2006 VOL. 59(3-4)

230 THE FLORIDA ANTHROPOLOGIST

 

Explanation

0 _North Atlantic Pumic Sites

= Florida Pumice Sites Type
© Oceanic Ridge (iceland)

© Volcanic Arcs
e Oceanic Island and Alkalic
Major Ocean Current

Active Voicanoes

 

Figure 12. Distribution of Holocene volcanoes, major ocean currents and drift pumice occurrence within the Atlantic and Gulf
of Mexico Ocean basins. Distribution of volcanoes modified from Simkin and Siebert (1994). North Atlantic drift pumice sites
taken Blake (1970) and Binns (1972). Oceans currents are taken for the Hycom Consortium for data Assimilative Modeling

(URL -- oceancurrents.rsmas.miami.edu).

and ash over very short intervals of time (Walker 1981).
Volumes of Plinian fallout and pyroclastic flows can range from
less the 1 km’ to more that 3000 km’ (Fisher and Schmincke
1984). Significant volumes of pumice also can be produced by
pyroclastic deposits (including nuee ardente and block and ash
flow deposits) that flow down the flank of a volcano and travel

within valleys. Both rhyolitic Plinian and pyroclastic flow
deposits have taken place at all the locations that are candidates
for Florida drift pumice; however, none of these sites are known
to have actively producing rhyolitic material at the time (~ 2000
year B.P.) associated with the pumice. Pumice also can be
dispersed by erosion of pyroclastic deposits by heavy rainfall,