Introduction
Flood stories are common to many ancient cultures and are epitomised by the account
given in the Epic of Gilgamesh, written on clay tablets more than 4,000 ago to describe
the life of Gilgamesh, the Sumerian king of the city of Uruk in the lower Euphrates
Valley of Mesopotamia, now modern Iraq (Sandars,
1972
). Excavations at this and
other early Mesopotamian settlements have revealed a sequence of flood deposits and
have shown that towns destroyed by floods were later rebuilt and reoccupied, despite
being located on flood-prone valley floors. The interest of the Epic stems from the
fact that the Sumerians were the first literate inhabitants of Mesopotamia, and their
influence, language and writing persisted for many centuries after the demise of their
dynasty (Sandars,
1972
). It is thus entirely possible that their written account of a
great flood seeped into other literary traditions across the wider region, including the
Old Testament account in Genesis.
At all events, these biblical narratives had a pervasive influence on later geological
thinking, so deposits laid down by melting ice sheets in north-west Europe were often
described as 'diluvial' and were attributed to the biblical flood. Floods and pluvial
events characterised by unusually heavy and prolonged rainfall are thus deeply rooted
in the human psyche. By the time that glacial deposits were recognised for what they
were, thanks in part to the influence of Louis Agassiz (1807-1873) in Europe and
North America, aided by iconoclasts like the vigorous and eccentric Oxford geologist
William Buckland (1784-1856), interest in the Great Flood had begun to wane, at
least among earth scientists. (Buckland was sufficiently passionate in his belated
espousal of the glacial origin of the so-called Drift deposits of central England that
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