Pleistocene and Holocene

Sea Level Changes
A system called oxygen isotope analysis of deep sea
sediments has enabled scientists to map variations
in sea levels which had major repercussions on the
physical geography of the archipelago. Large areas
of the shallow South China
Sea and Java Sea, (Sunda
Shelf), became periodically
dry land. In fact large river
valleys can
still be
observed on slrbmarine
of the Sunda shelf.
maps
These land bridges did not
extend east
of Wallace’s
- the natural zoogeo-
line
graphical barrier which separates, because of the
depth of the sea, the western part of Indonesia
under Asian influence from the eastern part under
Australian influence. Climate (precipitation and
seasonal patterns) underwent drastic changes
throughout the Quaternary, as did the natural
environment (palaeogeography and vegetation).

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