Rivers Formation Research Articles

A new shelf-to-basin timeline for the Middle Permian (Guadalupian) Capitan Depositional System, West Texas and Southeastern New Mexico, USA

The correlation of the Rader Limestone Member of the Bell Canyon Formation to its shelf equivalent has varied over the years. Some models have equated it with the Seven Rivers Formation, and others to the Yates Formation, or a position straddling both units. More recent workers have used sequence stratigraphic models to refine this shelf-to-basin correlation, placing the “lower” part of the Rader Limestone Member in the Y3 high frequency sequence within the Yates Formation. Despite the presence of bentonites in both the Rader Limestone Member and the Yates Formation, and the potential to add a numerical age datum to the sequence stratigraphic hierarchy, geochemical tephrochronologic techniques have not yet been applied to the deposits. To address these issues, apatite phenocryst trace element chemistry was determined by electron microprobe analysis for samples from three bentonites collected from outcrop localities in Guadalupe Mountains National Park and two from the Gulf PDB-04 research well. Results are interpreted to indicate a correlation between a bentonite 16.5m above the base of the Rader at Back Ridge in the Patterson Hills of Guadalupe Mountains National Park, and one at 1956ft core depth in the PDB-04 core. Careful examination of the gamma-ray log for the well indicates that the 1956ft interval is in the Y3 high frequency sequence of Osleger and Tinker (1999). Further refinement can be made to the third cycle set of this high frequency sequence. Determining whether the bentonite at Back Ridge is in the “lower” or “upper” part of the Rader Member will require additional work. This correlation links the primary reference section for the basal through middle Capitanian Stage being established at Back Ridge with the shelf defined sequence stratigraphic framework. The sample from the Rader is the focus of U-Pb radioisotopic dating (Nicklen et al. in preparation) and would provide the first shelf-to-basin absolute age datum for the Capitan depositional system.

Pecos diamonds-quartz and dolomite crystals from the Seven Rivers Formation outcrops of southeastern New Mexico

Pecos diamonds-quartz and dolomite crystals from the Seven Rivers Formation outcrops of southeastern New Mexico

The sequence stratigraphy, sedimentology, and economic importance of evaporite–carbonate transitions: a review

Abstract World-class hydrocarbon accumulations occur in many ancient evaporite-related basins. Seals and traps of such accumulations are, in many cases, controlled by the stratigraphic distribution of carbonate–evaporite facies transitions. Evaporites may occur in each of the systems tracts within depositional sequences. Thick evaporite successions are best developed during sea level lowstands due to evaporative drawdown. Type 1 lowstand evaporite systems are characterized by thick wedges that fill basin centers, and onlap basin margins. Very thick successions (i.e. saline giants) represent 2nd-order supersequence set (20–50 m.y.) lowstand systems that cap basin fills, and provide the ultimate top seals for the hydrocarbons contained within such basins. Where slope carbonate buildups occur, lowstand evaporites that onlap and overlap these buildups show a lateral facies mosaic directly related to the paleo-relief of the buildups. This facies mosaic, as exemplified in the Silurian of the Michigan basin, ranges from nodular mosaic anhydrite of supratidal sabkha origin deposited over the crests of the buildups, to downslope subaqueous facies of bedded massive/mosaic anhydrite and allochthonous dolomite–anhydrite breccias. Facies transitions near the updip onlap edges of evaporite wedges can provide lateral seals to hydrocarbons. Porous dolomites at the updip edges of lowstand evaporites will trap hydrocarbons where they onlap nonporous platform slope deposits. The Desert Creek Member of the Paradox Formation illustrates this transition. On the margins of the giant Aneth oil field in southeastern Utah, separate downdip oil pools have accumulated where dolomudstones and dolowackestones with microcrystalline porosity onlap the underlying highstand platform slope. Where lowstand carbonate units exist in arid basins, the updip facies change from carbonates to evaporite-rich facies can also provide traps for hydrocarbons. The change from porous dolomites composed of high-energy, shallow water grainstones and packstones to nonporous evaporitic lagoonal dolomite and sabkha anhydrite occurs in the Upper Permian San Andres/Grayburg sequences of the Permian basin. This facies change provides the trap for secondary oil pools on the basinward flanks of fields that are productive from highstand facies identical to the lowstand dolograinstones. Type 2 lowstand systems, like the Smackover Limestone of the Gulf of Mexico, show a similar relationship. Commonly, these evaporite systems are a facies mosaic of salina and sabkha evaporites admixed with wadi siliciclastics. They overlie and seal highstand carbonate platforms containing reservoir facies of shoalwater nonskeletal and skeletal grainstones. Further basinward these evaporites change facies into similar porous platform facies, and contain separate hydrocarbon traps. Transgressions in arid settings over underfilled platforms (e.g. Zechstein (Permian) of Europe; Ferry Lake Anhydrite (Cretaceous), Gulf of Mexico) can result in deposition of alternating cyclic carbonates and evaporites in broad, shallow subaqueous hypersaline environments. Evaporites include bedded and palmate gypsum layers. Mudstones and wackestones are deposited in mesosaline, shallow subtidal to low intertidal environments during periodic flooding of the platform interior. Highstand systems tracts are characterized by thick successions of m-scale, brining upward parasequences in platform interior settings. The Seven Rivers Formation (Guadalupian) of the Permian basin typifies this transition. An intertonguing of carbonate and sulfates is interpreted to occur in a broad, shallow subaqueous hypersaline shelf lagoon behind the main restricting shelf-edge carbonate complex. Underlying paleodepositional highs appear to control the position of the initial facies transition. Periodic flooding of the shelf interior results in widespread carbonate deposition comprised of mesosaline, skeletal-poor peloid dolowackestones/mudstones. Progressive restriction due to active carbonate deposition and/or an environment of net evaporation causes brining upward and deposition of lagoonal gypsum. Condensed sections of organic-rich black lime mudstones occur in basinal areas seaward of the transgressive and highstand carbonate platforms and have sourced significant quantities of hydrocarbons.

Anatomy and origin of toplap in a mixed carbonate‐clastic system, Seven Rivers Formation (Permian, Guadalupian), Guadalupe Mountains, New Mexico, USA

ABSTRACTThe Seven Rivers Formation exposed in Slaughter Canyon, Guadalupe Mountains, New Mexico, reveals complex relations between long‐ and short‐term relative changes in sea‐level, shelf configuration and sedimentation, which interacted to create a distinct toplap geometry. At least five sandstones diverge basinward from a prominent boundary unit marking the surface of toplap at the top of the Seven Rivers Formation and create a series of prograding, shingled clinoforms. The boundary unit is a horizontal, well‐sorted, quartz arenite underlain across the shelf by peritidal carbonate or by other merging sandstones. Preserved palaeotopography is indicated by facies changes downdip and the presence of horizontal geopetal indicators in inclined beds. Near the boundary unit (updip), merging sandstones contain rare sedimentary structures including evaporite moulds and irregular fenestrae and are bounded above and below by peritidal carbonate with microbial laminae, fenestral fabrics and mudcracks. Laterally (downdip), the sandstone‐bounding peritidal carbonate facies pass into subtidal carbonate facies (ooid‐peloid‐fusulinid‐dasyclad‐mollusc pack‐ and grainstone) and interbedded sandstones contain sedimentary structures such as ripple marks and trough to planar cross‐stratification, as well as ooids, fusulinids and other carbonate grains. Toplap is interpreted to have developed by sediment bypass across a subaerially exposed shelf while sedimentation continued in still‐submerged areas downdip from the shelf crest, and hence represents depositional toplap. Physical tracing of subaerial exposure surfaces suggests that the shoreline migrated up and down palaeoslope several times. The vertical component of five short‐term shoreline migrations decreased during formation of the toplap geometry. Sea‐level rose to approximately the same position following each fall to create the toplap geometry. This depositional toplap is the stratigraphic result of high‐‘frequency’ relative changes of sea‐level that combined to produce the larger‐scale geometry. We suggest that changing amplitudes of relative sea‐level may play a significant role in the stratigraphic evolution of platforms and that separating ‘short‐term’and ‘long‐term’relative sea‐level may be ambiguous in such instances.

Structural influences on geomorphic processes and physiographic features, Texas Panhandle: Technical issues in siting a nuclear-waste repository

Research Article| March 01, 1985 Structural influences on geomorphic processes and physiographic features, Texas Panhandle: Technical issues in siting a nuclear-waste repository Thomas C. Gustavson; Thomas C. Gustavson 1Bureau of Economic Geology, University of Texas at Austin, Austin, Texas 78713 Search for other works by this author on: GSW Google Scholar Roy T. Budnik Roy T. Budnik 1Bureau of Economic Geology, University of Texas at Austin, Austin, Texas 78713 Search for other works by this author on: GSW Google Scholar Author and Article Information Thomas C. Gustavson 1Bureau of Economic Geology, University of Texas at Austin, Austin, Texas 78713 Roy T. Budnik 1Bureau of Economic Geology, University of Texas at Austin, Austin, Texas 78713 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1985) 13 (3): 173–176. https://doi.org/10.1130/0091-7613(1985)13<173:SIOGPA>2.0.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Thomas C. Gustavson, Roy T. Budnik; Structural influences on geomorphic processes and physiographic features, Texas Panhandle: Technical issues in siting a nuclear-waste repository. Geology 1985;; 13 (3): 173–176. doi: https://doi.org/10.1130/0091-7613(1985)13<173:SIOGPA>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Deaf Smith County in the Texas Panhandle is being considered by the U.S. Department of Energy as a possible high-level nuclear-waste disposal site. Among the geologic issues being considered are the timing and processes of salt dissolution and related subsidence. Movement along northeast-trending Paleozoic faults in the Texas Panhandle appears to have influenced deposition during the late Paleozoic. Salt of the Upper Permian Seven Rivers Formation appears to have been dissolved preferentially along the same northeast trend. Structural features of post-Seven Rivers strata as well as segments of surface stream valleys overlie and are parallel to the zone of preferential salt dissolution. The association of structure, depositional features, dissolution, and physiographic features, ranging in age from Paleozoic to Neogene, suggests a persistent structural influence. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Petrology of the Carbonate-evaporite Facies Transition of the Seven Rivers Formation (Guadalupian, Permian), Southeast New Mexico

ABSTRACT The Lower Seven Rivers (Guadalupian) evaporite to carbonate facies change, commonly interpreted as a coastal sabkha/carbonate lagoon transition, represents instead an interfingering of dolomite and gypsum in a shallow subaqueous hypersaline shelf setting behind the main Capitan shelf-edge complex. Three mesosaline (35-120) carbonate lithofacies occur in lateral succession over a distance of 3.5 km, adjacent to the evaporites. From the evaporite margin toward the Capitan shelf crest they are: 1) evaporite-edge grapestone grainstones which are current-laminated and occur interbedded with fine-grained quartz sandstone units suggesting a moderate-energy, shallow subaqueous depositional environment; 2) skeletal-rich pellet packstone/wackestones which are commonly current-laminated or burrowed and contain a low-diversity but abundant biota of calcispheres and encrusting forams with a few molluscs and ostracods, suggesting a shallow subaqueous environment; and 3) a shallower shelf facies of pellet wackestone/mudstone characterized by increased micrite, fewer skeletal fragments, and algal stromatolites. The evaporite facies occurs as layers 1 to 7 m thick composed dominantly of mosaic gypsum deposited in a subaqueous environment (i.e., shelf basin) during times of maximum salinity, perhaps influenced partly by the evaporite-margin facies. The mosaic structure is suggested to have been formed by early diagenetic growth of sulfate nodules below the sediment-water interface. The average S34 for this gypsum is +9.3 ± 1.0 which agrees well with the average Upper Permian value of + 10. A fourth carbonate facies of skeletal-poor pellet packstone/wackestones occurs interbedded with the evaporites. It is commonly plana laminated and contains scarce skeletal fragments similar to the skeletal-rich facies. Neither the evaporite facies nor the skeletal-poor facies within it, nor the two adjacent carbonate facies, contain sabkha features such as intertidal algal laminates, desiccation features, or subtidal to supratidal cycles capped by nodular gypsum. Post-depositional diagenesis included 1) cementation of the carbonates by CaCO3 in two forms, including eogenetic isopachous (submarine) cement in the grapestone grainstones and eogenetic/mesogenetic equant spar cement in the grainstones and packstones; 2) eogenetic and probably syndepositional dolomitization of the carbonate rocks to a microcrystalline dolomite; 3) eogenetic insediment growth of evaporite crystals and nodules; 4) post-Permian telogenetic solution brecciation and dedolomitization; and 5) hydration and recrystallization of subsurface anhydrite to gypsum.

Seaward Primary Dip of Fall-in Beds, Lower Seven Rivers Formation (Permian), Guadalupe Mountains, New Mexico: ABSTRACT

Fall-in beds are shelf carbonate rocks which exist adjacent to the Capitan Limestone in a belt about 1 km wide, and which have basinward dips of 5 to 15°. Sedimentologic and structural-geopetal data gathered in field studies of the lower Seven Rivers Formation in North McKittrick Canyon show that tectonic tilting and/or compactional subsidence can account for only part of the basinward dip of fall-in beds, the remainder being primary depositional dip. The dominant lithologies of fall-in beds are stromatolitic algal oncolite rudites and sand-sized, mixed skeletal-peloid grainstones. Rocks are tightly cemented with marine phreatic isopachous fibrous magnesium calcite. Fall-in beds lack features of the adjacent, shallower, but generally submerged shelf-crest facies such as fenestral fabric, pisolites, tepees, erosion surfaces, and shoaling cycles. An inferred energetic, subtidal marine depositional environment for fall-in beds is compatible with their significant basinward depositional dip. Primary geopetal fabrics, although scarce in fall-in beds, have dips not exceeding a few degrees. The dip divergence between bedding planes and geopetal surfaces averages 8 ± 2°, a value which is inferred to be equal to the original depositional dip. Proof of primary seaward dip in fall-in beds lends support to Dunham's marginal-mound hypothesis for the Capitan shelf. Also, primary dip in beds adjacent to the Capitan supports recent interpretations that the Capitan Limestone formed in a relatively deep (30 to 50 m), continually submerged shelf-edge position, and was not a true barrier reef. End_of_Article - Last_Page 471------------

Subaqueous Evaporite Deposition, Permian Shelf, Seven Rivers Formation, Southeast New Mexico: ABSTRACT

Subaqueous Evaporite Deposition, Permian Shelf, Seven Rivers Formation, Southeast New Mexico: ABSTRACT

Geometry and Correlation Along Permian Capitan Escarpment, New Mexico and Texas

Preliminary reexamination of some of the major relations along the Capitan escarpment has revealed several new aspects of stratigraphy and structure. The Queen Formation has been found southeast of Guadalupe Ridge underlying the Seven Rivers Formation and grading into the Capitan reef facies. The Queen is thought also to intergrade with the Goat Seep Dolomite at the head of North McKittrick Canyon. Therefore, either the Capitan southeast of Guadalupe Ridge is Goat Seep or the Queen in McKittrick Canyon lies unconformably on the Goat Seep. Along the lower course of North McKittrick Canyon southeasterly dipping beds overlie the Goat Seep and underlie the Capitan and basal Hegler Member of the Bell Canyon Formation. These may be upper Cherry Canyon Formation equivalents. Field geometric relations of the wedge edge of the uppermost Lamar Member of the Bell Canyon against the structureless Capitan reef suggest an approximate time-depositional equivalence of the top of the Lamar with the top of the Seven Rivers Formation. Faults along the base of the reef escarpment obscure the original relation of the Delaware basin Castile Formation with the reef, but a lower level of Lamar penetration into the reef, as well as a transitional conformity between the Bell Canyon and Castile Formations, suggests that originally the Castile may have been a facies of the upper part of the Capitan and some parts of the Yates-Tansill interval.

Queen Formation (Guadalupian, Permian) Outcrops of Eddy County, New Mexico, and Their Bearing on Recently Proposed Depositional Models: GEOLOGICAL NOTES

The Queen, like several other formations of the Permian basin, contains a widespread quartz sandstone-dolomite unit in its uppermost part. The Shattuck Member is a widespread surface-subsurface marker unit. In the outcrop area investigated, the Shattuck Member of the Queen Formation undergoes facies change up depositional dip into marginal-marine evaporite (gypsum on outcrop, anhydrite in the subsurface) and intertongues south-southeastward with marine carbonate rocks. Prior to development of the Seven Rivers embayment as a topographic feature and before erosion of the upper part of the Queen from the Queen Mesa area, the updip facies change to gypsum is believed to have covered a sizable area, probably at least several hundred square miles. The Shattuck Member at outcrops in the Guadalupe Mountains is largely of marine origin, although it may have passed through an eolian stage prior to deposition in a marginal-marine lagoon. It was not deposited by southward progradation of dune sand updip from, and eventually over, an evaporite environment. Subsurface areas of largely, if not wholly, continental eolian Shattuck probably exist. Origin of a unit as widespread as the Shattuck should not be conceived as the product of one, or even mostly one, environment. The top of the Shattuck is neither an unconformity nor a terminus of the nonmarine phase of a cycle throughout its extent. Rather, this formational contact is a broadly subtle one intertonguing with marine to marginal-marine dolomites and dolomitic limestones of the overlying Seven Rivers Formation. Our evidence shows north-northwestward-sloping depositional topography flanking carbonate-sand barrier islands north of the Goat Seep bank. This slope reversed itself farther north to form the narrow-to-broad lagoon. The current regime was such as to allow quartz- and carbonate-sand transportation parallel with the barriers along the south side of the lagoon. Such a setting would foster quartz sand deposition in facies relation with marine carbonates flanking the islands on the south-southeast and marginal-marine evaporites on the north-northwest. Quartz sand could have reached the lagoon elsewhere along the coast by eolian or deltaic processes, or both.

Lateral Gradation in the Seven Rivers Formation, Rocky Arroyo, Eddy County, New Mexico

Surface exposures in the walls of Rocky Arroyo and adjacent canyons, 12 miles northwest of Carlsbad, New Mexico, reveal an abrupt lateral change in lithology in the Seven Rivers formation. A 275-foot section of gypsum with thin beds of dolomitic limestone merges into a thinner section of uniform dolomitic limestone with some sandstone beds. Evidence is presented to show that this change is the result of interfingering of gypsum and dolomitic limestone rather than of transgressional overlap of limestone on gypsum, as has previously been suggested. The abrupt lateral gradation is thought to have been produced by the close juxtaposition of differing sedimentary environments in Seven Rivers time.

Lateral Gradation in Seven Rivers Formation, Rocky Arroyo, Eddy County, New Mexico: ABSTRACT

The paper embodies results of a study of surface exposures of Rocky Arroyo, 12 miles northwest of Carlsbad, New Mexico. In the walls of this and adjacent canyons is revealed an abrupt lateral change in lithology in the Seven Rivers formation. A 275-foot section of gypsum with thin beds of dolomitic limestone merges into a thinner section of uniform dolomitic limestone with some sandstone beds. Evidence is presented to show that this change is the result of interfingering of gypsum and dolomitic limestone. Thin beds of the latter extend for some distance into the gypsum. However, thick layers of gypsum between beds of dolomitic limestone end abruptly and their places are taken by zones of red porous loosely crystalline calcitic limestone. These limestone beds become thinne away from the gypsum beds and finally pinch out, so that in the final analysis the gypsum beds are equivalent to bedding planes in the section of dolomitic limestone. Channeling of the canyon walls by present-day streams has produced a striking type of breccia, in which angular blocks of dense light-colored dolomitic limestones are firmly embedded in red crystalline highly calcitic limestone. The following conclusions are suggested. The lateral change of section does not represent overlap, as has previously been suggested, but is an abrupt lateral gradation. This gradation is not a local phenomenon but occurs in the Seven Rivers formation for an undetermined distance at the same relative position back of the Capitan Reef, the controlling factor of Permian sedimentation in this region. Advance and retreat of the Seven Rivers seas is suggested, with the anhydrite-depositing environment approaching closest to the Capitan Reef in earliest Seven Rivers time and thereafter making shorter advances. The presence of the lateral gradation in the subsurface should be taken into account when correlating well logs penetrating the Seven Rivers section farther to the east. End_of_Article - Last_Page 935------------