Pedogenesis and early diagenesis of a marine carbonate platform preceding development of a Chesterian transgressive systems tract
- Univ. of Tennessee, Knoxville, TN (United States). Dept. of Geological Sciences
- Tennessee Tech. Univ., Cookeville, TN (United States). Dept. of Geology
A regionally correlative, early Chesterian paleoweathering surface occurs in outcrops of the Monteagle Limestone (ML) and the overlying Hartselle Sandstone (HS) in the Cumberland Plateau region of TN, AL and GA. This surface constitutes a major sequence boundary that developed during a sea-level lowstand when the ML carbonate platform was subaerially exposed and subjected to pedogenesis and meteoric diagenesis. Evidence for pedogenesis of the ML includes reddening and micritization of skeletal allochems, presence of sesquioxidic glaebules and root traces, development of micro-karst pinnacles and fissures, and introduction of abundant vadose silt. The HS rests sharply on the ML with a distinctive scoured to fluted contact, lacking direct evidence for pedogenesis but showing features characteristic of early meteoric diagenesis. Petrographic evidence for subaerial exposure and meteoric diagenesis consists of extensive dissolution and calcitization. Partially dissolved grains are filled with micrite, iron oxides, and clear blocky calcite spar. Intergranular pores are filled with micrite, iron oxides, and clear blocky calcite spar. Intergranular pores are filled with micrite, iron oxides, clay, quartz silt, syntaxial overgrowths (dolomitized) and clear blocky (ferroan) calcite spar. Intergranular micrite, iron oxides, clay and quartz silt are attributed to vadose processes. Clear blocky (ferroan) spar is interpreted as freshwater phreatic. Other features include inclusions of dolomite rhombs in clear blocky calcite spar and zoned dolomite rhombs in the matrix. Under CL, echinoderm grains appear bright orange. Intergranular micrite and clear blocky calcite spar display dull orange luminescence. The dolomitized overgrowths are non-luminescent. Zoning in dolomite rhombs consists of a non-luminescent core with a bright rim. Stable C and O isotope compositions of calcitized grains and intergranular blocky calcite spar are depleted compared to Mississippian marine values.
- OSTI ID:
- 5807796
- Report Number(s):
- CONF-921058-; CODEN: GAAPBC
- Journal Information:
- Geological Society of America, Abstracts with Programs; (United States), Vol. 24:7; Conference: 1992 annual meeting of the Geological Society of America (GSA), Cincinnati, OH (United States), 26-29 Oct 1992; ISSN 0016-7592
- Country of Publication:
- United States
- Language:
- English
Similar Records
Deposition and diagenesis of Flippen Limestone (Wolfcampian), Fisher and Jones Counties, Texas
Deposition and diagenesis of a cratonic Silurian platform reef, Pipe Creek Jr. , Indiana