Brown Bluff in Antarctica
February 23, 2005
Summary authors & editors: David Welch
The above photo of Brown Bluff on the Antarctic Peninsula was taken January 23, 2005. Brown Bluff is a 745 m (2,444 ft) flat-topped hill at the northern end of the Antarctic Peninsula. It gets its name from the volcanic rocks shown in this photo. They're remains of a Pleistocene volcanic eruption. Lava and other volcanic material were entombed in a lake enclosed by ice at a time when the ice caps of the Antarctic Peninsula were much thicker and more extensive than today. The vertical bluff wall at the top of the sequence shows a delta of ash and lapilli, seen close up in the fallen boulder in the foreground. Subsequent ice sheet retreat, coastal erosion, frost action and talus activity have combined to reveal the exposure and present close-up samples to visitors to this shore along the Antarctic Sound. Modern analogies are the volcanoes underneath the Vatnajokull Ice Cap in Iceland -- see tomorrow's Earth Science Picture of the Day.
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