Geological Magazine



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Burrowing below the basal Cambrian GSSP, Fortune Head, Newfoundland


JAMES G. GEHLING a1c1, SÖREN JENSEN a2, MARY L. DROSER a2, PAUL M. MYROW a3 and GUY M. NARBONNE a4
a1 South Australian Museum, North Terrace, Adelaide, South Australia 5000, Australia
a2 Department of Earth Sciences, University of California, Riverside, California 92521, USA
a3 Department of Geology, The Colorado College, Colorado Springs, CO 80903, USA
a4 Department of Geological Sciences, Queen's University, Kingston, Ontario K7L 3N6, Canada

Abstract

The range of Treptichnus pedum, the index trace fossil for the Treptichnus pedum Zone, extends some 4 m below the Global Standard Stratotype-section and Point for the base of the Cambrian Period at Fortune Head on the Burin Peninsula in southeastern Newfoundland. The identification of zigzag traces of Treptichnus isp., even further below the GSSP than T. pedum in the Fortune Head section, and in other terminal Proterozoic successions around the globe, supports the concept of a gradational onset of three-dimensional burrowing across the Proterozoic–Cambrian boundary. Although T. pedum remains a reasonable indicator for the base of the Cambrian Period, greater precision in the stratotype section can be achieved by a detailed re-evaluation of the stratigraphic ranges and the morphological variation of ichnotaxa included in the T. pedum Zone.

(Received June 22 2000)
(Accepted January 5 2001)


Correspondence:
c1 Author for correspondence: gehling.jim@saugov.sa.gov.au


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