Basal Pennsylvanian Research Articles

Lower Permian (Late Kungurian) conodonts from the Sibumasu Terrane, Malaysia: paleoecological, paleobiogeographical and tectonic implications

AbstractLate Kungurian (Lower Permian) conodonts are described from the Kanthan Limestone, Perak, Peninsular Malaysia and for the first time from the Sibumasu Terrane of the Malay Peninsula. The co-occurrence of Gullodus duani, Gullodus hemicircularis, Gullodus sicilianus, Mesogondolella lamberti and Mesogondolella siciliensis represent the Mesogondolella lamberti International Conodont Zone and the broadly equivalent Mesogondolella siciliensis Regional Conodont Zone. A small fault-bounded basal Pennsylvanian (basal Bashkirian) conodont fauna including Gnathodus girtyi simplex and Declinognathodus inaequalis is also reported. The late Kungurian conodonts from the Kanthan Limestone were deposited in a relatively deep-water environment on the northern passive margin of the Sibumasu Terrane of the eastern Cimmerian Continent located at c. 35oS latitude. Biogeographically, the fauna represents the southern peri-Gondwana Cool Water Province which is consistent with its palaeogeographic location. A new scheme, utilizing characteristics of P1 elements, including position of the 1st denticle, location of 2nd and 3rd denticles, platform shape, platform cross-section, denticle shape in cross-section, and lateral denticle development is proposed for distinguishing between species of the hindeodid genera Gullodus, Hindeodus and Isarcicella. The late Kungurian fauna from the Kanthan Limestone represents the southern peri-Gondwana Cool Water Province supporting palaeogeographic reconstructions placing the Sibumasu Terrane in moderate southern palaeolatitudes in the Kungurian.

Early Carboniferous (Mississippian) intertwining sediment dispersal network across the Laurentian cratonic interior

Early Carboniferous (Mississippian) strata across the Laurentian cratonic interior record the transition from a stable carbonate platform, supporting a broad epicontinental sea, to a series of widespread, mixed carbonate-siliciclastic successions. As the southern terminal sink, the Mississippian succession preserved on the southern Midcontinent provides evidence and constraints for sediment dispersal patterns. This paper presents the first comprehensive U–Pb detrital-zircon geochronological record of all known Mississippian sandstones from the southern Ozark Dome of southern Missouri and northwestern Arkansas. This study identifies the provenance of these Mississippian sandstones and establishes their sediment dispersal networks across the cratonic interior. Results show that a major provenance shift occurred between Lower and Upper Mississippian strata. The Lower Mississippian Bachelor Sandstone was sourced from the Laurentian craton, while Upper Mississippian and basal Pennsylvanian sandstones were sourced through recycling of upper Proterozoic and lower Paleozoic sandstones within the Laurentian craton to the north, the unroofing of the Appalachian orogenic belt from the east-northeast, and potentially some direct contribution from uplifted Precambrian basement along the Transcontinental Arch to the northwest. By combining previously published detrital zircon data from Laurentia, we propose that the Mississippian sedimentation reflects an intertwining dispersal system associated with multiple sources. Sediments derived from all three potential sources were merged and transported southward across Laurentia.

Carboniferous Manning Canyon Formation, northern Utah, USA: A carbonate-mud-dominated cyclothem motif recording the main onset of the late Paleozoic Ice Age

A poorly understood Mississippian to basal Pennsylvanian succession is preserved in parts of northern Utah, western USA. The mudrock- and carbonate-dominated Manning Canyon Formation and lateral equivalents have been referred to as “cyclothems” and might therefore be expected to preserve a record of repeated, late Paleozoic sea-level excursions similar to cyclothemic successions elsewhere in the paleotropics. In this paper, we document the sedimentology and stratigraphy of the Serpukhovian to earliest Bashkirian Manning Canyon Formation, focusing on surface exposures in the Oquirrh and Uinta Mountains and a cored subsurface intersection from central Utah. Four facies associations were identified in the Manning Canyon Formation: Mid-Shelf, Muddy Inner Shelf, Deltaic, and Coastal Plain, which are herein interpreted in the context of a muddy, semi-enclosed, epicontinental carbonate shelf fringed by a low-relief coastal plain. These facies associations are broadly comparable to recent and extant environments from a range of equatorial, clay-rich, deltaic, coastal plain, and offshore carbonate-producing environments in the Caribbean Sea, northern Australia, and SE Asia, which can be used as first-order analogues for the Manning Canyon Formation. These modern analogues suggest that several relative sea-level excursions of <40 m are recorded in the unit. The stratigraphically oldest records of substantial relative sea-level oscillations are in the lowermost Manning Canyon Formation. These preceded a more sustained pattern recorded by at least nine 4th-order, high-frequency and high-magnitude (≥40 m) sea-level cycles that characterize the upper two-thirds of the formation. Sea-level highstands are recorded by open marine shelf facies, whereas lowstands are recorded by incised channel and valley fills, and (presumed) laterally equivalent paleosols and thin coals. No record of high frequency/high magnitude relative sea-level oscillations comparable in character to those preserved in the Manning Canyon Formation was documented in the underlying stratigraphy. It is concluded that the Manning Canyon Formation may record the main onset of the eustatic signal associated with the main phase of the late Paleozoic Ice Age at ~330 Ma.

Detrital zircons and sediment dispersal in the eastern Midcontinent of North America

Abstract Results of detrital-zircon analyses (U-Pb ages and initial Hf values, εHft) of Mississippian–Pennsylvanian sandstones in the Michigan, Illinois, and Forest City basins are remarkably similar to data for coeval sandstones in the Appalachian basin, indicating dispersal of sediment from the Appalachian orogen through the Appalachian basin to the eastern Midcontinent during the late Paleozoic. The similarities of results include matches of the two most prominent age groups (1300–950 Ma and 490–350 Ma), as well as matches of the less abundant age groups. Comparisons of the data are from observations of probability density plots and multidimensional scaling of U-Pb age data and of εHft values. Despite the dominance of an Appalachian signature in all samples, some samples contain grains with ages that suggest intermittent additional sources. Four samples (three ranging in depositional age from Morrowan to Atokan–Desmoinesian in the Illinois basin, and one of Desmoinesian age in the Forest City basin), in addition to typical Appalachian age distributions, have prominent age modes between 768 and 525 Ma, corresponding in age to Pan-African/Brasiliano rocks in Gondwanan accreted terranes in the Appalachian orogen, suggesting intermittent dispersal from the Moretown terrane of the northern Appalachians. Sandstones in the Appalachian basin and those in the Midcontinent basins have very few grains with ages that correspond to the Alleghanian orogeny in the Appalachian orogen. Nevertheless, three sandstones each in the Illinois basin and Forest City basin with depositional ages of 312–308 Ma have a few zircon grains in the age range of 321 ± 5 to 307 ± 4 Ma. The nearly identical crystallization and depositional ages suggest reworking at the depositional sites of air-fall volcanic ash from the Alleghanian orogen, rather than fluvial transport from the orogen. The basal Pennsylvanian sandstones lap onto a regional unconformity around the northern rims of the Illinois and Forest City basins, suggesting sources for recycled grains. Along the northern edge of the Illinois basin, Ordovician sandstones beneath the unconformity may have contributed minor concentrations of Superior-age zircons in the basal Pennsylvanian sandstones. Basal Pennsylvanian sandstones in the Forest City basin lap onto Mississippian strata, suggesting possible recycling of zircons from eroded Mississippian sandstones.

Magnetic polarity stratigraphy and palynostratigraphy of the Mississippian-Pennsylvanian boundary interval in eastern North America and the age of the beginning of the Kiaman

Magnetic polarity data from the Maritimes Basin in eastern Canada reveal patterns of magnetic reversal through ∼17 m.y. of late Mississippian and early Pennsylvanian time. We collected samples from three sections on Cape Breton Island, a fourth that extends a section studied previously, and a fifth from a deep cored well on Prince Edward Island. We compared the polarity data from these sections to previous results from lower parts of the Joggins section of eastern Canada. All sections are constrained by new palynological data and collectively span the late Mississippian, Brigantian, Pendleian, and much of the Arnsbergian substages. A major unconformity at the Pennsylvanian-Mississippian boundary makes correlation difficult. The late Mississippian Arnsbergian substage is dominated by normal polarity, whereas the Pendleian and Brigantian are characterized by normal and reversed polarity intervals in about equal proportions. In the United States, the Mississippian-Pennsylvanian boundary is a major hiatus that juxtaposes strata of early Pennsylvanian age on Mississippian strata ranging in age from Brigantian to mid- to late Arnsbergian. Data for the Mauch Chunk Formation in the United States provide polarity reversal patterns for correlative sequences in the Central Appalachian Basin. Field mapping and magnetic polarity data show closely comparable Mississippian-Pennsylvanian relationships in the Maritimes Basin more than 1500 km northeast from the U.S. sections. The eustatic event that coincides with the Mississippian-Pennsylvanian boundary unconformity is late Arnsbergian to Yeadonian in both the central Appalachians and Maritime Basins. Basal Pennsylvanian strata of Yeadonian to Langsettian age on Cape Breton Island reveal normal paleomagnetic polarity through several hundred meters of section. These strata are overlain by a thick section showing only reversed polarity. We believe that this polarity boundary is the base of the Kiaman. An early Langsettian position (ca. 318 Ma) for the base-Kiaman superchron is indicated by these new data. In eastern Nova Scotia and New Brunswick, the sedimentary rocks just above the unconformity are of reversed polarity. It is clear that the sedimentation in the two areas is affected by the unconformity, and no magnetic or palynological correlation is possible. Above the unconformity, only saetosa zone sediments are present.

Discussion on ecology of earliest reptiles inferred from basal Pennsylvanian trackways Journal , Vol. 164, 2007, 1113–1118

David Keighley, John Calder, Adrian Park, Ronald Pickerill & John Waldron write: In a recent article, Falcon-Lang et al . (2007, p. 1113) claim ‘trackways representing the earliest evidence for the origin of reptiles (amniotes) are reported from the basal Pennsylvanian Grande Anse Formation, New Brunswick’. We note inaccuracies in the paper and bring attention to various lines of evidence, any one of which casts serious doubt on their claim. ### Age of the Grande Anse Formation. Falcon-Lang et al . (2007, p. 1113) report a location at Shepody Bay, ‘on the eastern side of the Maringouin Peninsula, New Brunswick’ (actually located on the western side, Fig. 1) that preserves interface sedimentary structures that they interpret as amniote trackways. The authors infer an earliest Langsettian (earliest Westphalian), or possibly latest Namurian, age for the Grande Anse ‘Formation’ at this locality (the unit is not formally defined). This interpreted age of the strata was based on two lines of evidence: (1) a palynological age determination from an unpublished report; (2) its reported stratigraphic position equivalent to the Little River Formation of Nova Scotia, conformably overlying the Boss Point Formation. Fig. 1. Map of the Maringouin peninsula and nearby Joggins area, New Brunswick and Nova Scotia, incorporating elements of Gussow (1953), Ryan et al . (1990), St. Peter & Johnson (1997) and Calder et al . (2005). (1) The report cited by Falcon-Lang et al . (2007) actually states that the spores indicate an age ‘no older than the early middle Langsettian’ (Dolby 1999, p. 43). Therefore, the Grande Anse Formation would not be of identical biostratigraphic age to that reported for the Little River Formation, which is of probable late Namurian to basal Westphalian (basal Langsettian) age (Calder et al . 2005). Regardless, Upper Palaeozoic strata in eastern Canada (Fig. 2) lack many of the stratigraphically diagnostic marine index fossils and European miospores recorded in the literature (Calder 1998; Utting et al . 2005) and so it is not currently possible to unequivocally constrain the age of the Grande Anse strata. In addition, recent recognition of rapid Mississippian stratigraphic inversions in SE New Brunswick (e.g. Park & St. Peter 2005) has supported interpretations that at least some spore assemblages in the region are entirely reworked (e.g. Dolby 2004). Fig. 2. Summary of mid-upper Carboniferous stratigraphy for the Maritime Provinces. For brevity and clarity, only formation and group names from this discussion have been included. Data are a compromise of numerous sources and so, although the stratigraphic …

Ecology of earliest reptiles inferred from basal Pennsylvanian trackways

Trackways representing the earliest evidence for the origin of reptiles (amniotes) are reported from the basal Pennsylvanian Grande Anse Formation, New Brunswick, Canada. Amniote characters include pentadactyl manus and pes, slender digits whose relative lengths approximate a phalangeal formula of 23453 (manus) and 23454 (pes), narrow digit splay (40–63°), putative transverse scale impressions on digit pads, and straight tail drag. The trackways occur in the deposits of a seasonally active dryland river channel. Sedimentological context suggests, for the first time, that early amniotes existed in water-stressed environments, where the cleidoic egg would have presumably conferred reproductive advantage.

Low-accommodation detrital apron alongside a basement uplift, Pennsylvanian of Midcontinent North America

The northern end of the 650-km-long Nemaha Uplift (Nebraska and Kansas, USA) is an important example of basin-margin sedimentation in the North American Midcontinent. An apron of coarse, basal Pennsylvanian arkosic clastic sediments (BPC) was deposited on the flanks of the uplift while marine cyclothems were encroaching from the east. Small-scale fining-upward intervals, many with demonstrably erosional bases, dominate the BPC and are interpreted as overridingly fluvial in origin. Weak paleosols, desiccation cracks, and reddened intervals in the BPC record episodic subaerial exposure. Multiple, burrowed horizons and heterolithic strata of probable tidal origin and rare marine fossils also indicate episodic marine influence. The BPC appear to have been deposited as a thin apron of coalesced, alluvial fans and fan deltas. Deposition of the BPC occurred during the waning of uplift and subsequent quiescence. The comparative thinness and large-scale packaging of the BPC are compatible with the controlling effects of relict relief, regional subsidence, and eustasy, rather than ongoing, major vertical displacements along active faults. A strong autocyclic influence on sedimentation is evidenced by stacked fining-upward intervals of poorly-sorted conglomerates, sandstones, and sandy mudstones. Correlations demonstrate that the accumulation of the BPC took place over more than seven major sea-level cycles, beginning in Cherokee Group times (middle Moscovian/middle Pennsylvanian) and ending only when the eroded uplift was inundated and buried by marine cyclothems. On the basis of local correlations with marine cyclothems, and using black phosphatic shales (so-called “core shales” of Heckel, P.H., 1986. Sea-level surve for Pennsylvanian eustatic marine transgressive-regressive depositional cycles along Midcontinent outcrop belt, North America: Geology 14, 330-334., Heckel, P.H., 1994. Evaluation of evidence for glacio-eustatic control over marine Pennsylvanian cyclothems in North America and correlation of possible tectonic effects. In: Dennison, J.M., Ettensohn, F.R. (Eds.), Tectonic and Eustatic Controls on Sedimentary Cycles, SEPM Concepts in Sedimentology and Paleontology No. 4, pp. 5-87) as marker beds, we speculate that the BPC exist in backstepping sequences and/or parasequences alongside the flanks of the Nemaha Uplift. The BPC are lithologically comparable to contemporaneous deposits alongside the Ancestral Rockies, Amarillo–Wichita Uplift, and other buried basement highs in North America. Nonetheless, the BPC are an order of magnitude thinner, are dominantly retrogradational, rather than progradational, and their occurrence was not associated with major displacements along basin-bounding faults. In this manner, the BPC are a useful example of low-accommodation, eustasy-dominated, coarse-grained terrigenous clastic deposition around an uplifted basement block.

Characterization of the Mississippian chat in south-central Kansas

To understand production from low resistivity-high porosity Mississippian chat reservoirs in south-central Kansas it is necessary to understand the nature of deposition and diagenesis, how tectonics is a factor, the lithofacies controls on petrophysical properties, and log response to these properties. The initial mudstones to sponge-spicule wacke-packstones were deposited in transgressive-regressive (T-R) cycles on a shelf to shelf margin setting, resulting in a series of shallowing-upward cycles. Sponge-spicule content appears to increase upward with increasing cycle thickness. After early silicification, inter- and post-Mississippian subaerial exposure resulted in further diagenesis, including sponge-spicule dissolution, vuggy porosity development in moldic-rich rocks, and autobrecciation. Meteoric water infiltration is limited in depth below the exposure surface and in distance downdip into unaltered, cherty Cowley Formation facies. Areas of thicker preserved chat and increased diagenesis can be correlated with structural lineaments and, in some areas, with recurrent basement block movement. Combination of folding or block fault movement prior to or during development of the basal Pennsylvanian unconformity, sponge-spicule concentration, and possibly thickness of overlying bioclastic wacke-grainstones resulted in variable reservoir properties and the creation of pods of production separated by nonproductive cherty dolomite mudstones. These events also resulted in alteration of the depositional cycles to produce a series of lithofacies that exhibit unique petrophysical properties. From bottom to top in a complete cycle seven lithofacies are present: (1) argillaceous dolomite mudstone, (2) argillaceous dolomite mudstone that has chert nodules, (3) clean dolomite mudstone that has nodular chert, (4) nodular to bedded chert, (5) autoclastic chert, (6) autoclastic chert that has clay infill, and (7) bioclastic wacke-grainstone. The uppermost cycle was terminated by another lithofacies, a chert conglomerate of Mississippian and/or Pennsylvanian age. The chert facies exhibit porosities ranging from 25 to 50% and permeabilities greater than 5 md. The (Begin page 86) cherty dolomite mudstones, argillaceous dolomite mudstones, and bioclastic wacke-grainstones exhibit nonreservoir properties. Reservoir production, numerical simulation, and whole core data indicate fracturing can be present in chat reservoirs and can enhance permeability by as much as an order of magnitude. Capillary pressure data indicate the presence of microporosity and can explain high water saturations and low resistivity observed in wire-line logs. Relative permeabilities to oil decrease rapidly for saturations greater than 60% and may be influenced by dual pore systems. Archie cementation exponents increase from 1.8 for mudstones to more than 2.5 in the cherts that have increasing sponge-spicule mold and vug content. Detailed modified Pickett plot analysis of logs reveals critical aspects of chat character and can provide reliable indices of reservoir properties and pay delineation. Models developed provide additional insight into the chat of south-central Kansas and understanding of the nature of controls on shallow-shelf chert reservoir properties.

Abstract: Outcrop and Subsurface Evaluation of Chesterian and Basal Pennsylvanian Sequences in Western Kentucky&amp;nbsp;

Abstract: Outcrop and Subsurface Evaluation of Chesterian and Basal Pennsylvanian Sequences in Western Kentucky&amp;nbsp;

Abstract: Petrographic Differentiation of Basal Pennsylvanian and Mississippian (Chesterian) Siliciclastics in Western Kentucky

Abstract: Petrographic Differentiation of Basal Pennsylvanian and Mississippian (Chesterian) Siliciclastics in Western Kentucky

Palynology of the upper Pennsylvanian Dalton coal, Palo Pinto county, texas, U.S.A.

Abstract The Dalton Coal of north‐central Texas yields a palynomorph assemblage characteristic of basal Late Pennsylvanian (Stephanian) coals from the Midcontinent U.S.A., and also indicative of an allochthonous origin for the greater part of the seam. The most common miospore taxa are Laevigatosporites spp., Cyclogranisporites orbicularis, Punctatosporites minutus and Endosporites globiformis. The miospores tend to be poorly preserved and relatively homogeneous in population frequencies and vertical distribution within the coal. The overall coal assemblage also closely resembles a vertical miospore spectrum from adjacent shales. These palynological characteristics and the high ash content of the coal suggest that the Dalton is mainly an allochthonous deposit. Only the top layer, which contains coal balls, appears to have fonned autochthonously in a peat swamp.

SPHENOPTERIDIUM AND TELANGIOPSIS IN A DIPLOPTERIDIUM-LIKE ASSOCIATION FROM THE VIRGILIAN (UPPER PENNSYLVANIAN) OF NEW MEXICO.

The highly fossiliferous Virgilian (Upper Pennsylvanian) shales of the Kinney Brick Company quarry near Albuquerque, New Mexico, contain a diversified flora dominated by walchian conifers and neuropterid pteridosperms. Its other components include a specimen of Telangiopsis sp. and abundant material of Sphenopteridium manzanitanum, n. sp., a highly variable foliar form. Both genera are characteristically restricted to the Upper Mississippian, with the exception of one basal Pennsylvanian occurrence. Their occurrence together in the Kinney sediments and their possession in common of distinctive surficial ornamentation suggest that they represent dissociated parts of Diplopteridium, a very rare European Lower Carboniferous taxon. Other associated plants show later Paleozoic or even Early Mesozoic characteristics, which, together with the Mississippian elements, distinguish the Kinney site as paleobotanically unique.

Sphenopteridium and Telangiopsis in a Diplopteridium-Like Association from the Virgilian (Upper Pennsylvanian) of New Mexico

The highly fossiliferous Virgilian (Upper Pennsylvanian) shales of the Kinney Brick Company quarry near Albuquerque, New Mexico, contain a diversified flora dominated by walchian conifers and neuropterid pteridosperms. Its other components include a specimen of Telangiopsis sp. and abundant material of Sphenopteridium manzanitanum, n. sp., a highly variable foliar form. Both genera are characteristically restricted to the Upper Mississippian, with the exception of one basal Pennsylvanian occurrence. Their occurrence together in the Kinney sediments and their possession in common of distinctive surficial ornamentation suggest that they represent dissociated parts of Diplopteridium, a very rare European Lower Carboniferous taxon. Other associated plants show later Paleozoic or even Early Mesozoic characteristics, which, together with the Mississippian elements, distinguish the Kinney site as paleobotanically unique.

Mississippian Clinoform: Lithologic and Paleoecologic Diversity Amid Slopes, Slides, and Mounds

On February 26-29, twenty-three paleontologists, stratigraphers, and sedimentologists participated in a field workshop on the paleoecology and sedimentation of the Mississippian Fort Payne Formation in southcentral Kentucky and adjacent Tennessee. The group stayed at Sulphur Creek Resort on an arm of Dale Hollow Reservoir and examined Fort Payne outcrops in the Cumberland Saddle region from Columbia, Kentucky, to Celina, Tennessee, 45 miles to the south. South-central Kentucky and adjacent Tennessee lie in the Cumberland Saddle, so named for the Cumberland River, which flows to the west and southwest through the gentle structural sag between the Lexington and Nashville Domes each exposing Middle and Upper Ordovician strata (Fig. 1). In the Cumberland Saddle itself, however, a thin section of deepwater Devonian Chattanooga Shale caps these rocks and above it lies a very well exposed Lower to Middle Mississippian section including the Fort Payne Formation (lowest), Warsaw Formation, St. Louis Formation, and the St. Genevieve (Monteagle) Limestone, capped on the margins of the saddle by basal Pennsylvanian sandstones and shales. The most widespread and best exposed of these units are the Fort Payne and Warsaw Formations, largely because the PlioPleistocene entrenchment of the Cumberland River has produced sharp, local relief of 150 to almost 300 feet with a dense pattern of dendritic drainage so that outcrops abound. Here one can see exceptionally well in a small area a complex marine clinoform, commonly 250-290 feet thick, that contains diverse terrigenous and carbonate facies (Fig. 2). Although the Cumberland Saddle itself covers more than eight counties, it is small in comparison to all the Fort Payne, which extends from the Black Warrior Basin of Alabama through Tennessee and Kentucky into the Illinois Basin. In Kentucky and adjacent states Fort Payne deposition occurred after and to the southwest of the fine-grained sandstones, siltstones, and shales of the Borden Formation, which also has a clinoform structure. The two are separated by a widespread glauconite, the Floyds Knob Glauconite, which can be traced up the clinoform onto shelf beds. Plentiful shallow wells and complete geologic quadrangle mapping add to the attractions of the Cumberland Saddle as a field laboratory. From the viewpoint of paleoecology the Fort Payne Formation has special interest, because it is a marine clinoform (Fig. 2) rich in diverse lithologies: at least three types of shales (black silty shale, medium, dark gray, silty dolomitic shale, and fossiliferous green shale) plus a diverse array of limestones most of which have a predominant pelmatozoan echino-

Reservoir Geology of the Basal Pennsylvanian Buchanan"Sandstone, Lawrence Field, Illinois"

Reservoir Geology of the Basal Pennsylvanian Buchanan"Sandstone, Lawrence Field, Illinois"

Depositional Environments and Facies Analysis of the Cherokee Group in West-Central Kansas

The Cherokee Group of early Desmoinesian Pennsylvanian age in west-central Kansas is comprised of a mixed siliciclastic and carbonate sequence. It was deposited in environments that are transitional from continental to marginal marine as the Hugoton Sea transgressed the Mississippian unconformity on to the Central Kansas uplift. Sandstones of the Cherokee Group are important oil reservoirs in west-central Kansas, but they are highly variable and difficult to predict. Core studies and subsurface analysis reveal two persistent and widespread limestone beds that form useful stratigraphic markers within the Cherokee. They provide a framework for facies analysis and regional mapping that may be useful as a predictive tool for oil exploration. Six basic lithofacies are interpreted from lithologies and sedimentary structures observed in cores obtained from four wells in eastern Ness County: (1) basal Pennsylvanian conglomerate, (2) fluvial sands, (3) fine-grained tidal flat deposits, (4) shallow-marine limestones, (5) shoreline sands and tidal channel sands, and (6) braided stream, sandy conglomerates. These facies are correlative with components of an ideal Kansas cyclothem. Two transgressive-regressive cycles are identified and maximum transgression is correlated with two widespread limestone beds. Following burial of the Mississippian karstic surface, deposition of peritidal sediments occurred on a uniform shallowmore » shelf, punctuated by periods of subaerial exposure and weathering. Clastics derived from the eroding Central Kansas uplift were probably supplied to the coastal plain by braided streams and reworked by coastal processes.« less

Regional Paleotopographic Trends and Production, Chesterian and Morrowan Strata, Western Interior

Late Chesterian (Mississippian) and Morrowan (Pennsylvanian) unconformity-bounded packages in the Western Interior have traditionally been viewed as sequences separated by a regional basal Pennsylvanian unconformity. Analysis of alluvial valley trends and paleontological data suggests that these sequences are related and formed in response to multiple relative sea level fluctuations initiated in the Chesterian which continued throughout the Pennsylvanian. The Darwin, Tyler, Morrowan, and Humbug formations of the Western Interior appear to have formed in retrogradational parasequence sets of alluvial valley fills and marine transgressive systems tracts repeatedly developed around the flanks of the transcontinental arch. Relative sea level rises following each major incisement created a complex intertonguing of marine strata responsible for fluvial aggradation of each valley system. These sequences progressively backstep and grow younger toward the transcontinental arch, where Atokan and Desmoinesan strata cap the oldest preserved surfaces. At least four major paleodrainage basins have been identified, and valley-fill production has been established in three of these. The previously unrecognized age equivalency of these formations provides a new regional sequence stratigraphic interpretation which has hydrocarbon exploration implications in frontier areas of Utah and Colorado. Seismic resolution and an understanding of hydrocarbon migration paths hold the key to developing newmore » exploration trends.« less

Use of geophysical logs to estimate water quality of basal Pennsylvanian sandstones, southwestern Illinois : Ground WaterV27, N5, Sept–Oct 1989, P682–688

Use of geophysical logs to estimate water quality of basal Pennsylvanian sandstones, southwestern Illinois : Ground WaterV27, N5, Sept–Oct 1989, P682–688

REPLY TO the preceding Discussion by John Logan of “Use of Geophysical Logs to Estimate Water Quality of Basal Pennsylvanian Sandstone, Southwestern Illinois”

REPLY TO the preceding Discussion by John Logan of “Use of Geophysical Logs to Estimate Water Quality of Basal Pennsylvanian Sandstone, Southwestern Illinois”