The NSS Bulletin - ISSN 1090-6924
Volume 52 Number 1: 87-94 - December 1990


A publication of the National Speleological Society


Paleomagnetism of Speleothems in Gardner Cave, Washington
Kyle Martin

Abstract

Cores were extracted from a Late Quaternary stalagmite and a flowstone from Gardner Cave, Washington. Dating by 234U/230Th methods give an age range from 20 to 4 Ka.

The stalagmite paleomagnetic record tentatively agrees with paleomagnetic directions previously reported for Fish Lake in southeast Oregon from 12 to 4 Ka. Flowstone paleoinclinations tentatively correlate with the Fish Lake record from 8 to 4 Ka. The flowstone paleodeclinations are shifted 40-80 eastward relative to the Fish Lake record, although the flowstone and cave sediment records show "parallel" declination changes to the west from 5 to 2 Ka. Agreement between the speleothems data and the geocentric dipole field suggests dip-slope bias is not present. A chemical remnant magnetization is inferred. Intensities of magnetization of both speleothems are about 10-3 A/m and 100 times weaker compared with the glacially derived cave sediment.

Agreement exists between the Gardner Cave sediment paleomagnetic record (N = 17, n = 8) and the Fish Lake record but the Gardner Cave record maybe shifted earlier in time relative to Fish Lake. The Gardner Cave sediment record is bracketed by tow corrected 14C dates at 6.7 and 2 Ka, implying mid-Holocene flushing of glacial sediment through the cave.

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