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Alexander Is land sed imentary rocks 1 . F irs t publ ished use Knowles , P . H. Geology of Southern Palmer Peninsula , Antarc t ica : Am. Ph il . Soc . Proc . 89 ( 1) , p . 132-145, 1945 . 2 . De finit ion Sedimentary rock was found in s itu at latitude 72° 08 ' S . , l ong itude 68° 451 W . on the southernmost peak of Al exander I Is land . The rock consisted of un iform hor izontal s trata of compac t mudstone , graywacke , arkose , and coarse c ongl omerate . " (Knowles , 141) 3 . Type sec t ion a. Location Southernmo s t peak of Alexander I I s land b . Lithol ogy Nonmar ine mudstone , graywacke , arkose and coarse c onglomerate . 1) mud s tone - minute quartz , fe ldspar and b io t i te in a hydrous aluminum s i l icate groundmas s . 2) cong lomerate - subangular pebbles up to 1/2 " in a quar tz, fe ldspar and mica groundmass . 3) arkose - medium-grained , gray rock composed of a subangular quartz , orthoc lase and andes ine in a ferruginous ly cemented groundmas s . c . Evidence of age Nearby fos s i l localit ies sugges t a Jurass ic or Cret aceous age . Base Gab rie l Gonzalez Vide la andes i te 1 . Firs t published use Halpern , M. The geology of Base Gab rie l Gonzalez Videla, Ant arctica: Arct ic, 15 , p . 23 1-23 7 , 1962 . 2 . Definit ion "The multiple andes i te s ills or flows of Islas 'Lomnitz' and 'Dot t' are about 200 metre s th ick, Thicknes s of ind ividual sheet s is extremely difficult to de termine because of intense fracturing and poor exposures due to snow and guano cover. Where measurable shee ts are 4 t o 7 metres thick and dip s teeply s outh . " (Halpern , 232) - 1 -
3 . Type section a. Locat ion Is las "Lomnitz" and " Dott" , Base Gabriel Gonzalez Videla, on Danco Coas t , Antarctic Peninsula b . Thickness 200 m c . Lithology Dark gray, fine -grained rock ; calc ic andes ine comprises at leas t 75%. Zoning rare . Alteration of plagioclase negligible to complete . 5% quartz , 10% green to green-brown chlorite . Base Gabriel Gonzalez Videla aplite 1. Firs t published use Halpe� , M. The geology of the Base Gabriel Gonzalez Videla , Antarctica : Arctic , 15 , p. 231 -237 , 1962 . 2 . Definit ion " Throughout Is la "Lomnitz " and along the eas tern shore line of Islas "Lomnitz " and "Dott" aplite dykes ranging in width from a few mm to 0 . 5 metre intrude the andes ite sheets , porphyrit ic andes ite , and quartz diorite . " (Halpern , 234 -235 ) 3 . Type section a. Location Is la "Lomnitz" and eas t shorel ines of Is las "Lomnitz" and " Dott" off the Danco Coas t , Antarctic Peninsula. b . Lithology Pink apl ite ; microcline 55% , quartz 40% , z ircon as main accessory . c . Relation to other units Cuts all other units - 2 -
Bastion Sequence 1 . First published use Mirsky , A. Recons ideration of the "Beacon" as a strat igraphic term in Antarct ica : Polar Record Vol . XI , No . 75 , p. 765 , 1963 . 2 . Definit ion "The Bast ion Sequence includes all strata between the Carboniferous unconformity and the pos t -Jurass ic or Cretaceous unconformity at the top . All formations in this sequence are carbonaceous , and include Permian to Juras s ic plant remains . The Permian Mount Bastion Formation , the lowes t unit , dominates the sequence . The O\�rlying Trias s ic Fleming Beds and Jurass ic Carapace Beds are less well exposed . " (Mirsky , 765 ) 3 . Type sect ion a. Locat ion Southern Victoria Land b . Lithology Bast ion Sequence Carapace beds : carbonaceous sandstone or s i ltstone Fleming beds : carbonaceous s ands tone or s ilts tone Mount Bas t ion Formation : carbonaceous s andstone or s ilts tone Major unconformity : Carboniferous c . Relat ion to other units Overlies Fortress Sequence unconformably d . Evidence for age "However , characteristic elements of the contained Glossopteris flora are cons idered by J . M. Schopf ( personal communication) to be no older than Permian , ⢠⢠⢠Gunn and Warren have reported early and Middle Trias s ic plant beds at Mbunt Fleming and adjacent areas (herein called the F leming beds ) , and probable early Jurass ic plant beds at Carapace Nunatak (herein called the Carapace beds}. " (p . 372) Mirsky, A . Reconsideration of the "Beacon" as a strat igraphic term in Antarct ica : Antarctic Geology , Proc. Capetown Sympos ium, 1963 , John Wiley and Sons , p . 364-378 , 1964 . - 3 -
Beacon Sandstone 1 . First published use Hamilton , w. and Hayes , P . T . Type section of the Beacon Sands tone of Antarctica : USGS Prof. Pap . 456â¢A , p . 1 -18 , 1963 . 2 . Definit ion '�ith poss ible except ion of bas al s trat a in some parts of the region of the type section , the rocks named Beacon S ands tone by Ferrar ( 1907 ) , and so called by many others s ince , comprise a remarkably homogeneous assemblage for wh ich format ional s tatus seems more appropriate than group s tatus at least until much more is known about the rocks . We recommend that the original name Beacon Sandstone be retained and that the type locality remain the vicinity of Beacon Heights as intended by Ferrar . We recommend further that the compos ite type sect ion cons is t of the exposure of New MOuntain , West Beacon Heights , and the west s ide of Beacon Dry Valley. " (Hamilton and Hayes , 9 ) . 3 . Type section a. Locat ion Compos ite section from Beacon Heights , near Taylor Glacier west of McMurdo Sound b . Thickness about 4000 feet c . Lithology Light-colored medium- to coarse-grained s ands tone, much of it cross -bedded. Beds of fine -grained sandstone and s ilts tone are subordinate . Carbonaceous strata bearing constituents of Glossopteris flora occur high in the formation. Intrusive into the Beacon S andstone are huge s ills and inclined sheets of quartz diabas e . Three subdivis ions i n ascending order : 1) s ands tone of New Mountain 2) s ands tone of Pyramid MOuntain 3) sands tone of Finger Mountain d. Evidence for age Overl ies s trata of Devonian age "The Beacon S andstone of Carboniferous (?} , Permian, and - 4 -
early Mesozoic ( ? ) age forms a dis cont inuous cover upon much of E ast Antarctica. " (Hamilton and Hayes , 1 ) Berteaux quartz diorite 1 . First published use Knowles , P . H . Geology of the Southern Palmer Peninsula , Antarctica : Am.Phil.Soe-Proc.89 (1) , p . 141 , 1945. 2 . Definit ion 3 . Cape Berteaux is composed predominantly of a quartz diorite intruded by diabase and porphyritic basalt dikes . (Knowles , 1945) Type section a . b . c . Location Cape Berteaux Lithology Quartz diorite Relation to other units Contacts between diorite and dikes , which have an average dip of 88� s 15° B, and a strike of N 75° E , are sharp and regular with abundant contact metamorphic effects . BlaCk Thumb MOuntain ultramafic rock 1 . First published use Nichols , R. L. Bedrock geology of Marguerite Bay area , Palmer Peninsula , Antarct ica : Ronne Ant . Res . Exped . Tech . Rept . 13 , Office of Naval Research , Washington, D . c. , 60 pp., 1955 . 2 . Definition "Ultramafic roCk is found at Black Thum Mt . , Neny Is land , and perhaps on the south s ide of Neny Fjord 1 1/2 miles wes t of the terminus of Neny Glacier . " (Nichols , 49 ) - 5 -
3 . Type section a . Location Black Thumb Mountain b . Lithology Very coarse -grained (up to 1/2" ) . Almost wholly pale green uralit ic act inolitic hornblende , minor magnetite . Gabbroic gradat ions . c . Relation to other units Associated with Neny Glacier Island gabbro Brown Ridge Conglomerate 1 . Firs t published use S chmidt , D. L . , P. L. Williams , W. H. Nelson. and J. R. Eae. Upper Precambrian and Paleozoic s tratigraphy and structure of the Neptune Range , Antarctica: USGS Pro£ Paper 525-D , p . 112-119, 196 5 . 2 . Definition "The Brown Ridge Conglomerate is here named for Brown Ridge , where it is well exposed . ⢠⢠⢠"The Brown Ridge Conglomerate is characteris t ically red , poorly bedded , and poorly sorted ; however , the lower part is green in some localities . Cobbles cons ist predominantly of s ands tone , s late , and vein-quartz clas ts derived from the Patuxent Formation , but abundant limestone and fels ic volcanic clas ts are locally present. Larger clas ts are commonly 3 inches in diameter , but some are as large as boulders several feet or more in diameter . The matrix contains abundant calcite , especially near the top of the section. " ( Schmidt and others , 115) 3 . Type section a. Location 2 mi . SW of W end of Brown Ridge , Neptune Range , Pensacola MOuntains , 83° 38' S , 55° 30 1 W. b . Thickness Maximum of several thousand feet , locally changes at the rate of several hundred feet per mile. - 6 -
c . Li thology Red, al though green l ocal ly , poor ly bedded and sor ted , cobble s of s l ate , sand s tone and ve in quar tz from Patuxen t Formation , some l ime s tone and fe l s ic volcanic c las t s . Clasts commonly 3 " in calc ite matr ix. d. Relation to other units Unconformably overlies fels ic s ill and Nelson Lites tone , elsewhere Nelson Limestone and Patuxent Formation. Overlain gradationally by E lliott S andstone . e . Evidence for age "Younger than the Cambrian Nelson Limestone , but from regional cons iderations it is probably not younger than late Paleozoic . " ( Schmidt and other , 115 ) . See Neptune G�oup. Buckeye Tillite 1 . First published use Long , W. E . Sedimentary rocks of the Buckeye Range , P.orlick Mountains , Antarct ica : Science , vo l . 135 , p . 3 19 -321 , 1962 . 2 . Definition "The Buckeye Tillite ranges in thicknes s from 700 to 900 ft. ( 215 to 275 m) and is composed predoadnantly of lithified bluish grey boulder clay with several thin or lenticular depos its of bedded s ilts tone and sandstone . Exposures extend more than 20 miles ( 32 km) along the front of the Ohio Range . Boulder pavements and s triae indicate a rather cons istent movement of ice from wes t to east . Erratic& in the t illite range in s ize from sand s ize to about 20 ft . ( 6 m) in diameter . The matrix is clay , s ilt and sand-s ized material . The interbedded sandy layers probably resulted from ou�ash depos its during glacial recess ions. The age of the tillite is uncertain but spores found in interbedded shales at the top of the Buckeye Tillite suggest a Permian age. " (Long , 766 ) 3 . Type section a. Location Ohio Range, Horlick Kts. b . Thickness 700 - 900 feet - 7 -
c . Lithology Blue to green-gray mudstone matrix , 72% sed imentary pebbles , 21% igneous , 7% metamorphic , subangular , some faceted and s triated ; dark green-gray s ilts tone is the dominant pebble type . d . Relat ion to other units OVerlies Horl ick Format ion disconformably . Overlain by Discovery Ridge Formation with s light disconformity . e . Evidence for age Permian spores at top . Bunger Lake charhockite series 1 . First published use Apfel , E . T . and W. T. Huang . Charnocki te series , in Bunger Lake area , Antarct ica: GSA Bull . , 6 5 , p . 1226 -27 , 1954 . 2 . De finit ion "The charnockite series is represented by hypers thene granite , hypers thene tonal ite , and members des ignated as norite and norite charnockite , respectively . " (Apfel and Huang , 1226 ) 3 . Type section a. Location North end of Bunger Lake, Antarct ica ( 66 ° 0 7 '8 , 100°56' E ) b . Lithology 4 . Remarks Bas ic charnockites contaminated by granite ; acid and intermediate members cons is t of errat ics . Mineralogical features of petrogenic s ignificance 1 ) characterized by paucity of water 2 ) increase of FeO/MgO in the more acid members 3 ) s trong development of microperthite and m,rmekite 4) garnet occurs in hypers thene granite , augite in norite charnockites Originally a differentiated sequence of bas ic igneous intrus ions, but metamorphosed during granitization . - 8 -
