Geological factors controlling the utility of refractory dolomite: The Cambrian Ledger Formation dolomite, a case study
- Univ. of Missouri, Rolla, MO (United States)
The Middle Cambrian Ledger Formation in eastern Pennsylvania is a high purity, single-stage-sintering dolomite. It yields high quality, direct bonded, environmentally clean, doloma bricks for steel, cement and lime industries use. Geological properties are controlled by the depositional environment, diagenesis, metamorphism, deformation, and rifting. The Middle Cambrian was a time of high sea level stand, high evaporation, low volcanism, and absence of land plants. This produced carbonates low in SiO[sub 2], Al[sub 2]O[sub 3], and Fe[sub 2]O[sub 3] (< 1%). Uniform oolite shoals developed on fault blocks. Early diagenesis dolomitized the [approx]1 mm oolites. The Taconic-Acadian Orogeny greenschist-metamorphism annealed the dolomite by heating it to 300--400 C, at [approx]2 kbar, for [approx]200 million years. This produced a homogeneous coarse crystalline, nonporous, nonplanar dolomite with uniform grain chemistry. Alleghenian overthrusting strained the dolomite, producing deformed oolite ghosts, and minor strain twins. Time, temperature, pressure, and strain increases sinterability and thus suitability of the dolomite for refractory purposes. Near Triassic faults the quality of the brickstone grade dolomite has been degraded to fettling and agricultural grade dolomite. Faulting produced dolomite twinning, polymictic brecciation, and fracture porosity. Karstification generated quartz, feldspar and hematite that filled the porosity. Triassic intrusions partial recrystallized the dolomite incorporating the impurities and thereby degrading it.
- OSTI ID:
- 5011824
- Report Number(s):
- CONF-9303210-; CODEN: GAAPBC
- Journal Information:
- Geological Society of America, Abstracts with Programs; (United States), Vol. 25:3; Conference: 27. annual Geological Society of America (GSA) North-Central Section meeting, Rolla, MO (United States), 29-30 Mar 1993; ISSN 0016-7592
- Country of Publication:
- United States
- Language:
- English
Similar Records
The Mississippian Leadville Limestone Exploration Play, Utah and Colorado-Exploration Techniques and Studies for Independents
Petroleum potential and stratigraphy of Holitna basin, Alaska