Geological Magazine

Nd isotope composition of early Cambrian discrete basins

a1 Institute of Precambrian Geology and Geochronology, Russian Academy of Science, 199034 St. Petersburg, Russia
a2 Institute of Earth Sciences, Historical Geology and Palaeontology, Uppsala University, Norbyvägen 22, SE-75236 Uppsala, Sweden


A Nd isotope map of early Cambrian epeiric basins has been inferred from the Nd isotopic signature recorded in phosphatic Small Shelly Fossils. The most radiogenic [epsilon]Nd(t) values characterize water reservoirs along the Avalonian and Cadomian belts, while [epsilon]Nd(t) values of −10 to −20 were obtained in Laurentia and East Gondwanan Australia and China. Such a distribution of Nd isotope signatures results from the different provenance of early Cambrian epeiric seas: juvenile magmatic arcs and/or cordilleran for Mongolia, Siberia, Iberia and adjacent terranes, and cratonic sources for Laurentia and East Gondwana. Biogenic apatite of Small Shelly Fossils may be a useful tool for mapping of Nd isotope composition and documenting water mass exchange between discrete basins.

(Received October 17 2000)
(Revised August 23 2001)
(Accepted November 8 2001)

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