Abstract

In the Gulf of Carpentaria, northeastern Australia, 30 ka of lacustrine sedimentation provides a record of cyclic deposition of eolian dust (>60 μm) just preceding the Holocene. Adjacent layers containing eolian particles >60 μm in a core from Carpentaria relate to (perhaps intermittent) periods of eolian activity involving sediment deflation, and thus aridity, in northern Australia, each spanning at least 600 yr; major peaks of dust deposition occurred about every 2.25 ka. Such amplitude of cyclicity has already been recognized elsewhere on the globe for other phenomena, including waxing and waning of North American and European mountain glaciers, oxygen-isotope records from Greenland and Antarctic ice cores, changes in deep-sea benthic foraminiferal composition, oxygen-isotope records of deep-sea foraminifera, and atmospheric 14C variations. We propose that the cold Younger Dryas event that affected the Northern Hemisphere is matched by a significant dry event in the tropical region of northern Australia and that the timing of this event fits well into the ∼2.25 ka cyclic pattern described here. Thus, the Younger Dryas is a phenomenon of global significance and is not an "odd" event, contrary to current belief. In addition, we propose that activation of dunes in northeastern Australia, over periods of ∼600 yr, corresponds to, perhaps intermittently, stronger easterly trade winds. During such periods the Intertropical Convergence Zone may not have extended as far south as it does today.

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