Mollusks from the upper Shackleton Limestone (Cambrian Series 2), Central Transantarctic Mountains, East Antarctica

Thomas M Claybourn,Timothy P Topper,Sarah M Jacquet,Glenn A Brock,Lars E Holmer,Christian B Skovsted

doi:10.1017/jpa.2018.84

Abstract

AbstractAn assemblage of Cambrian Series 2, Stages 3–4, conchiferan mollusks from the Shackleton Limestone, Transantarctic Mountains, East Antarctica, is formally described and illustrated. The fauna includes one bivalve, one macromollusk, and 10 micromollusks, including the first description of the speciesXinjispira simplexZhou and Xiao, 1984 outside North China. The new fauna shows some similarity to previously described micromollusks from lower Cambrian glacial erratics from the Antarctic Peninsula. The fauna, mainly composed of steinkerns, is relatively low diversity, but the presence of diagnostic taxa, including helcionelloidDavidonia rostrata(Zhou and Xiao, 1984), bivalvePojetaia runnegariJell, 1980, cambroclavidCambroclavus absonusConway Morris in Bengtson et al., 1990, and bradoriidSpinospitella coronataSkovsted et al., 2006, as well as the botsfordiid brachiopodSchizopholis yorkensis(Ushatinskaya and Holmer in Gravestock et al., 2001), in the overlying Holyoake Formation correlates the succession to theDailyatia odysseiZone (Cambrian Stages 3–4) in South Australia.

Highlights

During the early Cambrian, East Antarctica was sutured between the southern coast of Australia, Southeast Africa, and India and located at tropical latitudes (Brock et al, 2000; Torsvik and Cocks, 2013a, b)
This paper focusses on descriptions and biostratigraphy of eight helcionelloids, two pelagiellids, one scenellid, and the bivalve Pojetaia runnegari Jell, 1980
These discoveries have formed the bulk of knowledge of lower Cambrian faunas from Antarctica and confirm strong biostratigraphic and paleobiogeographic links with South Australia (Brock et al, 2000; Betts et al, 2016a, 2017), Northeast Greenland (Skovsted, 2004, 2006b), and North China (Yang et al, 2015) during Cambrian Series 2, Stages 3–4

Summary

Introduction

During the early Cambrian, East Antarctica was sutured between the southern coast of Australia, Southeast Africa, and India and located at tropical latitudes (Brock et al, 2000; Torsvik and Cocks, 2013a, b). Parkhaev in Gravestock et al (2001) created loosely defined molluscan assemblage ‘zones’ for their work on the biostratigraphy of the lower Cambrian succession in the Stansbury Basin, South Australia These were defined according to the presence of certain key taxa, and four. Geological setting and previous work.—The bulk of fossil material recovered is derived from an archaeocyath-rich biohermal unit near the top of a stratigraphic section (HRA) measured through the Shackleton Limestone and the overlying dark nodular carbonates and interbedded calc-siltsones of the Holyoake Formation. These rock units make up part of the Byrd Group These discoveries have formed the bulk of knowledge of lower Cambrian faunas from Antarctica and confirm strong biostratigraphic and paleobiogeographic links with South Australia (Brock et al, 2000; Betts et al, 2016a, 2017), Northeast Greenland (Skovsted, 2004, 2006b), and North China (Yang et al, 2015) during Cambrian Series 2, Stages 3–4

Stratigraphic correlation

Materials and methods

Systematic paleontology

Order and family uncertain