Quick
Search: 		  
advanced search
 GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help 
Geology Signup for GSW Email News
JOURNAL HOME HELP CONTACT PUBLISHER SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
Geology; May 2002; v. 30; no. 5; p. 415-418; DOI: 10.1130/0091-7613(2002)030<0415:ZMIRCA>2.0.CO;2
© 2002 Geological Society of America
This Article
Right arrow Figures Only
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Webb, G. E.
Right arrow Articles by Sorauf, J. E.
Right arrow Search for Related Content
GeoRef
Right arrow GeoRef Citation

Zigzag microstructure in rugose corals: A possible indicator of relative seawater Mg/Ca ratios

Gregory E. Webb*,1 and James E. Sorauf*,2

1 School of Natural Resource Sciences, Queensland University of Technology, GPO Box 2434, Brisbane QLD 4001, Australia
2 Department of Geological Sciences, Binghamton University, Binghamton, New York 13902-6000, USA

Low-Mg calcite (LMC) and high-Mg calcite (HMC) have been identified confidently as original biominerals in different rugose corals. Devonian Tabulophyllum had a LMC skeleton, whereas Pennsylvanian Lophophyllidium had a HMC skeleton. Zigzag microstructure, a diagenetic microstructure in rugose corals, may be related to early migration of Mg2+ ions during transformation of HMC into LMC. Therefore, zigzag microstructure may indicate that the original mineral was HMC even in specimens that subsequently converted to LMC. Stratigraphically, corals with zigzag microstructure are confined to the late Paleozoic, which is coincident with the "aragonite sea" of P.A. Sandberg. Hence, fluctuating Mg/Ca ratios may have directly controlled oscillations in marine carbonate chemistry and the mineral composition of rugose corals so that HMC skeletons (as indicated by zigzag microstructure) formed during intervals with "aragonite seas" and LMC skeletons (e.g., Tabulophyllum) formed during intervals with "calcite seas."

Key Words: seawater • Mg/Ca ratios • rugose coral • microstructure • carbonate diagenesis




This article has been cited by other articles:


Home page
 Journal of PaleontologyHome page
THE ORIGIN AND SIGNIFICANCE OF ZIGZAG MICROSTRUCTURE IN LATE PALEOZOIC LOPHOPHYLLIDIUM (ANTHOZOA, RUGOSA)
Journal of Paleontology, January 1, 2003; 77(1): 16 - 30.


Home page
 Proc. Natl. Acad. Sci. USAHome page
S. M. Stanley, J. B. Ries, and L. A. Hardie
From the Cover: Low-magnesium calcite produced by coralline algae in seawater of Late Cretaceous composition
PNAS, November 26, 2002; 99(24): 15323 - 15326.
[Abstract] [Full Text] [PDF]


JOURNAL HOME HELP CONTACT PUBLISHER SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2009 by Geological Society of America