Jack A. Wolfe
Douglas J. Nichols
Robert A. Spicer
1987
<p>Cretaceous<span> </span>floras<span> in Alaska, when compared to those at mid-latitudes, generally indicate later appearances in Alaska of major clades and major leaf morphologies. Compared to mid-latitude </span>floras<span>, </span>Alaskan<span> Late </span>Cretaceous<span> </span>floras<span> contain few major clades. The </span>Alaskan<span> clades diversified but at a low taxonomic level. Migrational pathways into high latitudes were probably along streams. Similar patterns characterized the </span>Alaskan<span> </span>Tertiary<span>, although some southward migrations of lineages occurred during the Neogene. Review of other </span>Arctic<span> paleontological data from Ellesmere Island, previously used to suggest that the </span>Arctic<span> was a major center of </span>origin<span> during the Late </span>Cretaceous<span>, indicates that the ages of supposedly substantiating dinoflagellate </span>floras<span> were misinterpreted. When the dinoflagellate data are interpreted according to standard methodology, first occurrences of genera and species groups on Ellesmere are, like the </span>Alaskan<span> occurrences, later than first occurrences at middle latitudes. </span></p>
application/pdf
10.1017/S0094837300008599
en
Cambridge University Press
Alaskan Cretaceous-Tertiary floras and Arctic origins
article