Regional cementation associated with unconformity-sourced aquifers and burial fluids, Mississippian Newman Limestone, Kentucky

Aquifer-related cements may be differentiated from deeper burial cements by trace elements, cathodoluminescence, staining, and fluid inclusion analysis in the Mississippian Newman Limestone, eastern Kentucky. Aquifer cements are nonferroan, and show a nonluminescent to dull to nonluminescent to bright cathodoluminescent zonation. They fill leached ooids and fossils indicating waters initially were undersaturated. Early nonluminescent cement (35 ppm Mn, 35 ppm Fe) formed from oxidizing waters in a regional paleoaquifer that became reducing (dull cement; 180 ppm Mn, 565 ppm Fe) but underwent later recharge to form a second nonluminescent cement. Most cementation appears to have been associated with post-Newman unconformities reflecting a shift to a wetter climate in Late Mississippian-Pennsylvanian time which generated regional aquifers. Aquifer cement abundance decreases away from recharge areas and is determined by staining for late burial calcite and then using image analysis to determine the amount of early unstained cement. Later, iron rich burial cements (780 ppm Mn, 4295 ppm Fe) fill remaining pore spaces, compaction-induced fractures, spalled cement rims and tectonic fractures (lined with saddle dolomite and pyrite). Irregular dull/very dull zone patterns relate to preferential concentration of iron along certain crystal faces rather than burial leaching. Secondary fluid inclusions chemically complex brines suggest late stage fluids were (7-17 wt% NaCl) having minimum temperatures of 51 to 156°C, that resided in the formation for such short times that conodont alteration values (consistent with estimated burial temperatures of 38-40°C) were not affected.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Geological Sciences

Department dc:contributor.department

Geological Sciences

Grantor dc:publisher

Virginia Polytechnic Institute and State University

Year dc:date.issued

1984

Author dc:creator

• Niemann, James Cottier

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en_US

Handle dc:identifier.uri

http://hdl.handle.net/10919/76196

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/76196