Missourian Stage Research Articles

Vegetational change during the Middle–Late Pennsylvanian transition in western Pangaea

Abstract We present the first analysis of vegetational change in far western equatorial Pangaea (New Mexico, USA) during the Middle–Late Pennsylvanian transition (determined by conodonts and fusulinids) of the Late Paleozoic Ice Age. The study is based on the largest database assembled from this region: 28 of 44 quantitatively analysed floras from 14 of 26 stratigraphic levels. Most sampled floras are ‘mixed’, both below and above the boundary, including both hygromorphic and mesomorphic/xeromorphic taxa. The taxonomic data were recalibrated morphometrically focusing on foliar traits of lamina width and venation. All data were examined using stratigraphic credible intervals, capture–mark–recapture analyses, and resampling analyses. Results indicate no substantive taxonomic turnover across the boundary. This stands in marked contrast to patterns in mid-Pangaean coal basins where there is a large wetland vegetational turnover. However, plant and physical geological data indicate that immediately following the boundary in New Mexico, and for approximately half of the Missourian Stage, floras previously dominated by hygromorphs become overwhelmingly dominated by mesomorphic/xeromorphic taxa. Although expressed differently, the western Pangaean physical and palaeobotanical patterns parallel those from mid-Pangaean coal basins and suggest a widespread environmental change.

Boron proxies record paleosalinity variation in the North American Midcontinent Sea in response to Carboniferous glacio-eustasy

Abstract Salinity variation in ancient epicontinental seas has long been challenging to reconstruct. We determined salinity variation in the Late Pennsylvanian North American Midcontinent Sea based on normalized boron concentrations (B/Ga) and isotopic compositions (δ11B) of bulk shale. We analyzed the Stark Shale Member of the Missourian Stage Dennis Limestone cyclothem in the Charleston core (CC) from the Illinois Basin (eastward, more proximal) and the Iowa Riverton core (IRC) from the Midcontinent Shelf (westward, more distal). Both cores exhibited the same pattern of secular variation, with lower B/Ga and δ11B values at their base and top, recording less saline conditions during lower sea-level stands, and higher values in their middle part, recording more saline conditions at highstands—a pattern that conforms to conventional sequence stratigraphic and glacio-eustatic interpretations of Midcontinent cyclothems. At equivalent stratigraphic levels, B/Ga and δ11B values are systematically lower at CC relative to IRC, reflecting the generally lower salinity conditions of the Illinois Basin relative to the Midcontinent shelf, which is consistent with greater freshwater influence from the east due to heavy river runoff into the Appalachian foreland basin. Our findings serve to demonstrate the utility of paired B concentration and isotope data for paleosalinity analysis of deep-time shale formations.

Dynamic climatic changes during the Late Pennsylvanian icehouse: New insight from high-resolution geochemical records in the Cline Shale, North America

The profound glaciations of the Late Paleozoic represent an extreme climatic perturbation during a time when much of the Earth was initially thought to have been covered with an ice cap for a single prolonged period. Recent research has typically interpreted the Late Paleozoic Ice Age as a dynamic climatic regime characterized by multiple short-term glaciations alternating with globally warmer interglacial conditions within a long-term icehouse epoch. However, the onset and extent of each glaciation interval are not well constrained, especially for the Late Pennsylvanian period. This study presents high-resolution carbon isotopic signatures and other bulk geochemical datasets for deep marine sediments from the Virgilian and Missourian Stages of the Cline Shale (Midland Basin) for the first time. Significant variations in chemical index of alteration (CIA) and chemical index of weathering (CIW) are interpreted as having been caused by climatic oscillations that drove variations in the intensity of chemical weathering on contemporary province areas. The CIA and CIW variation trends suggest a cycle of six cold and dry glacial periods punctuated by six well-defined, relatively warm and humid interglacial periods during the Late Pennsylvanian. In agreement with climate proxies, the coupling variation of the carbon isotope of marine organic matter (δ13Corg) reveals shifts in marine bicarbonate rather than variations of organic matter type. A covariation trend between the carbon isotope signatures of equatorial Russian Platform brachiopods, polar Karoo Basin organic matter, and organic matter in this study indicates a global climate control mechanism was at play, rather than local forcing factors.

Copper isotope evidence of particulate shuttle dynamics in the Late Pennsylvanian North American Midcontinent Sea, with implications for glacio-eustatic magnitude

The North American Midcontinent Sea (NAMS) covered a vast area during Late Pennsylvanian glacio-eustatic highstands, providing a laboratory for analysis of the internal watermass dynamics of large cratonic seas (of which few exist in the Recent). In this study, a novel proxy, copper (Cu) isotopes, was used to gain a better understanding of NAMS watermass dynamics. We analyzed the 63-cm-thick Stark Shale (Dennis Formation, Missourian Stage, Upper Pennsylvanian) in the Iowa Riverton core (IRC) at a centimeter scale in order to reconstruct secular variations in Cu-isotopic compositions (δ65Cu) and other geochemical proxies. The gray shale facies yielded δ65Cu of +0.02 ± 0.06‰ (2σ, n = 14), similar to detrital Cu in modern marine sediments (δ65Cu = +0.08 ± 0.20‰; 2σ, n = 42). In contrast, the black shale facies, in which the proportion of authigenic Cu hosted by the organic fraction is 50–100% of total Cu content, exhibits heavier δ65Cuauth values, mostly between +0.09 and +0.43‰. In modern marine systems, one of the main processes leading to 65Cu-enriched sediment compositions is adsorption of aqueous Cu onto Fe-Mn particulates. The black shale facies of the Stark Shale exhibits four peaks in Mo/U ratios that are indicative of an active particulate shuttle because of the tendency of Mo to adsorb more strongly than U to Fe-Mn particulates. The Sr/Ba ratio, a paleosalinity proxy, shows correlated variations, with high values (indicative of more fully marine conditions) linked to low Mo/U and light δ65Cu, and low values (indicative of brackish conditions) linked to high Mo/U and heavy δ65Cu. These considerations suggest that the flux of isotopically heavy Cu to the sediment–water interface via Fe-Mn cycling was enhanced during brackish intervals, with subsequent reductive dissolution of Fe-Mn particulates allowing transfer of hydrogenous Cu to the organic fraction of the sediment. Control of δ65Cu by Fe-Mn cycling is supported by the results of a sequential extraction experiment showing that organic δ65Cu is positively correlated with Mo/U. These findings provide evidence of large fluctuations in watermass salinity and sea-level elevation within the NAMS at timescales of ∼104 yr during core shale deposition, as previously inferred but not conclusively demonstrated until now. The dynamics of particulate shuttle operation suggest that sea-level fluctuations must have had amplitudes of at least a few tens of meters. These fluctuations ended during the final stages of black shale deposition, probably owing to overall sea-level fall and permanent shallowing of the study site into the oxic, low-salinity surface layer of the NAMS.

Late Pennsylvanian glaciation: Evidence of icehouse conditions from Canyon and cisco units, Midland Basin, Texas

Abstract The late Paleozoic has long been recognized a time of significant continental glaciation associated with high-frequency, high-amplitude glacioeustasy. Although, precise assessment of glacioeustatic amplitudes are difficult to extract from the stratigraphic record, best approximations may be possible by analyzing spatial and temporal distributions of depositional facies utilizing several wells across the study area. We used detailed sedimentologic description and depositional facies analysis from 12 wells and applied rigorous cycle stacking pattern analysis, exposure surfaces recognition and wireline logs to correlate timelines across the wells. On the basis of the high-resolution sequence stratigraphic framework built for the Scurry Area Canyon Reef Operators (SACROC) field, a highly-resolved glacioeustatic curve was generated for latest Desmoinesian to the latest Virgilian. Our eustatic curve suggests that the Missourian and Virgilian stages of the late Pennsylvanian are characterized by high frequency, high-amplitude eustatic fluctuations. The Missourian stage was a period dominated grainstone-capped cycles that are isopachous and conformable. These cycles reflect a eustatic amplitude of at least 37 m with an average duration of 100 ka suggesting the dominance of short-term eccentricity signal. The Virgilian stage is far more complicated and is characterized by highly shingled cycles compared to the Missourian stage. Deeper water phylloid boundstone and calichified shoal complex grainstones are juxtaposed next to each other which suggests a stronger eustatic amplitude (>40 m) compared to the Missourian stage. Although the eustatic amplitude of the Virgilian cycles is similar to those of the Missourian cycles, they have a longer frequency (343 ka) representative of long-term eccentricity. We conclude that the late Pennsylvanian stratigraphy of the SACROC field in the Midland Basin records extensive continental glaciation during the Missourian stage and increased and reached an acme during the Virgilian stage.

Development Of Phylloid-Algal Carbonate Mounds During Regression: Expanding The Build-And-Fill Model

Abstract: The build-and-fill model for mixed carbonate–clastic systems was originally developed to explain thin, widespread, icehouse depositional sequences that maintain more-or-less equal thickness over wide areas despite complex internal architecture that includes both topography-building and topography-filling depositional phases. Lithologic heterogeneity in each small-scale sequence is driven largely by carbonate deposition providing localized relief above surrounding sediment and the eventual infilling of that relief by siliciclastics or a combination of carbonates and siliciclastics. “Phylloid-algal” carbonate mounds are a critical component of these small-scale sequences (cyclothems) during the Late Paleozoic Ice Age (Pennsylvanian–Permian) and have been ascribed to both relief-building and relief-filling phases of build-and-fill, which hinders the use of this model as a predictor of lithofacies distribution and geometry and limits its broader application to other carbonate mound settings. This study includes detailed remapping of Upper Pennsylvanian outcrop and subsurface strata over roughly 3,000 km 2 of northeastern Kansas, which includes the type strata for the Paleozoic example of the original build-and-fill model. The dominant depositional motif for the phylloid-algal lithofacies is that of relief builder with only moderate relief filling as carbonate mounds switched from aggradation to progradation during continued regression. Phylloid-algal lithofacies in the Iola, Wyandotte, Farley, and Plattsburg cyclothems (upper Missourian Stage) were predominantly aggradational and developed mound geometries (relief building) during regression as the base of the photic zone fell to a position low enough to encourage red- and green-algae-dominated, typically micritic bafflestone lithologies to develop on pre-existing topographic highs. As accommodation space continued to decrease, mound development switched from aggradational to progradational before further regression brought nearshore shales into the basin, which filled in bathymetric lows produced between adjacent mounds. The revisions to build-and-fill presented here serve to expand the model and highlight the influence that the dominant relief-building mechanism (frame building/binding vs. baffling), sequence stratigraphic position (transgression vs. falling stage), and interplay between antecedent topography and rate of sea-level rise and fall can have on interpretation of these mixed carbonate–clastic depositional systems. Relief building can occur during both transgression and regression. Relief filling is largely limited to regression. The timing of relief-building within each sequence (TST vs. FSST) is a result of the interplay between the dominant relief-building organisms, basin and/or slope geometry, pre-existing accommodation space (i.e., water depth vs. antecedent topography), and the rates of relative sea-level rise and fall.

Pennsylvanian (Desmoinesian–Virgilian) ammonoid zonation for Midcontinent North America

The most complete, abundant and diverse Middle–Upper Pennsylvanian ammonoid succession in the world occurs in the North American Midcontinent, where more than 40,000 ammonoids representing 52 genera from at least 42 successive stratigraphic levels have been recovered. The Desmoinesian–Virgilian succession comprises a series of seven substage-scale ammonoid genus zones, in ascending order: Wellerites, Eothalassoceras, Pennoceras, Preshumardites, Pseudaktubites, Shumardites and Subperrinites (new), which are subdivided into 14 ammonoid species- or genus-based subzones. The base of the Eothalassoceras Zone is near the current base of the global Kasimovian Stage, the base of the Pennoceras Zone coincides with the base of the regional Missourian Stage (and likely will be close to the base of a revised Kasimovian Stage when its official base is formally selected), the base of the Pseudaktubites stainbrooki Subzone nearly coincides with the base of the regional Virgilian Stage, and the base of the Shumardites Zone coincides with the base of the global Gzhelian Stage, illustrating the value of this zonation for regional and global correlation.

NO MAJOR STRATIGRAPHIC GAP EXISTS NEAR THE MIDDLE-UPPER PENNSYLVANIAN (DESMOINESIAN-MISSOURIAN) BOUNDARY IN NORTH AMERICA

Interregional correlation of the marine zones of major cyclothems between North America and eastern Europe does not support assertions that a major stratigraphic gap exists between the traditional regional Desmoinesian and Missourian stages in North America. Such a gap was previously proposed to explain an abrupt change in megafloral assemblages in the northern Appalachian Basin and by extension across all of North America. Conodont-based correlation from the essentially complete low-shelf Midcontinent succession (distal from the highstand shoreline), through the mid-shelf Illinois Basin, to the high shelf of the Appalachian Basin (proximal to highstand shoreline) demonstrates that all major ,400 kyr cyclothem groupings in the Midcontinent are recognizable in the Illinois Basin. In the Appalachian Basin, however, the grouping at the base of the Missourian is represented only by paleosols and localized coal. The immediately preceding grouping was removed very locally by paleovalley incision, as is evident at the 7–11 Mine, Columbiana County, Ohio, from which the original megafloral data were derived. At the few localities where incised paleodrainage exists, there may be a gap of ,1000 kyr, but a gap of no more than ,600 kyr occurs elsewhere in the Appalachian Basin at that level and its magnitude progressively decreases westward into the Illinois (,300 kyr) and Midcontinent (,200 kyr) Basins. Thus, while a gap is present near the Desmoinesian–Missourian boundary in North America, it is typically more than an order of magnitude smaller than that originally proposed and is similar to the gaps inferred at sequence boundaries between cyclothems at many horizons in the Pennsylvanian of North America.

High-resolution geochemistry and sequence stratigraphy of the Hushpuckney Shale (Swope Formation, eastern Kansas): implications for climato-environmental dynamics of the Late Pennsylvanian Midcontinent Seaway

The Hushpuckney Shale Member of the Swope Formation (Missourian Stage, eastern Kansas) is the core shale of a Kansas-type cyclothem, formed during the late transgressive to early regressive phases of a Late Pennsylvanian glacio-eustatic cycle. Coeval high-frequency climato-environmental dynamics of the Midcontinent Seaway are preserved in the KGS Orville Edmonds No. 1A study core as centimeter-scale variation in major components (organic carbon, authigenic sulfides and phosphate, detrital siliciclastics), organic macerals, trace-element redox proxies (Mo, U, V, Zn), and ichnofabric features. Benthic O 2 levels declined sharply from the base of the black shale (0 cm), went sulfidic at ∼4 cm, and reached a redox minimum at ∼21 cm; above this level, redox potential gradually rose, fluctuating between sulfidic and nonsulfidic conditions from ∼35 cm to the black shale/gray shale contact at 52 cm. Onset of dysoxic conditions at that contact allowed establishment of a benthic community of soft-bodied organisms comprised of deep-tiered tracemakers tolerant of low-O 2 conditions ( Trichichnus), and shallow-tiered tracemakers favoring “soupground” ( Helminthopsis) or “firmground” substrates (the Zoophycos– Phycosiphon– Schaubcylindrichnus– Planolites association). Most geochemical records exhibit a “low-order” cycle spanning the full 52 cm thickness of the black shale submember, reflecting a dominant glacio-eustatic control. The base and top of the black shale submember record lateral migration of the pycnocline across the Midcontinent Shelf during the transgressive and regressive phases, respectively. The maximum flooding surface (MFS) is at ∼17–23 cm, an interval containing the euxinic peak and characterized by high concentrations of illite (representing a cratonic siliciclastic flux) and terrestrial organic macerals, the product of transient increases in humidity, weathering rates, and the export of coal-swamp vegetation associated with the interglacial highstand of the Swope cyclothem. Although a transgressive “surface of maximum starvation” (SMS) cannot be confidently identified, a phosphate-rich “regressive condensation surface” at ∼28–34 cm records pycnoclinal weakening due to increased aridity associated with renewed southern hemisphere icesheet growth; a correlative shift in dominance from terrestrial- to marine-derived organic macerals reflects increased upwelling of nutrient-rich deepwaters and enhanced primary productivity. Penecontemporaneous paleogeographic and -climatic factors (e.g., semirestricted circulation, monsoonal precipitation) predisposed the Midcontinent Seaway toward sensitivity to high-frequency climato-environmental fluctuations, which are preserved as 2- to 7-cm-thick cycles in the study core. The 52-cm-thick black shale submember contains ∼12 such “high-order” cycles, which have an estimated average duration of ∼2 to 9 kyr, implying a sub-Milankovitch-band (i.e., millennial scale) climatic control. The results of this study are relevant to the sequence stratigraphic interpretation of Kansas-type cyclothems, the dynamics of Gondwanan Ice Age glacio-eustatic cycles, and the development of boundary conditions for Late Pennsylvanian paleoclimate models.

Abstract: Regional Stratigraphic Analysis of A Pennsylvanian Carbonate Shelf and Margin in Kansas

Abstract Gamma-ray logs representing Upper Pennsylvanian strata were correlated using computer-assisted techniques for distances of 220 mi (354 km) along a northwest-to-southeast line of section in western and south-central Kansas. The section crosses a carbonate-dominated shelf of the Virgilian and Missourian Stages that borders the Anadarko Basin. Correlations were based on log data sampled at 0.5-ft (15-cm) intervals. Manual correlation of cyclothemic-scale genetic units approximately 50 ft (15 m) in thickness provided initial constraints to the automated correlation using regionally extensive marine shales (maximum flooding surfaces and condensed sections). These marine-shale markers were correlated previously from a regional study of core, outcrops, and wireline logs. Correlations of natural gamma-ray response within these genetic units were derived using computer-assisted autocorrelation. Stratal units resolved include: (1) cyclothemic-scale genetic units (10's of meters in thickness); (2) longer term sets of cyclothemic-scale genetic units (10's to 100's of meters in thickness); and (3) meter-scale strata] elements including high-frequency cycles within genetic units. Classic onlap and offlap and forward- and backward-stepping stratal geometries are noted. Reliability of correlations was computed. Uncorrelated intervals result in triangular-shaped intervals of no correlation between wells. These are associated with onlap and offlap geometries. This is critical evidence to assess stratigraphic truncations, usually limited in manual correlation unless surfaces are described in core or outcrop or seen in seismic data. Regional correlation of genetic units and coherent sets of genetic stratigraphic units strongly suggest important allogenic and basin controls on sedimentation. This computer-assisted method provides an opportunity to assist in development of consistent, finer scale correlations that augment traditional geologic analyses. Manual correlation of high-resolution genetic units using wireline logs has been limited by issues of consistency and subjectiveness. Computer-assisted correlation can minimize these issues, if properly calibrated (trained). Integration of manual and computer techniques will help place surface and subsurface studies on a more equal footing to help resolve controls on sedimentation. Targeting stratigraphic traps is facilitated using digital well logs and computer techniques. Reservoir attributes including porosity and resistivity and computed variables such as bulk volume water, fluid saturations, and even hydrocarbon pay can be introduced into the correlated sections. Furthermore, false-color imaging of the petrophysical properties and computed information within the digital cross sections will help identify anomalies and potential drilling opportunities.

Geology of the Merriam Limestone (Upper Pennsylvanian) at Merriam, Kansas

The Merriam Limestone Member of the Plattsburg Limestone (Lansing Group, Missourian Stage, Upper Pennsylvanian) is named for Merriam, Johnson County, Kansas. It is well exposed in the many new road cuts in and around the village (now the city) of Merriam. The type section has been obliterated by industrialization of the area, and a reference section also has been demolished by recent interstate highway construction. Therefore, another reference section at the intersection of 135 and US56 is designated in this paper. The Merriam Limestone Member of the Plattsburg Limestone is the lowest unit in the Lansing Group (Missourian Stage, Upper Pennsylvanian). It is unconformably underlain by the Bonner Springs Shale of the Kansas City Group and conformably overlain by the Hickory Creek Shale Member of the Plattsburg Limestone. The Merriam Limestone is surprisingly uniform over a large area both in composition and thickness. Usually it is a thin, hard, dense, blocky, fossiliferous limestone about 2-ft. thick. The unit was named by Norman D. Newell in 1933 when he was working on the Missourian rocks for his Ph.D. dissertation in this part of the state. He designated the type section in a quarry in the NWc of sec. 7, T. 12 S., R. 25 E. in the village of Merriam, Johnson County, Kansas. The Merriam Limestone is one of the many thin, widespread transgressive limestone units that occur in the cyclic sequence of alternating limestone, shale, and sandstone which constitute much of the Upper Pennsylvanian of the Midcontinent. These units are particularly well exposed in east-central Kansas extending from the Kansas (Kaw) River to the Oklahoma border. The sequence was made famous by R. C. Moore and his coworkers in the 1930's, 1940's, and 1950's.

Ultrastructural studies of pteridosperm pollen: Nanoxanthiopollenites clendening and nygreen

The ultrastructure and organization of the Upper Pennsylvania (Missourian Stage) taxon Nanoxanthiopollenites mcmurrayii Clendening and Nygreen is described. The exine is ornamented by widely spaced spines that possess the same infrastructure as the remainder of the exine. Ornamentation between the spines is foveolate. The exine consists of a thin nexine and alveolate sexine infrastructure similar to that described in the seed fern pollen types Monoletes and Parasporites.

Nanoxanthiopollenites, anew monolete miospore from the upper pennsylvanian of Kansas

Abstract Nanoxanthiopollenites mcmurrayi gen. et sp. nov. is described from the Bonner Springs Shale, Zarah Subgroup, Kansas City Group, Missourian Stage, Upper Pennsylvanian Series of Johnson County, Kansas. The new spore genus is monolete, with the suture being somewhat sigmoid in direction; sculpturing of the exine surface consists of conspicuous spinae. The general morphological features indicate a possible relationship to the Medullosaceae.

Foraminiferal Ooze in the Coalmeasures of Iowa

Previous articleNext article FreeForaminiferal Ooze in the Coalmeasures of IowaJ. A. UddenJ. A. Udden Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Journal of Geology Volume 11, Number 3Apr. - May, 1903 Article DOIhttps://doi.org/10.1086/621076 Views: 22Total views on this site PDF download Crossref reports no articles citing this article.