Shelly fossils from the lower Cambrian White Point Conglomerate, Kangaroo Island, South Australia

• The lower Cambrian (Series 2) White Point Conglomerate (WPC) on Kangaroo Island, South Australia contains exoticclasts representing a diverse array of lithologies, including metamorphics, chert, sandstone, and abundant carbonates,notably archaeocyath-rich bioclastic limestone. Acetic acid digestion of the WPC bioclastic limestone clasts reveals adiverse shelly fauna. This assemblage includes abundant organophosphatic brachiopods such as Cordatia erinae Brockand Claybourn gen. et sp. nov., Curdus pararaensis, Eodicellomus elkaniformiis, Eohadrotreta sp. cf. E. zhenbaensis,Eoobolus sp., Kyrshabaktella davidii, and Schizopholis yorkensis. Additional shelly taxa include the solenopleurid trilobiteTrachoparia? sp., the tommotiids Dailyatia odyssei, Dailyatia decobruta Betts sp. nov., Kelanella sp., and Lapworthellafasciculata, spines of the bradoriid arthropod Mongolitubulus squamifer, and several problematica, such as Stoibostrombuscrenulatus and a variety of tubular forms. The upper age limit for the WPC is constrained by biostratigraphic data fromthe overlying Marsden Sandstone and Emu Bay Shale, which are no younger than the Pararaia janeae Trilobite Zone(Cambrian Series 2, Stage 4). The shelly fossil assemblage from the WPC limestone clasts indicates an upper Dailyatiaodyssei Zone (= Pararaia tatei to lower P. janeae trilobite zones), equivalent to the Atdabanian–early Botoman of theSiberian scheme. This contrasts with the previously suggested late Botoman age for the limestone clasts, based on the diversearchaeocyath assemblage. The minor age difference between the WPC and its fossiliferous limestone clasts suggestsrelatively rapid reworking of biohermal buildups during tectonically-active phases of deposition in the Stansbury Basin.

Ämnesord

NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Geologi (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences -- Geology (hsv//eng)

Nyckelord

Brachiopoda

Trilobita

Tommotiida

chronostratigraphy

early Cambrian

Australia.

Diversity of life

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ref (ämneskategori)

art (ämneskategori)