Reply to "Comment on: 'K-Ar evidence from illitic clays of a Late Devonian age for the 120 km diameter Woodleigh impact structure, Southern Carnarvon Basin, Western Australia"

Uysal, I. T., Golding, S. D., Glikson, A. Y., Mory, A. J., Glikson, M., Iasky, R. P. and Pirajno, F. (2002) Reply to "Comment on: 'K-Ar evidence from illitic clays of a Late Devonian age for the 120 km diameter Woodleigh impact structure, Southern Carnarvon Basin, Western Australia". Earth and Planetary Science Letters, 201 1: 253-260. doi:10.1016/S0012-821X(02)00689-1


Author Uysal, I. T.
Golding, S. D.
Glikson, A. Y.
Mory, A. J.
Glikson, M.
Iasky, R. P.
Pirajno, F.
Title Reply to "Comment on: 'K-Ar evidence from illitic clays of a Late Devonian age for the 120 km diameter Woodleigh impact structure, Southern Carnarvon Basin, Western Australia"
Formatted title
Reply to “Comment on: ‘K–Ar evidence from illitic clays of a Late Devonian age for the 120 km diameter Woodleigh impact structure, Southern Carnarvon Basin, Western Australia”
Journal name Earth and Planetary Science Letters   Check publisher's open access policy
ISSN 0012-821X
1385-013X
Publication date 2002-07-15
Sub-type Editorial
DOI 10.1016/S0012-821X(02)00689-1
Volume 201
Issue 1
Start page 253
End page 260
Total pages 8
Editor E. Bard
E. Boyle
Place of publication Amsterdam, Netherlands
Publisher Elsevier
Collection year 2002
Language eng
Subject CX
260109 Geochronology
780104 Earth sciences
0402 Geochemistry
Formatted abstract
The isotopic and/or stratigraphic age and morphometric analysis of major asteroid/comet impacts are directly relevant to identification of their potential environmental consequences. Renne et al.’s criticisms hinge on the premise that the diameter of Woodleigh is ∼60 km and the impact is of probable pre-Devonian age. Here we clarify the evidence for a Late Devonian age and a diameter of 120 km. We elucidate (A) the methodology and implications of K–Ar analyses of illitic clay minerals; (B) stratigraphic age constraints on the impact event; (C) seismic reflection evidence for a composite fault-bounded central uplift dome, consisting of a 20–25 km wide granitoid plug mantled by a 31–37 km wide updomed sedimentary collar, which widens with depth; (D) morphometric evidence relevant to definition of the outer diameter; and (E) correlations with extinction events.

The impact origin of the 120 km diameter multi-ring geophysical anomaly identified by Iasky and Mory and Mory et al. was confirmed by drilling (GSWA Woodleigh 1), recovering shock metamorphosed granitoid at 171–333 m depth. Stratigraphic constraints indicate a pre-early Jurassic post mid-Devonian age. Rb–Sr biotite, K–Ar biotite, K–Ar feldspar, UV-laser Ar–Ar biotite, feldspar and devitrified glass, apatite fission track, and paleomagnetic pole analyses yielded a range of relic and reset isotopic ages inconsistent with these stratigraphic constraints. However, K–Ar studies of coarser grained illite and mixed layered illite/smectite, separated from the basement core and derived clasts, yielded a concentration of isotopic ages around 359±4 Ma, as well as younger ages, interpreted in terms of intermediate-temperature (200–250°C) hydrothermal activity triggered by the impact event.

The impact interpretation of Mory et al. was questioned by Reimold and Koeberl, who claimed that, should Woodleigh prove to be of impact origin, it is not larger than about 40 km across. However, shock metamorphic features were confirmed by later studies. Bevan and Hough and Hough et al. reiterated the criticism of a 120 km diameter, instead suggesting a 60 km diameter.
© 2002 Elsevier Science B.V. All rights reserved.
Keyword Geochemistry & Geophysics
Mory, A. J. et-al.
Size
Q-Index Code CX
Q-Index Status Provisional Code
Institutional Status UQ
Additional Notes In reply to: Paul R. Renne, W. Uwe Reimold, Christian Koeberl, Rob Hough, Philippe Claeys, Comment on: ``K-Ar evidence from illitic clays of a Late Devonian age for the 120 km diameter Woodleigh impact structure, Southern Carnarvon Basin, Western Australia'', by I.T. Uysal, S.D. Golding, A.Y. Glikson, A.J. Mory and M. Glikson [Earth Planet. Sci. Lett. 192 (2001) 218-289], Earth and Planetary Science Letters, 201 (1), 15 July 2002, 247-252.

 
Versions
Version Filter Type
Citation counts: TR Web of Science Citation Count  Cited 9 times in Thomson Reuters Web of Science Article | Citations
Google Scholar Search Google Scholar
Created: Tue, 14 Aug 2007, 18:00:32 EST