Unformatted text preview: Several Neoproterozoic * oolites * contain unusually large ooids, some reaching diameters of up to 16 mm. While lower nuclei supply and higher ooid growth rate may have prevailed prior to the evolution of carbonate *-secreting organisms, neither difference can explain the presence of giant ooids in Neoproterozoic deposits because Archean * through Mesoproterozoic * ooids rarely exceed 5 mm in diameter. In the presence of lower nuclei supply and higher growth rate, high average water velocity may have allowed growth of such large ooids. Higher average water velocity could have been due to a prevalence of carbonate ramps over rimmed shelves during Neoproterozoic time....
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- Spring '08
- Neoproterozoic G iant Ooids, average water velocity, Ooid Size, lower nuclei supply