Control of crystal shape and size on formation of twin lamellae in calcite: Implications for deep burial diagenetic fabrics in limestones
- 68 Downloads
Quantitative data from four shallowly buried and tectonically undisturbed Paleozoic limestones show that twin lamellae develop preferentially in large and irregularly shaped, non-equant crystals. Frequency of lamellae increases with length/width ratio of crystals, and lamellae are more abundant in larger crystals than in small ones. Because burial cements commonly consist of large crystals that fill non-equant remnant voids, these morphologic controls can cause burial cements to undergo preferential twinning. Morphological control on twinning thus causes the seeming paradox of untwinned early cements accompanied by twinned late cements.
Comparison of data from this study of undeformed shallowly buried rocks with data from other limestones shows that frequencies of twinning in undeformed rocks are less than those of tectonically deformed rocks. However, frequencies of lamellae in shallowly buried limestones overlap with those in limestones that have undergone deep burial diagenesis. Thus spacing of lamellae alone is probably not a sufficient criterion by which to recognize deep burial diagenesis.
KeywordsCalcite Burial Ordovician Large Crystal Pennsylvanian
Unable to display preview. Download preview PDF.
- ADLER, F.J., 1987, Mid-Continent Region Correlation Chart: Amer. Assoc. Petrol. Geol. COSUNA Correlation Chart Series.Google Scholar
- FRIEDMAN, M., AND HEARD, H.C., 1974, Principal stress ratios in Cretaceous limestones from Texas Gulf Coast:Amer. Assoc. Petrol. Geol. Bull., v. 58, p. 71–78.Google Scholar
- RAILSBACK, L. B., 1993a, Contrasting styles of chemical compaction in the Upper Pennsylvanian Dennis Formation in the Midcontinent region, U.S.A.:Jour. Sed. Petrology, v. 62, p. 61–72.Google Scholar
- STEARN, C.W., CARROLL R.L., AND CLARK, T.H., 1979, Geological Evolution of North America: New York, John Wiley & Sons, 566 p.Google Scholar
- WENK, H.-R., BARBER, D.J., AND REEDER, R.J., 1983, Microstructures in carbonates. in Reeder, R.J., ed., Carbonates: Mineralogy and Chemistry:Mineral. Soc. Amer. Reviews in Mineralogy, v. 11, p. 301–367.Google Scholar