MORPHOLOGY, RELATIONSHIP, AND ORIGIN OF FIBER AND DENDRITE CALCITE CRYSTALS

Authors
Citation
B. Jones et Cf. Kahle, MORPHOLOGY, RELATIONSHIP, AND ORIGIN OF FIBER AND DENDRITE CALCITE CRYSTALS, Journal of sedimentary petrology, 63(6), 1993, pp. 1018-1031
Citations number
111
Language
INGLESE
art.tipo
Review
Categorie Soggetti
Geology
Journal title
ISSN journal
0022-4472
Volume
63
Issue
6
Year of publication
1993
Pages
1018 - 1031
Database
ISI
SICI code
0022-4472(1993)63:6<1018:MRAOOF>2.0.ZU;2-G
Abstract
Fiber and dendrite calcite crystals, formed by abnormal growth conditi ons, are minor but important components of many limestones that have u ndergone vadose meteoric diagenesis. Fiber crystals, which have a leng th:width ratio of greater than 6:1, are divided into hexagonal fibers, rectangular fibers, composite fibers, and rhomb chains according to t heir crystal form. Dendrite crystals are formed of a main stem, primar y branches, and secondary branches. Random and tangential fiber crysta ls refer to masses of fibers that have a random distribution or tangen tially coat a substrate, respectively. Such crystals may be tightly or loosely packed. The shape of fiber and dendrite crystals can be subst antially modified by destructive or constructive diagenetic processes. Destructive modification includes physical breakdown, dissolution, or micritization. Constructive modification, which usually involves epit axial growth around the original fiber or dendrite crystal, may procee d to the point where the original crystals are completely disguised. I n extreme cases fiber crystals can be cemented together to form lattic es that look like dendrite crystals. Fiber and dendrite calcite crysta ls generally form from fluids that are supersaturated with respect to calcium carbonate. Although experimental data suggest that both types of crystal can form from the same parent fluid, there are only rare ex amples where both are present together in nature. Such crystals form t hrough biogenically and abiogenically mediated processes. The common a ssociation of these crystals with plant roots or microorganisms sugges ts that the organisms can produce conditions suitable for growth of th e crystals.