Latest Chesterian (Carboniferous) initiation of Gondwanan glaciation recorded in facies stacking patterns and brachiopod paleocommunities of the Antler foreland basin, Idaho

Gigantoproductid brachiopod storm shell beds in the Mississippian of South China: implications for their palaeoenvironmental and palaeogeographical significances

“…In this study, multiple lines of evidence suggest that the accumulation of shells in Gigantoproductus shell beds is related to winnowing and transporting driven by storm surges, which is the principle agent of shell accumulation (Aigner, 1985;Flügel, 2004). First, the taphonomy of Gigantoproductus shells is usually characterized by disarticulation, convex-up and high fragmentation (Figs 3,5), which are obvious characteristics in storm shell beds (Jeffery & Aigner, 1982;McFarland et al, 1999;Butts, 2005;Jin et al, 2013). Second, the occurrences of sedimentary structures of tempestites in the shell beds, including sharp and erosional base, internal erosional surface and uppermost parallel lamination and ripple bedding (Fig.…”

“…Taphonomic studies revealed that the shell assemblage dominated by convex-down and -up shells was caused by low and high water energy, respectively (Jeffery & Aigner, 1982;McFarland et al, 1999;Butts, 2005;Chen et al, 2013). Hence, in the GSB 1 , the high contents of shells in convex-down orientation indicate that the shells were affected by low hydrodynamic energy before they were buried (Jeffery & Aigner, 1982;Butts, 2005). According to the observation of 45 convex shells on the surface of the YSB 2 , 35 shells (78%) are convex-up and 10 shells (22%) are convex-down (Fig.…”

“…Several storm shell beds have been documented in the United States and southwest England in the Mississippian (Jeffery & Aigner, 1982;Butts, 2005). In these shell beds, the shells are characterized by different taphonomic types varying from articulated, convexdown and low fragmented shells to disarticulated, convex-up and high-breakage shells, which indicate that they are formed under low and high water energy respectively, driven by storms (Jeffery & Aigner, 1982;Butts, 2005).…”

“…Storm shell beds, which are one common type of tempestites and featured by accumulation of shells, were documented during the icehouse periods of the late Ordovician (Lehman & Pope, 1989;Davis, 1999;Jin et al, 2013), early Silurian (Johnson, 1989;Li & Rong, 2007;Jin, 2008) and early Carboniferous (Jeffery & Aigner, 1982;Butts, 2005) and during greenhouse climate, as in the middle Ordovician (McFarland et al, 1999), late Permian (Simões & Kowalewski, 1998), early Triassic (Boyer et al, 2004), late Jurassic (Fürsich, 1982) and late Early Cretaceous (Fürsich & Kauffman, 1984). Common to all is that their formation is connected to hurricane formation in the tropical belt of the respective timeslice.…”

“…In storm shell beds, taphonomic characteristics of shells are generally characterized by amalgamation of articulated, disarticulated and fragmented shells with non-directional distribution (Aigner, 1985;Jin et al, 2013), ranging from proximal tempestites with more disarticulated and fragmented shells to distal tempestites with more articulated and less fragmented shells (Johnson, 1989;Lehman & Pope, 1989). Sedimentologic features of tempestites also vary from proximal tempestites to distal tempestites dominated by grainstone and mudstone respectively, implying different hydrodynamic energy driven by storm surges and water depths (Aigner, 1985;Butts, 2005;Dattilo et al, 2012). In addition, a comprehensive study on the relationships between taphonomy of shell beds and their palaeogeographical locations was conducted in the late Ordovician (Jin et al, 2013).…”