A Caltech Library Service

Response: Late Permian Extinctions

Knoll, Andrew H. and Bambach, Richard K. and Canfield, Donald and Grotzinger, John P. (1996) Response: Late Permian Extinctions. Science, 274 (5292). pp. 1551-1552. ISSN 0036-8075. doi:10.1126/science.274.5292.1551b.

Full text is not posted in this repository. Consult Related URLs below.

Use this Persistent URL to link to this item:


We agree with Caldeira that the mechanism we proposed (1) to account for large decreases in the C isotopic composition of surface sea water during Neoproterozoic and Permo-Triassic can work only if the negative excursions lasted for less than 10^6 years. It is likely that the Permo-Triassic boundary excursion persisted no longer than the 10^5-year time scale permitted in Kump's model (2). At the proposed Permo- Triassic boundary stratotype at Meishan, China, the stratigraphic interval containing the excursion is 1 meter thick (3); an earlier negative excursion described by Jin (4) from a Capitanian-Wujiapingian boundary section in southwestern China is confined to a comparably thin stratigraphic interval. For the one Neoproterozoic negative excursion closely constrained by radiometric data, uranium-lead zircon dates on volcanic rocks just below and just above the event are the same to within the measurement error of one million years (5).

Item Type:Article
Related URLs:
URLURL TypeDescription
Knoll, Andrew H.0000-0003-1308-8585
Grotzinger, John P.0000-0001-9324-1257
Additional Information:© 1996 American Association for the Advancement of Science. Received 2 October 1996; accepted 1 November 1996.
Issue or Number:5292
Record Number:CaltechAUTHORS:20130204-102912278
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:36753
Deposited By: Tony Diaz
Deposited On:05 Feb 2013 23:24
Last Modified:09 Nov 2021 23:24

Repository Staff Only: item control page