n Alas - Alaska Division of Geological & Geophysical Surveys - State ...

A CathaysIan flora
Euramerlan flora
o Southwsstsrn American Aoras
x Flora ot the conglomerate of Mount Dall
F@re 63.-Distribu tion of northern Permian floras (modllied from Chaloner and Meyen, 1973,
fig. 3).
(Hallem, 1975, p. 9). Such a geographic pattern would, Ben-Avraham, Zvi, 1981, The movement of contl-
Indeed, have provided the pathway necessary far east- nents: American Seientkt, v. 69, no. 3, p. 291ward
dispersal of Asiatfc plfmts and could have 299.
resulted in this Alaskan outpwt of the Angara flora. Chaloner, W. G., and Meyen, S. V., 1973, Carboniferous
Alternatively, this paleophy togeograph ic circum- and Permian fldras of the northern continents, In
stance can also be interpreted in the light of recent Hallam, Anthony, ed., Atlas of palaeobiogeogconcepts
of accretionary tectonostratigraphlc terrmes raphy: Amsterdam, Blsevler, p. 169-186. pls. 1-
(Jones and others, 1977, 1981; Dutro and Jones, 1979; 4.
Jones and Silberling, 1974; Beck and others, 1980; Churkin, Michad, Jr., Ebwlein, G. D., Hueber, P. M.,
Coney and others, 1980; Ben-Avrabarn, 1901), which and Marnay, S. H., 1969, Lower Devonlan land
indicate that southern Alaska is an amalgematlon of plants from grsptolite shale fn south-eastern
ellochthonous continer~tal and oceanic terranes, some Alaska: Pelaeontology, v. 22, no. 4, p. 559-573.
of which have been r~fted for thousands of kilometers Coney, p. J., Jones, D. L., M ~ J. W, ~ H., 1980, ~ ~
and accreted to their present positions. The conglom- Cordilleran suspect terranes: Nature, v. 288, no.
erate of Mount DaU lies in the Mystic temane (Jones 5789, p. 329-333.
and others, lg81), a fault-bounded exotic Dutro, J. T., dr., and Jones, D. L., 1979, Paleotectonic
probably was accreted to this part of Alaska between setting of the Carboniferous in Alaska [abs.]:
post-Early Cretaceous and early Tertiary time (Reed International Congress of Carboniferous Stratigand
others, 1979). The distribution of Zamiopteris and rephy and Geolo!gy, Qth, Washington, D.C., and
essociated plant taxa may be an important key to the Urbana, IU., 1979, Abstracts, p. 58-59.
history and interpretation of accretionary terranes in Eichwald, ~ d ~ 1871, d [~~~~~t{~-.~~~~t~l~~
this part of Alaska, and an East Asian origin for the remarks on the Mangishlak Peninsula and the
Mystic terrane merits consideration. Aleutian Islands]: Acadhie ~rn&aIe dex
Solences de St. Petersbourg Mihoires, v. 27, no.
REFERENCES CITED 4, p. 1-200, pls. 1-20 [in Rwim].
Fefilova, L. A., 1973, [Permian pteridophyta from the
Beck, Myrl, Cox, Allan, and Jones, D. L., 1980, Meso- north of the pre-Uralian depresslonJ: Leningrad,
zoio and Cenozoic micropkite tectonics of west- U.S.S.R., Academy of Sciencw, Geological mti-
ern North America: Geology, V. 8, no. 9, P. 454- tute, Publisher nNsuka,n p. 1-192, pls. 1-42 [in
456. Rllssianl.
101