The paleoclimatic record provided by eolian deposition in the deep sea; the geologic history of wind

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doi: 10.1029/93RG03257
Author(s): Rea, David K.
Author Affiliation(s): Primary:
University of Michigan, Department of Geological Sciences, Ann Arbor, MI, United States
Volume Title: Reviews of Geophysics
Source: Reviews of Geophysics, 32(2), p.159-195. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 8755-1209 CODEN: RGPSBL
Note: In English. 245 refs.
Summary: The mineral component of pelagic sediment is brought to the deep sea by transport in the wind. Extraction and analysis of this dust allows estimation of the past aridity of the eolian source region, via flux determinations, and of the intensity of the transporting winds, from grain size data. These two parameters, the grain size and mass flux of dust, vary independently. There are three significant sources of modern dust, eastern and central Asia, northwest Africa, and Arabia, all in the northern hemisphere. As the rainfall associated with the Intertropical Convergence Zone is an effective barrier to southerly transport of dust, the northern hemisphere is an order of magnitude more "dusty" than is the southern, an asymmetry that has characterized most of the Cenozoic. Eolian flux data show that most of the northern hemisphere was more arid during glacial maxima, with 3 to 5 times as much dust transported during glacial stages than during interglacials; only northwestern South America varied in the opposite sense. The periodicity of Quaternary variation in both eolian flux and eolian grain size data is strongly influenced by the Milankovitch cycles of orbital variability. Wind intensities vary on a shorter time scale than the general 100-kyr cycles of glaciation and general aridity. Eolian grain sizes display forcing at precessional (19 and 23 kyr), tilt (41 kyr), and at approximately 30 kyr periodicities. As a result the generalization that winds are uniformly stronger during glacial times is not valid. Whole-Cenozoic records show that the largest change in dust flux, an order of magnitude increase, occurred in the northern hemisphere and reflects continental drying associated with the late Pliocene onset of northern hemisphere glaciation. Southern hemisphere eolian records show no sign of paleoclimatic changes in the late Pliocene. The most important change in Cenozoic atmospheric circulation was a severalfold reduction in wind intensity that occurred at the time of the Paleocene-Eocene boundary. Before then, latest Cretaceous and Paleocene winds were essentially as strong as those of the late Cenozoic. This shift appears to be one of several climatic responses to a change in the nature and amount of global heat transport at about 55 Ma. Copyright 1994 by the American Geophysical Union.
Year of Publication: 1994
Research Program: IPOD International Phase of Ocean Drilling
ODP Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Cenozoic; Climate effects; DSDP Site 503; Deep Sea Drilling Project; Deep-sea environment; Deposition; IPOD; Leg 117; Leg 68; Marine environment; Marine sediments; Northern Hemisphere; Ocean Drilling Program; Paleoclimatology; Pelagic environment; Pleistocene; Quaternary; Sediments; Upper Pleistocene; Wind transport
Coordinates: N040303 N040303 W0953813 W0953813
N160748 N182912 E0604438 E0572212
Record ID: 1995021306
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute.