Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
3 . Type section a . Evidence for age "Doubtless these rocks are Precaubrian . " (Gould , 188 ) Razorback Format ion 1 . First published use Mirsky , A . , S . B . Treves , P . E . Calkias . Stratigraphy and petrography, MOunt Gran area , southern Victoria Land , Antarct ica : Geology and Paleontology of the Antarctic , Ant . Res . Series Vol . 6 , P ⢠145 - 176 , 1965 . 2 . Definit ion "The Razorback formation crops out in the lower s lopes of Alatna Valley and at the base of MOunt Gran . It is more than 1100 feet thick at the type sect ion at MOunt Razorback and about 1300 feet th ick at the Battleship Promontory section ⢠⢠⢠⢠" (Mirsky et al , 154 ) 3 . Type section a. Location MOunt Razorback , S outh Victoria Land b . Thickness 1100 feet c. Lithology Homogeneous , white to gray , fine to medium quartz sandstone , rounded to subrounded , well-sorted . Local conglomerat ic lenses and concret ions . Cross -bedding common , feldspar rare . d . Relation to other units Overlain by Mt . Bastion Formation disconformably Red Rock Ridge Granite 1 . Firs t published use Nichols , R. L. Bedro�k geolqg y of Marguerite Bay area , Palmer - 105 -
Peninsula , Antarctica : Ronne Ant . Rea . Exped . Tech . Rept . 13 , Office of Naval ResearCh , Washington, D . C . , 60 pp . , 1955 . 2 . Definition "The Red Rock Ridge Granite ia the moat abundant rock at the western end of Red Rock Ridge . The granite in places ia filled with vuga which contain quartz , feldspar , pyrite , and other minerals ." (NiChola , SS ) 3 . Type sect ion a . Location Red Rock Ridge , Antarctic Peninsula b . Lithology Sutured granitoidal texture , SO% feldspar altered to kaolin and sericite , abundant quartz irregularly fractured and 2% altered mfica c . Relation to other units Intrudes Terra Firma Volcanics Rockefeller MOuntains leucogranite 1. Fira t published uae Gould , Laurence M. Some Geographical Results of the tyrcl Antarctic Expedition : Geog . Rev. 21 , p . 177 -200 , 1931 . 2 . Definition " ⢠⢠⢠the min body of rock ia a coarse-grained pink granite . A few pegmatite dikes and veins have intruded the older granite . In places it ia also shot through with dikes of gray granite and pink granite di ffering from the min mea primrily in structure only. " (Gould , 179 ) . "The greater part of the exposed portions of the Rockefeller Mountains ia highly acidic , intrusive , igneous rock which appears to au�ound a remnant of pre -exis ting metamorphosed sediments . " Wade , F . Alton Geology of the Rockefeller MOuntains : Am. Phil. Soc. - Proc . 89 , p . 67 -77 , 1945 . - 106 -
3 . Type sect ion a. Location North group of Rockefeller MOuntains and many peaks of south group. b . Litho logy Granite , medium- to coarse -grained , l ocal ly porphyr itic . It is high in Na and K and low in mafica ; plagioclase shows well developed zoning . c . Relation to other units Intruded along pre -exis ting s tructural trends , the granite occupies a series of previous ly folded and metamorphosed sedimentary rocks . d . Evidence for age Structural and petrolog ic resemblance to rocks of Edsel Ford Ranges . Host metamorphic& correlate tentat ively with roCks dated as "other than pre·Camrian" in the Ford Ranges . Radiametrec dates suggest a Cre taceous age . Rockefeller MOuntains metamorph ic rocks 1. First published use Wade , F . Alton. Geology of the Rockefeller MOuntains : Am. Phil . Soc . Proc . 89 , p . 67 -7 7 , 1945 . 2 . Definit ion "The sediments were apparently folded and metamorphosed prior to the intrus ion of the granit ic batholith . The original metamorphism was probab ly of the dynamothermal type produced during orogenic deformation that resulted in fold mountains . Metamorphism was continued and intens ified through contact When the batholith was intruded . The fold axes have a (northwes t-soutb east) trend and the intruded beds in the area examined dip from 25° to 45° to the southwest . " (Wade , 73 ) 3 . Type section a. Location MOunt Nilsen , MOunt Breckenridge , West Nilsen Ridge , MOunt Franklin of the Rockefeller MOuntains . - 107 -