Skeletal-Carbonate Neptunian Dikes of the Capitan Reef: Permian, Guadalupe Mountains, Texas, U.S.A.

Diagenetic controls on the isotopic composition of carbonate‐associated sulphate in the Permian Capitan Reef Complex, West Texas

“…The reef facies contains abundant early marine cements (Fig. C), syndepositional brittle fractures and evidence for failure of the shelf margin that suggest unusually high carbonate saturation states for Phanerozoic basins (Babcock & Yurewicz et al., ; Mruk, ; Grotzinger & Knoll, ; Stanton & Pray, ; Rush & Kerans, ; Frost et al., ; Budd et al., ). Given & Lohmann () measured the isotopic compositions of early marine cements in the Capitan Formation; the carbon and oxygen isotopic compositions are reported in δ 13 C and δ 18 O notation as part‐per‐thousand changes in 13 C/ 12 C and 18 O/ 16 O from the Pee Dee Belemnite (PDB) reference standard.…”

Neptunian dykes in the Middle Miocene reefs of western Ukraine: preliminary results

“…We ap ply the def i ni tion given by Playford (1984) for the sed i mentary fill ing of a fis sure that cut the bed ding of the host rock and formed rel a tively soon af ter de po si tion in early-ce mented limestones. Nep tu nian dykes may form due to (1) tec tonic mech anisms that cause rock frac tur ing or ini ti ate grav i ta tional movement or (2) high lo cal depositional re lief and sed i ment in sta bil - A -pol ished slab across the whole fis sure fill in nat u ral po si tion; B, C -mi cro pho to graphs of thin sec tions (see A for lo ca tion); D-G -de tails of the fis sure in fill ing (boxes at C mark po si tions of each mi cro pho to graph): Dnubecularid foraminifer (top) coated with microbialite, E -co lum nar struc ture built by tiny coralline al gal coatings, F -microbialite with clot ted fab rics, G -coralline al gal encrustation em bed ded in microbialite ity that re sults in pas sive grav i ta tional move ment and frac tur ing of the rock (Stanton and Pray, 2004). By ei ther mech a nism, the host rock must be lithified in or der to frac ture and form a sfisure.…”

“…By ei ther mech a nism, the host rock must be lithified in or der to frac ture and form a sfisure. Most nep tu nian dykes oc cur where steep depositional slopes and early lithification fa voured grav i ta tional frac tur ing in clud ing slump ing along an oversteepened depositional mar gin or bend ing and frac tur ing of lithified strata as a re sult of com paction of un der ly ing un con sol i dated sed i ment (Stanton and Pray, 2004). In the case of Medobory, the or thogo nal net work of dykes and par al lel joints strongly sug gest that they are tec toni cally-controlled.…”

The effect of syndepositional deformation within the Upper Permian Capitan Platform on the speleogenesis and geomorphology of the Guadalupe Mountains, New Mexico, USA

“…Until recently, the Type 1 dikes have been widely accepted to have originated as passive fissures formed by rupturing of the brittle Capitan carbonate platform strata subsiding upon the comparatively ductile, deformable, siliciclastic-prone basinal deposits over which the platform had prograded (King, 1948;Horberg, 1949;Newell et al, 1953;Hayes, 1964;Dunham, 1972;Hill, 1987;Melim and Scholle, 1989;Melim, 1991;Hill, 1996;Longley, 1999;Melim and Scholle, 2002;Stanton and Pray, 2004). The age and cause of the early karst associated with these subvertical fissures have been a matter of debate.…”