|
|
 |
|||||||||||||||||
|
|||||||||||||||||
 |
|||||||||||||||||
| JOURNAL HOME | HELP | CONTACT PUBLISHER | SUBSCRIBE | ARCHIVE | SEARCH | TABLE OF CONTENTS |
1 Georg-August-Universität, Institut und Museum für Geologie und Paläontologie, Goldschmidtstrasse 3, D-37077 Göttingen, Germany
2 Forschungszentrum Rossendorf, Institut für Radiochemie, P.O. Box 510119, D-01314 Dresden, Germany
Albian carbonate mud-mound limestones exposed near Iraneta, northern Spain, show a fabric- and particle-specific fluorescence. Intense fluorescence is restricted to in situ precipitated microcrystalline (automicritic) fabrics, calcified demosponges, and coralline sponges. Intermediate intensity derives from micritized bioclasts, pellets, and a rim of marine bladed cement. Most invertebrate skeletons, late-diagenetic equant cement, and crosscutting zones of dolomitization are weakly to nonfluorescent. Internal microcrystalline sediment (allomicrite) and red algae debris have variable fluorescence. Correlation between rock fluorescence and soluble humic substances was evaluated from 3 g of automicrite, allomicrite, and cement. Time-resolved laser-induced fluorescence spectroscopy (TRLFS) with ultra-short pulses on two extracrystalline fractions (NaOH-soluble) and two intracrystalline fractions (HCl-soluble and NaOH-soluble) showed that most of the soluble humic substances of automicrite are within the crystals; but conversely, are significantly enriched on outer surfaces of allomicrite. Spar cement is close to detection limits. Fluorescence lifetimes are in the range of 0.5–2 ns and 3.5–6 ns. We conclude that precipitation of automicrite took place during oxidative organic matter diagenesis, i.e., during condensation reactions of degradation products of marine biopolymers. By contrast, allomicrite formed by skeletal breakdown followed by ingestion, organic coating, and reingestion during deposit feeding. A humic-substance–based model of marine polymer gels represents a new approach for the understanding of ancient polygenetic carbonate muds, so typical of Phanerozoic mud-mounds in deeper water settings.
Key Words: micrite • mud-mound • cementation • humic substances • fluorescence
This article has been cited by other articles:
|
|
 |
|
  F. Neuweiler, I. Daoust, P.-A. Bourque, and D. J. Burdige Degradative Calcification of a Modern Siliceous Sponge from the Great Bahama Bank, The Bahamas: A Guide for Interpretation of Ancient Sponge-Bearing Limestones Journal of Sedimentary Research, July 1, 2007; 77(7): 552 - 563. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Desrochers, P.-A. Bourque, and F. Neuweiler Diagenetic Versus Biotic Accretionary Mechanisms of Bryozoan-Sponge Buildups (Lower Silurian, Anticosti Island, Canada) Journal of Sedimentary Research, July 1, 2007; 77(7): 564 - 571. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. Feng, Y. J. Lee, R. J. Reeder, and B. L. Phillips Observation of bicarbonate in calcite by NMR spectroscopy American Mineralogist, May 1, 2006; 91(5-6): 957 - 960. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 F. Neuweiler, V. d'Orazio, A. Immenhauser, G. Geipel, K.-H. Heise, C. Cocozza, and T. M. Miano Fulvic acid-like organic compounds control nucleation of marine calcite under suboxic conditions Geology, August 1, 2003; 31(8): 681 - 684. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Nutritional Modes in Coral--Microbialite Reefs (Jurassic, Oxfordian, Switzerland): Evolution of Trophic Structure as a Response to Environmental Change Palaios, October 1, 2002; 17(5): 449 - 471.
|
|
|
|
 |
|
 P.-A. Bourque, P.-A. Bourque, M. M. Savard, G. Chi, and P. Dansereau Diagenesis and porosity evolution of the Upper Silurian-lowermost Devonian West Point reef limestone, eastern Gaspe Belt, Quebec Appalachians Bulletin of Canadian Petroleum Geology, June 1, 2001; 49(2): 299 - 326. [Abstract] [Full Text] [PDF]
|
|
| JOURNAL HOME | HELP | CONTACT PUBLISHER | SUBSCRIBE | ARCHIVE | SEARCH | TABLE OF CONTENTS |
