Early-diagenetic sheet-crack cements of Guadalupian shelf, Yates and Tansill Formations, New Mexico - a field and chemical study
Conference
·
· Am. Assoc. Pet. Geol., Bull.; (United States)
OSTI ID:5840117
Tepee-associated sheet-crack structures and carbonate cements that largely fill them are developed in the carbonate facies of the back-reef Capitan Reef complex, Guadalupe Mountains, New Mexico. Sheet cracks, their cements, and associated teepee structures were studied to better understand the timing, nature of precipitating waters, and environment of deposition of the sheet-crack cements. Sheet-crack cements were field classified into 8 morphologic fabrics. Contrary to previous work, this study found that sheet-crack fillings developed symmetrically from roofs and floors. Sheet-crack cements, the sheet cracks, and associated teepee structures developed repeatedly and episodically. Most are erosionally truncated and cross-cut by overlying surfaces. Most cements show isopachous growth indicative of precipitation under phreatic conditions. Some pendant cements suggest precipitation in a vadose environment, indicating occasional exposure of the outer-shelf and shelf-crest facies. Calcite-cement fabrics (39 samples) were analyzed for Sr, Mg, Fe, delta/sup 13/C, and delta/sup 18/O. Chemical compositions range from: Sr = 116 to 5244 ppm; Mg = 215 to 9188 ppm; Fe = 7 to 758 ppm; delta/sup 18/O = -5.6 to +0.4 per thousand; and delta/sup 13/C = +4.9 to 7.5 per thousand (PDB). Sr exhibits distinct groupings of more than 2000 ppm and fewer than 500 ppm. Samples with high Sr are associated with lower delta/sup 13/C, delta/sup 18/O, and Mg compositions. The converse is true for the low Sr values. Isotopically heavier samples are interpreted as precipitated from restricted marine waters. Isotopically lighter samples are interpreted as precipitated from mixed meteoric and marine waters. The meteoric water is inferred to have originated from shelfward, terrestrial source areas. It is hypothesized that these waters traveled through an aquifer system and percolated upward as springs to the sheet-crack area.
- Research Organization:
- Univ. of Wisconsin, Madison
- OSTI ID:
- 5840117
- Report Number(s):
- CONF-850322-
- Conference Information:
- Journal Name: Am. Assoc. Pet. Geol., Bull.; (United States) Journal Volume: 69:2
- Country of Publication:
- United States
- Language:
- English
Similar Records
Interpreting water-rock interaction in ancient carbonates using multi-method microanalysis
Dolomitization of the Madison Group, Wyoming and Utah overthrust belt
Lithologic and diagenetic controls on intergranular porosity of the Ivishak Sandstone, Northstar Unit, Beaufort Sea, Alaska
Conference
·
Tue May 01 00:00:00 EDT 1990
· AAPG Bulletin (American Association of Petroleum Geologists); (USA)
·
OSTI ID:6796800
Dolomitization of the Madison Group, Wyoming and Utah overthrust belt
Journal Article
·
Sat Aug 01 00:00:00 EDT 1987
· AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States)
·
OSTI ID:5753357
Lithologic and diagenetic controls on intergranular porosity of the Ivishak Sandstone, Northstar Unit, Beaufort Sea, Alaska
Conference
·
Sun Dec 31 23:00:00 EST 1995
· AAPG Bulletin
·
OSTI ID:6862133