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d . Re lat ion to other units Overlies Her itage Range lower group conformably Overlain conformab ly by Whiteout Conglomerate e . Evidence for age "A quartz ite bed in the south -wes tern foothills of the Sentinel Range yielded what has been ident ified by 3 paleontol ogists as probably an incomplete orthoconic cephalopod . Dr. R. Flower studied the specimen and concluded it was probably a cephalopod but that it could not be identified beyond probab ly be long ing to the order Mlchelinocerat ida , which ranges from early Ordovician to Trias s ic . It was his opinion that th is specimen , if a fos s il , was no younger than Permian. " ( Craddock and others , 163) .Deception Is land volcanics 1. Fira t published use (by u.s. geolog ist ) Halpern , M. Preliminary Field studies of Ch ilean bases in North Antarct ic Peninsula : GSA Spec . Paper 68 , p . 189 -190 , 196 1 . 2 . Definit ion "The dominant lithology and geologic age of outcrops adjacent to the Chilean bases is as follows : Base Pedro Aguirre Cerda ( Decept ion Is land ) - Recent volcanics . " (Halpern , p . 189 ) 3. Type section a. Locat ion Base Pedro Aguirre Cerda on Decept ion Is land b . Evidence for age Recent . MOdern erupt ions . - 16 -
Discovery Ridge Formation 1 . First publ ished use Long , W. E. Sedimentary rocks of the Buckeye Range , Horlick Mountains , Antarctica : Science , vol. 135 , p . 319 -321 , 1962 . 2 . Definit ion "The Dis covery Ridge Formation overlies the Buckeye Tf.llite with slight disconformity and can be divided into a lower pla�· shale member about 150 ft . (46 m) thick, and an upper carbonaceous , fiss ile shale member about 400 ft . ( 122 m) thick . Numerous trails of sizeable invertebrate antmals provide the only fossil evidence from the bard s i lty shales of the lower member . " (Long, 320) 3. Type sect ion a. Location Discovery Ridge , Ohio Range , Horlick Mts . b . Thickness 545 - 640 feet c . Lithology 1 ) gray platy shale or flaggy s iltstone with .abundant trails ; 1/8-incb to l -inch bedding . 2 ) dark gray or black soft fiss ile shale , lenticular concret ions of carbonate rock to 8 inches , cone-in-cone s tructures . d. Relation to other units Overlies Buckeye Tillite with slight disconformity ; overlain by MOunt Glossopteris Formation Doumer Is land quartz diorite 1. Firat published use Scot t , K. M. Geology of the Southern Gerlacbe S traits region , Antarctica : Jour. Geo l . 73 , p . 518-529 , 196 5 . - 1 7 -
2 . Definit ion "All of Doumer Is land and part of Wieneke Is land are underlain by quartz diorite . The body is truncated on the east by the Pelteer shear zone ⢠⢠⢠⢠" (Scott , 521) 3. Type section a. Locat ion Doumer Island , Gerlache S trait region off Danco Coast b . Lithology Medium-grained , hypautomorphic â¢granular quartz diorite ; quartz , 10·23%. andes ine 38-6 1% , biotite 0·19% , hornblende 3 -20%. Inclus ions , platy flow s truc ture , transi t ional contac ts and contact metamorphism. c . Evidence for age Dover Sanda tone K·Ar age on biotite of 52 . 5 ± 2 m. y . Lead â¢alpha age of 4 5 ± 5 m . y . ( S cot t , 524 ) 1 . Firat published use Schmidt , D . L . , P. L. Wil l iams , W. H. Ne l son and J. R. Ege. Upper Precambrian and Paleozoic s trat igraphy and structure of the Neptune Range , Antarctica : USGS Prof Paper 525 -D , p . 112-119 , 196 5 . 2 . Definition "The Dover Sands tone is here named for Mount Dover , on the eastern end of the Gale Ridge ⢠⢠⢠⢠The Dover Sandstone is a tan to white thiCk-bedded to mass ive medium- co coarse-grained sandstone . Individual beds are commonly friable , although many other beds consist of well indurated quartzite . Scattered rounded pebbles of quartz occur in a few indistinct lenses of sandstone in the lower third of the section. 3. Type section a. Location Western end o f Gale Ridge , Neptune Range , Pensacola Mountains , 83° 37 ' s, 56 °48 1 w. - 18 -
b . Thickness About 4000 feet c. Lithology Tan to white , thick-bedded to mass ive , medium- to coarse grained sandstone . Bas al part of Dover cona ia ta of 1) basal white conglomerate with black pebbles ( 20 feet ) 2 ) black stained sands tone ( 10 feet ) · 3 ) upper brown iron-s tained s ands tone overlain by tan sandstone d . Relation to other units Overlies Heiser Sandstone . Overlain by Gale MUdstone . e . Evidence for age "Younger than the Cambrian Nelson Limes tone of the second sequence , but from regional cons iderations it ia probably not younger than Late Paleozoic . " (Schmidt and others , 115 ) Dufek Mass i f igneous sequence 1 . Fira t published uae Aughenbaugh , N. B. Dufek Mass if : IGY Antarct ic Sympos ium, Buenos Aires , p . 73 , 1959 . 2 . Definition "The Dufek Mass if ia a bas ic igneous complex. The rocks can be divided into two groups baaed upon color and texture ; a normal and a leucocratic series . Differentiates of both groups are found as horizontal layers wh ich resemble undeformed sedimentary beds . Sh illered pyroxenes and unzoned plagioclaaea are characteristic of these rocks . A few leucocratic layers have folding , faulting and flow features within their borders . " Aughenbaugh , 73) 3. Type section a. Location Dufek Massif in the Pen sacola Mountains . - 19 -
