On the basis of the nomenclature of Dunham (1962), Hartenfels (2011) defined 19 modified microfacies types for outer shelf settings, which can be assigned to the standard facies zones (1B to 4) of Flügel (2004) and can be divided into two facies series, MF-A: facies below storm wave base, MF-B: facies supposedly within the influence of storm waves or bottom currents. According to Hartenfels (2011), this modification is necessary because hemipelagic or neritic carbonates cannot be classified with sufficient differentiation in the classic microfacies zone model of Wilson (1975) and its critical review by Flügel (2004). However, it should be noted that current-induced sedimentation in the subphotic, pelagic realm may originate from contourites rather than from storms. In the Rhenish Massif, the modified classification sensu Hartenfels (2011) was successfully applied by Lüddecke et al. (2017) on the Upper Ballberg Quarry, a middle Famennian hemipelagic seamount section. Since the Martenberg section was deposited on top of a drowned volcanic seamount, an older but comparable depositional setting is assumed to interprete the microfacies (Fig. 13).
(2011) Pl7 Pro 4.5 Crackl
The middle-upper Frasnian palaeogeographic setting of the volcanic Martenberg seamount can be characterised as constantly shallow pelagic and below the euphotic zone. This is in accord with the rich conodont assemblages and macrofaunas (e.g. Holzapfel 1882; Paeckelmann 1936; House and Ziegler 1977) that are dominated by cephalopods associated with specialised, subphotic benthic faunal elements, such as buchiolid and other bivalves, rare gastropods, very rare proetid trilobites, and small-sized, deeper-water solitary rugose corals. The fauna and microfacies of Bed R represent MF A4 sensu Hartenfels (2011), which suggests calm and slow deposition below the photic zone and storm wave base. Based on the strong bioturbation, the sea-floor was fully oxic. Microstromatolites (Fig. 13a2) are typical for such condensed pelagic sedimentation (compare Préat et al. 2008; Hartenfels 2011; Hartenfels and Becker 2016). Dacryoconarid nests may stem from the burrowing (Fig. 13a1). 2ff7e9595c
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