Archer, Allen W., and Erik P. Kvale, 1993. Origin of gray-shale lithofacies ("clastic wedges") in U.S. midcontinental coal measures (Pennsylvanian): an alternative explanation, in J. C. Cobb, and B. Cecil, eds., Modern and Ancient Coal-Forming Environments: Geological Society of America, Special Paper 286, p. 181-192.

Abstract:Cyclic laminations in gray shales are noted above many major coal seams in the Illinois Basin. These features, which are termed "tidal rhythmites," indicate signficant tidal influence during deposition of the roof strata. Many existing models, however, suggest fluvial dominance and crevasse splay deposition for such gray shales.

Based on sedimentological and paleogeographical considerations, appropriate depositional models require micro- to mesotidal environments, limited wave reworking, and a mud- dominated, tropical setting. Following these requirements, tidally influenced estuarine/deltaic models can be generated for roof strata of many Illinois Basin coals. This model is based upon modern mud-rich tidally influenced estuaries and deltas in near equatorial settings and can be used to explain occurrence of shales that lack obvious marine influence (based upon paleontology) above low-sulfur coals in the Illinois Basin.

Feldman, Howard R., Allen W. Archer, Erik P. Kvale, Christopher R. Cunningham, Christopher G. Maples, and Ronald R. West, 1993. A tidal model for Carboniferous conservat Lagerstatten formation: Palaois, 8:485-498.

Abstract:Rapid deposition of laminated sediments in tidally influenced estuaries can explain many characteristics of some Carboniferous Konservat-Lagerstatten. In modern environments each tide can potentially deposit a layer of normally graded mud. Localized depositional rates as high as 1 cm or more of sediment per week can occur in tdal estuarine settings. Characteristic periodicites in lamination thicknesses reflect neap-spring cycles and other earth-moon orbital parameters; these periodicities can be used to identify tidal deposits in Carboniferous rocks. Commonly preserved in tidal sedimentary rocks are neap/spring cycles and the semi-diurnal tidal inequality. Such deposits are widespread in the mid-continental U.S.

The major features of the tidal model of Lagerstatten formation are: sediment is delivered to the site by each tide; high rates of deposition result in rapid burial of carcasses at the sediment-water interface; high depositional rates, high turbidity, and fluctuating or brackish salinity reduce or prevent bioturbation, colonization by benthic invertebrates, and scanenging; the combination of semipermeable muddy sediment and high levels of organic carbon may lead to anoxic porewater, and will also prevent bioturbation and scavenging of buried skeletons. The superficial similarity of tidal laminations to lacustrine varves and the general lack of marine benthos in tidal deposits can lead to mistaken limnic interpretations of mud-dominated parts of estuarine facies.

Feldman, Howard R., Mark A. Brown, and Allen W. Archer, 1993. Implications for sediment stability from benthic assemblages in Carboniferous grainstones: Evidence from the Salem Limestone (Mississippian, Indiana), in B. D. Keith, and C. W. Zuppann, eds., Mississippian Oolites of North America, American Association of Petroleum Geologists, Studies in Geology no. 35, p. 115-128.

Abstract:Within the Mississippian (Valmeyeran) strata of Indiana, the uppermost Harrodsburg and lowermost Salem limestons contain a variety of grainstone facies that were deposited within a tide- and wave-dominated, shallowing-upward sequence. Compositions of autochthonous fossil assemblages in each facies are interpreted to have been constrained primarily by sediment stability. For example, echinoderm-bryozoan- brachiopod assemblages apparently thrived on stable substrates. Conversely, gastropod- dominated assemblages lived on frequently reworked, tidally influenced substrates. Low- diversity assemblages lived on substrates that were almost continually reworked. Faunal diversity decreased with increasing sediment mobility because of the increased (biological) energy required to maintain a life position at the sediment-water interface. Within modern analogs, a decrease in faunal diversity commonly correlates with increased sediment mobility.

Lanier, William P., Howard R. Feldman, and Allen W. Archer, 1993. Tidally modulated sedimentation in a fluvial to estuarine transition, Douglas Group, Missourian- Virgilian, Kansas: Journal of Sedimentary Petrology, 63:860-873.

Partial Abstract: The Tonganoxie Sandstone Member of the Stranger Formation (Douglas Group, Upper Pennsylvanian, Kansas) was deposited in a funnel-shaped, northeast-southwest-trending paleovalley that was incised during the uppermost Misourian sealevel lowstand and backfilled during the subsequent transgression. Quarry exposures of the Tonganoxie near Ottawa, Kansas, include ~5 m of sheetlike, vertically accreted siltstones and sandy siltstones, bounded above and below by thin coals with upright plant fossils and paleosols.

Analysis of stratum-thickness variations through the succession suggests that dies significantly influenced sediment deposition. A fluvial-to-estuarine transitional depositional setting is interpreted by analogy with modern depositional settings that show similar physical and biogenic sedimentary structures.