Succession, palaeoecology, evolution, and speciation of Pennsylvanian non‐marine bivalves, Northern Appalachian Basin, USA

Abstract

Seventeen horizons of non-marine bivalves are described within the Appalachian succession from the base of the Pottsville Group of Westphalian A-B age to the Uniontown coal of Stephanian C age at the top of the Carboniferous System. A new highly variable fauna of Anthraconaia from the roof shales of the Upper Freeport coal near Kempton, west Maryland, dates from late Westphalian D or very early Cantabrian time, on the evidence of non-marine shells and megafloras. Below this horizon, the Appalachian sequence reveals zones of Anthraconauta phillipsii and Anthraconauta tenuis in the same order as in Britain, whereas faunas of Anthraconaia of these zones are less common and differ from those of Britain. In all horizons above the Upper Freeport coal all non-marine bivalve faunas consist of stages in the sequences of two natural species, the groups of Anthraconaia prolifera and Anthraconaia puella-saravana. The first shows evidence of having lived in well-oxygenated, probably shallow, fresh water conditions of relatively wide extent. The second group lived preferentially in a plant-rich environment of relatively stagnant fresh water. Both groups are found in horizons associated with coal seams and may be seen together in the same habitats, but diagrams of variation (pictographs) suggest that there was no interbreeding between the two groups in either the Northern Appalachians or in southern Germany where the species split was first recognized. In the northern Spanish coalfields of Guardo-Valderrueda and Central Asturia, facies evidence suggests how an initial split may have taken place in the same morphological directions and into the same palaeoenvironments as the later split into two species.Appalachian deposition was generally slow and intermittent with frequent palaeosols. There is also evidence of erosion and of small palaeontological breaks in the sequence, especially near the eastern edge of the Northern Appalachian Basin in western Maryland. The amount of accumulated sediment was less than one-tenth of that of western Europe when basin centre deposition is compared. We found no evidence of a major palaeontological break representing Westphalian D strata overlain by Stephanian C strata. We figure non-marine bivalve faunas of Stephanian B age in association with the Pittsburgh and the Little Pittsburgh coals. Two new species of non-marine bivalves are described: Anthraconaia anthraconautiformis sp. nov. and Anthraconaia extrema sp. nov.

Record of glacial–eustatic sea-level fluctuations in complex middle to late Pennsylvanian facies in the Northern Appalachian Basin and relation to similar events in the Midcontinent basin

“…Similar facies seen in outcrop, 6 km westward at Kempton (Fig. 3) were interpreted as lake deposits, because they contain a fresh-water bivalve species (Eagar and Belt, 2003) and the xiphosauran, Euproöps, and because C-S geochemistry at that site indicates fresh water (Kerns, 2004). Hence, the laminated roofshales above the Upper Freeport coal in the Scanlon sections are considered also to be of lacustrine origin.…”

“…Near the base of this interval, the Upper Freeport coal is widely correlated because it has been extensively mined throughout the Northern Appalachian Basin (Fig. 1), and also because it has a distinctive dark laminated roof shale that contains nonmarine fauna, such as the conchostracan Paleolimnadiopsis (Williams, 1960) and the bivalve Anthraconaia (Eagar and Belt, 2003).…”

“…The horizontal extent of marine transgressions is determined by comparing faunas of highstand deposits in each cycle, based on the criteria used by Williams (1960) for marine to brackish and by Eagar and Belt (2003) for fresh-water, and plotting their extent in the NAB (Fig. 14).…”

Ostracods from freshwater and brackish environments of the Carboniferous of the Midland Valley of Scotland: the early colonization of terrestrial water bodies

“…Anthraconaia and Carbonicola are commonly associated with Naiadites in Pennsylvanian freshwater Coal Measures (for example, Jenkins, 1960;Hartley, 1993;Brand, 1996;Eagar & Belt, 2003). Anthraconaia, Carbonicola, Curvirimula and Naiadites occur in brackish (Ballèvre & Lardeux, 2005) or lacustrine Mississippian sediments (Guirdham et al 2003) and freshwater Pennsylvanian sediments (Brand, 1994;Anderson et al 1999;Falcon-Lang, 2005;Falcon-Lang et al 2006).…”

Paleoenvironmental analysis of the Glenalum Tunnel coal and roof rock, southern West Virginia—Implications for sulfur origin and trends

“…Upward-coarsening of the lacustrine shale into siltstone reflects shallowing and infilling of the lake by encroaching levees, crevasse splays, and minor deltas (Elliott, 1974;Horne et al, 1978;Reading and Collinson, 1996). The rare occurrence of the bivalve Anthraconaia and 'Spirorbis' (now recognized as a spirorbid Micronconchus), and siderite beds and nodules could indicate a transition from a freshwater lake to a slightly brackish coastal bay, though these taxa are also found in Pennsylvanian freshwater facies (Chesnut, 1981;Eagar and Belt, 2003;Taylor and Vinn, 2006). Cochlichnus is a characteristic trace fossil of the Scoyenia and Mermia ichnofacies, both of which characterize alluvial floodplain and lakes (Buatois and Mangano, 1995;MacEachern et al, 2010).…”