A New Decapod Trackway from the Upper Cretaceous, James Ross Island, Antarctica

Abstract

ABSTRACT. A new trace fossil, Foersterichnus rossensis igen. nov. and isp. nov., is described from the Coniacian Hidden Lake Formation, James Ross Island, Antarctica. The trace fossil is a trackway comprising straight, or slightly curving, paired rows of elongate to tear-shaped impressions, parallel or slightly inclined to the long axis of the trackway. Foersterichnus is interpreted to be the trackway of a brachyuran decapod crustacean. It occurs in transgressive shallow marine deposits formed above the storm wave base in a shelf setting. Preservation of the trackway may have been linked to a rapid deoxygenation event during drowning that led to cessation of bioturbation allowing preservation of mixed layer trackways.

Marine volcaniclastics of the Hidden Lake Formation (Coniacian) of James Ross Island, Antarctica: an enigmatic element in the history of a back-arc basin

“…The formation shows a broadly similar overall finingupwards trend throughout this proximal outcrop belt, probably reflecting a decrease in erosion/transport and sedimentation rates due to the progressive stabilisation of the margin, as tectonism waned and volcanic activity gradually declined. The suggestion of reduced sedimentation rates in the late Coniacian is supported by the recognition of Glossifungites 'firm-ground' surfaces and a general increase in trace-fossil diversity in the uppermost Hidden Lake Formation (Buatois & L6pez-Angriman 1992b;Buatois 1995;Pirrie et al 2004).…”

“…The typical shallow-water marine elements (oysters, corals and bryozoans) are fragmented, occur in massflow deposits and are clearly derived. A relatively diverse suite of trace fossils is also present in the formation and includes the ichnogenera (Pirrie et al 2004). In addition to the invertebrate fauna, the Hidden Lake Formation contains very abundant fossil wood, which is commonly charcoalified.…”

“…The sandstones contain an abundance of zoned plagioclase and fresh clinopyroxene, and laminae rich in magnetite occur locally. Whilst plant debris and wood fragments are common (many of which are charcoalified), macrofossils are scarce overall, being 5 restricted to discrete mudstone intervals• The ichnofauna is of low diversity (Buatois & L6pez-Angriman 1992b;Pirrie et al 2004).…”

“…This is consistent with the mud-rich composition of the mass-flow deposits, in contrast to the sand-rich, volcaniclastic sediments derived from the arc. The macrofauna and ichnofauna is of low diversity in most sections, although an increase in the trace-fossil diversity has been recorded in the uppermost levels of the formation (Buatois & L6pez-Angriman 1992b;Pirrie et al 2004), heralding the transition into the fossiliferous, intensely bioturbated shelf sediments of the Marambio Group. A distinctive variant of the association is found at locality 3 (Fig.…”

Sinusichnus,a trace fossil from Antarctica and Venezuela: expanding the dataset of crustacean burrows

“…2006). The ichnological content of the Hidden Lake Formation has been addressed in a number of papers (Buatois & López Angriman 1992b; Buatois 1995; Pirrie et al . 2004), but Sinusichnus has not been recorded previously in this unit.…”