A preliminary study of Ashgill carbonate beds from the lower part of the Fosses Formation (Condroz, Belgium)

Abstract

The sedimentology and palaeontology of carbonate beds in the lower part of the Fosses Formation (Ashgill of the Condroz area, central Belgium) have been investigated. Two depositional interpretations are suggested: deposition either near a platform-ramp margin as bioclastic turbidites and interbedded shales or on a shelf as a transgressive sequence following a regressive event. Faunal affinities with the Baltic area and Wales are confirmed, and the location of Belgium in the tropics during the Ashgill is supported by the calcareous algae and the coral fauna.

Early Palaeozoic orogenic events north of the Rheic suture (Brabant, Ardenne): A review

“…Chitinozoan biostratigraphy reveals that these conglomeratic horizons have a Llandovery age (c. 438 Ma) [90][91][92]. They also contain lower to Middle Ashgill limestone boulders indicative of a nearby carbonate platform [87]. Detailed biostratigraphy furthermore identified two disconformities in the Ordovician-Silurian transition period [90,91].…”

Rugose corals from the Upper Ordovician Sholeshook Limestone of southwest Wales with an assessment of the coral affinities and biofacies

“…The coral faunas of both the Portrane and Sholeshook limestones are similar to faunas of the Norwegian 5a and Estonian Vormsi and Pirgu stages (Kaljo et al ., ), as well as contemporaneous Katian faunas from Belgium (Tourneur et al ., ), North Wales, North Yorkshire and the Lake District, but differ markedly from the fauna at Girvan which has North America affinities (Wang, ; Orita and Ezaki, ). Welsh coral faunas form part of a Euroasiatic faunal province dominated by heliolitids (Yang, ; Webby, ).…”

Chitinozoan biostratigraphy of the Upper Ordovician of Faulx-les-Tombes (central Condroz Inlier, Belgium)

“…crinoids, trilobites, bryozoans, corals, echinoderm debris, cystoids, molluscs and algae (Tourneur et al, 1993). At some localities, as in the study area, the lower beds of the Fosses Formation contain a matrixsupported conglomerate: black, well rounded shale pebbles in a calcareous shale to silt matrix (Michot, 1954).…”

“…At some localities, as in the study area, the lower beds of the Fosses Formation contain a matrixsupported conglomerate: black, well rounded shale pebbles in a calcareous shale to silt matrix (Michot, 1954). The limestone cobble conglomerate of Cocriamont (Stainier, 1926;Tourneur et al, 1993), however, formally supposed to be a lateral facies change of the matrix-supported conglomerate at the base of the Fosses Formation, has recently been shown to be situated at a much higher level in the overlying Génicot Formation (Vanmeirhaeghe and Verniers, 2004). It is supposed to be the lithological expression of the sea-level drop caused by the Hirnantian glaciation (Vanmeirhaeghe and Verniers, 2004.…”

“…These extensive acritarch data, however, did not allow a detailed biozonation. After this work, biostratigraphical studies were undertaken only sporadically, such as the study of the Silurian rocks of Neuvillesous-Huy (Maes et al, 1978), the study of the brachiopods and trilobites of the Upper Ordovician Fosses Formation (Sheehan, 1987;Lespérance and Sheehan, 1987), the study of the graptolites and acritarchs of the lower Llanvirn of the Huy Formation (Servais and Maletz, 1992) and a general study of the Fosses Formation in the Puagne area (Tourneur et al, 1993). More recently, fieldwork in the Condroz Inlier was reactivated, resulting in several studies of the Ordovician of the Condroz Inlier (De Geest, 1998 ms;Billiaert, 2000ms, Vanmeirhaeghe, 2001Vanmeirhaeghe, 2002, ms;Verniers, 2002, 2004).…”