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Unformatted text preview: siﬁed based on their surface
i. Pahoehoe (ropv) = ﬂow with smooth or ﬁlamented Pahoehoe lava flows from Kilauea (October, 1999) folds due to continued ﬂow beneath a glassy surface
ii. Aa - ﬂow with jagged, rough surface; forms from
more viscous lava that has lost its gas content. very Aa and Pahoehoe flows Image source: Hawaiian Volcano Observatory website:
http://wwwhvo.wr.usgs.gov/kilauea/ ] 22 Landforms – lava flows Lava flows from Kilauea Volcano, HI. Image source: Hawaiian Volcano Observatory
website: http://wwwhvo.wr.usgs.gov/kilauea/ ] sharp iii. ﬂows often have pahoehoe 23 Landforms – lava flows Image source: Hawaiian Volcano Observatory
website: http://wwwhvo.wr.usgs.gov/kilauea/ ] 24 8 8/27/2012 Landforms – lava flows iv. Lava tube - long tubular opening in which lava
on outside has solidiﬁed but in center it has drained
out image from the Hawaiian Volcano Observatory
website: http://wwwhvo.wr.usgs.gov/kilauea/ Skylight sin lava tube from Puu Oo Eruption of Kilauea
Volcano in Hawaii, HI. [photo by Jim Kauahikaua] Lava tube in the Galapagos Islands (Ecuador). Note the
lava flow lines. [Photo:. Barb Dutrow - LSU] Landforms – lava flows Basaltic ﬂows are classiﬁed based on their surface
forms: v. Columnar joints - ca. 5-6 sided pillars, produced by
26 Landforms – lava flows slow cooling magma Basaltic ﬂows are classiﬁed based on their surface
vi. Pillow lavas - piles of elliptical, sac-like bodies
(ca. 1m) that form when lava solidiﬁes underwater
characterized by glassy rind, commonly vesicular Contact between deposits of pillow lava (left), and tephra (right,
orange), near Aci Castello, Sicily. Note person at lower left for scale
(photo M. Fulle). (was gas charged) with crystalline interior Inset: Diver examines recently extruded lava pillow off the coast of
Kilauea volcano, Hawaii (photo R.D. Grigg).
27 9 8/27/2012 Landforms – lava flows Rhyolitic lavas erupt at 800-1000 C, very viscous
form steep-sided, bulbous deposits Newberry Crater, Oregon.
• Central pumice cone (~6,600 BP) is in left-center. Big Obsidian flo...
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- Fall '09