Shackleton's Last Voyage: The Story of the QuestWild, Frank
History
Shackleton's Last Voyage: The Story of the Quest
Wild, Frank
Antarctica -- Discovery and exploration -- British; Quest (Ship); Shackleton, Ernest Henry, Sir, 1874-1922
Rock fragments washed from material dredged at 19 fathoms off
Zavodovski, South Sandwich group, 20/1/22.
The sample consisted of a few grammes of rounded black pellets varying
in diameter from 1 to 5 mm. They consisted of the following:
Ten dense black glassy basalts. All appear free of olivine. Some
are crowded with minute laths of plagioclase; others contain fewer
minute laths but show a few small phenocrysts of plagioclase, or
of augite, or both.
Four dense dark-brown glassy olivine-basalts, some containing many
crystals of plagioclase, and a few crystals of olivine and augite.
The glass is crowded densely with magnetite and sometimes with
other undetermined microliths.
Four rather paler basalts with holocrystalline-porphyritic
texture. These contain very small phenocrysts of plagioclase
and sometimes of augite, in a ground mass of very minute laths
of felspar and grains of augite and magnetite. The texture of
the ground mass is intergranular. One of the specimens contained
no augite phenocrysts, but rather numerous microphenocrysts of
magnetite.
Two small fragments of pale basalt-glass, deep olive-buff in
colour. Microliths are absent in one specimen, but they are
abundant in the other and consist of small laths of plagioclase,
and minute prisms of augite and a few crystals of what is probably
olivine. The felspar laths gave extinction angles of 15°, but only
a very few measurements could be made. This material resembles
the pale patches of glass in the palagonite tuffs of Sicily and of
Kerguelen Land,[17] and a somewhat similar though darker coloured
rock has been described from Schwartzenfels Hesse as vitrophyric
basalt, and has been elegantly figured by Berwerth.[18]
ISLANDS OF THE SOUTH ATLANTIC OCEAN
GOUGH ISLAND.—_Lat. 40° S. Long. 10° W._
Gough Island lies roughly 200 miles south of the Tristan da Cunha
group. It is 8 miles long by 3 miles wide.
_Topography_
The island forms a monoclinal block with dip slopes to the west and
escarpments to the east. The highest point on the long ridge which runs
down the longer axis of the island is about 2,915 feet above sea level.
The west side of the ridge goes down in a long slope to the cliffs
bordering the sea.
The escarpments on the east side are cut by three or four glens.
The largest one, about half-way down the coast, gives access to the
interior.
The most striking feature, looking up the glen, is the great stock
of an acid intrusive rock, which rises to 2,270 feet. It can best be
described in the words of Scott:
“Shooting abruptly from the dell
Its thunder splintered pinnacle.”
_Geology_
Public-domain text, read in full here on John Shaqi.
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