Tertiary plutons monitor climate change in East Greenland

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doi: 10.1130/0091-7613(1994)022<0775:TPMCCI>2.3.CO;2
Authors:Nevle, Richard J.; Brandriss, Mark E.; Bird, Dennis K.; McWilliams, Michael O.; O'Neil, James R.
Author Affiliations:Primary:
Stanford University, Department of Geological and Environmental Sciences, Stanford, CA, United States
University of Michigan, Ann Arbor, MI, United States
Volume Title:Geology (Boulder)
Source:Geology (Boulder), 22(9), p.775-778. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0091-7613
Publication Date:1994
Note:In English. 32 refs.; illus. incl. sect., 1 table, geol. sketch map
Summary:The δD values of amphibole and biotite in Tertiary plutons in central eastern Greenland decreased by ∼30per mil between 55 and 50 Ma and then increased by ∼35per mil between 50 and 43 Ma. The δD values of amphibole and biotite in the plutons range from -160per mil to -123per mil. These low values reflect isotopic exchange between the igneous rocks and hydrothermal fluids that were dominated by meteoric water. The changes in mineral δD values between 55 and 43 Ma are explained most plausibly by shifts in the isotopic composition of meteoric waters that fed hydrothermal recharge areas. At 50 Ma, uplift related to the Iceland mantle plume elevated hydrothermal recharge areas by 1-2 km. High-altitude, low-δD meteoric waters collected by the uplifted recharge areas caused the ∼30per mil decrease in mineral δD values between 55 and 50 Ma. The subsequent increase in mineral δD values from 50 to 43 Ma corresponds to widening of the North Atlantic Ocean and a change from continental to maritime climate. Thus Tertiary plutons in central eastern Greenland represent a network of paleoclimate stations that monitored the δD of meteoric water during opening of the North Atlantic Ocean basin.
Subjects:Absolute age; Amphibole group; Ar/Ar; Biotite; Cenozoic; Chain silicates; D/H; Dates; Deuterium; Dikes; Gabbros; Granites; Hydrogen; Hydrothermal alteration; Igneous rocks; Intrusions; Isotope ratios; Isotopes; Metasomatism; Meteoric water; Mica group; Paleoclimatology; Paleohydrology; Pegmatite; Plutonic rocks; Plutons; Sheet silicates; Silicates; Stable isotopes; Tertiary; Arctic region; East Greenland; Greenland; Kangerlussuaq; Kap Edvard Holm Complex
Coordinates:N682000 N682000 W0321500 W0321500
Abstract Numbers:95M/3069
Record ID:1994047796
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute.
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