Lexicon of Antarctic Stratigraphic Names: Introduced by Members of United States Expeditions (1972)

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2 . Definit ion "Beneath the sands tone of Pyramid Mountain is a section composed largely of yellowish-gr ef cros sbedded coarse-grained sands tone , whiCh weathers to s lopes and ledges and which we will call the s ands tone of New !buntain. The name is derived from the peak vest of Windy Gully ." (Hamilton and Hayes , 11) 3. 'fype section a . Location Lower north s lope of Wes t Beacon Heights , Victoria Land b . Thickness About 1850 feet c . Lithology Yellow-gra y , cross -bedded , coarse -grained sands tone with interbedded platy , finer , micaceous sands tone , g�een argillite and pebble conglomerate . Sandstone is primarily •1uartz , but some potas s ic feldspar is present in the lover part of the unit. d . Relation to other units OVerlain by Pyramid Mountain Sandstone OVerlies Terra Cotta Mountain Member disconformably 4 . Remarks Member of Beacon S andstone . See Memer Al , wh ich is included in this unit . Parad i se Bay quartz diorite 1 . First published use Scott , K. � Geology of the southern GerlaChe Strait region , Antarctica : Jour . Geol . 73 , p . 518 -529 , 196 5 . 2 . Definit ion "Quartz diorite coq.oses moat of the exposures bordering Paradise Bay on the north , cropping out on the is lands support ing Base Gabriel - 96 -

Gonzalez Videla , Mol ina Po int , the nor thern end of Penguin Island , and in coastal exposures between the Base and Canelo Point . " (Scott , 523) 3 . Type sect ion a. Location Parad ise Bay, Ger lache S traits region off Danco Goast b . Lithology Rock is one half myrmekit ic intergrowths of ol igoc lase , and andea ine with quartz ; remainder saua seritized sad ie andes ine , quar tz and or thoc lase , l ight green hornblende . l�pauto­ morph ic-granular texture . c . Re lation to other units Intrudes Gerlache Strai ts volcanics 4 . Synonyms or closely re lated names See Base Gabr ie l Gonzalez Videla quartz d ior ite Patuxent Format ion 1 . F irs t pub l ished use Schmid t , D . L . , A . B . Ford , J . H. Dover , and R . D . Brown . Prel iminary geology and struc ture of the Patuxent Mountains : Polar Record 1 1 ( 7 5) , p . 760 , 196 3 . 2 . Definition "The oldest and most widespread rocks of three thick s ed imentary units making up the Patuxent Mountains are intense ly folded impure sandstone and s late . The greyish-green sandstone and s late are rhythmica l ly interbedded and have charac ter is tic s of sed iments depos ited by turbidity currents in moderate ly deep water . The beds are d isharmonical ly folded about nor th- trend ing axes which general ly plunge less than 10 ° to the nor th or south o::." approxi .. mately ver t ical axial planes ; an axial plane c leavage is we l l developed . " (Schmidt and others , 760) 3 . Type sect ion a . Location Highest nunatak in eas tern Patuxent Mountains (6i• 0 W , 85° S) - 9 7 -

b . Thickness Tens of thous ands of feet ( at leas t 900 m at type section) c . Lithology Interbedded argillaceous sands tone and s late , typically graf• green , well -bedded and well-indurated , some graded bedding , load casts , poorly sorted , angular to subrounded quartz and feldspar in a clay and mica matrix wi th carbonattt cement . d . Relat ion to other units OVerlain by Beacon Sandstone with angular discordance ( Schmidt and others , 760) . OVerlain unconformably by Nelson Limestone in Neptune Range e . Evidence for age Deformation presumably older than Devonian ( Schmidt and others , 760) . The Patuxent Format ion is probably of late Precambrian age , • • • S chmidt , D . L . P . L. Will iams , W . H . Ne lson and. J .R . Ege. Upper Precambrian and Paleozoic stratigraphy and s tructure of the Neptune Range , Antarct ica : USGS Prof Paper 525-D , p . 112·119 , 1965 . Patuxent Mountains carbonate rock 1 . Firs t published use Schmidt , D . L . , A . B . Ford , J . H. Dover and R. D . Brown . F·reliminary geology and structure of the Patuxent Mountains : Polar Record 11( 75 ) , p . 760 , 1963 . 2 . Definit ion "A carbonate unit is Dllch les s widely exposed and cons is ts of pre­ dominantly mass ive to thin-bedded l imes tone containing minor calcarenet ic , oolit ic , black carbonaceous and arg illaceous interbeds . The carbonate rocks were probably depos ited in moderately shallow water . Bedding in the unit dips homoclinal ly 3 5 ° to 65° south and strikes approximately normal to the trend of the fold axes of the sandstone -slate unit , ( Patuxent Format ion) . " (Schmidt and others , p . 760 ) . 3 . Type sect ion a. Locat ion Patuxent Mountains (64° W , 85° S ) - 9 8 -

b . Thickness 550 feet plus c . Lithology White to gr ay, mass ive to thin-bedded limestone and dolomite with beds of calcarenite , oolite , algal pe lite , carbonaceous dolomite or carbonaceous limestone , some recrys tallization and stylolites with ferruginous res idues . d . Relation to other units Overlain by Beacon Sandstone with angular unconformity. e . Evidence for age Deformation is older than Devonian (Schmidt and others , p . 760 ) 4 . Remarks Name obsolete. See Nelson Limestone . Patuxent MOuntains diabase 1 . Firs t published use Schmidt , D . L . , A. B. Ford , J . H. Dover , and R. D . Brown. Prel iminary geology and structure of the Patuxent MDuntaina : Polar Record 11( 7 5 ) , p . 760 , 1963 . 2 . Definition " Brecciated and altered diabase ( ?) intruded the sandstone -alate unit probably prior to late Paleozoic . " ( Schmidt and others , p . 760 ) "The diabaa ic rock is intensely altered , and the adjacent wall rock is s ilicified , hornfelsed and metaaomat ically altered for about a hundred metres from the contact . " ( 281) Schmidt , D . L. , J . H. Dover , A. B . Ford , and R . D • . Brown. Geology of the Patuxent MDuntaina : Antarctic Geology , Proc . Capetown Sympoa i� 1963 , John Wiley and Sons , p. 276 -283 , 1964 . 3 . Type section a . Location Patuxent MDuntaina ( 64° W , 85° S ) - 99 -

b . Thickness 5 - 1000 fee t in the Ne ptune Range c . Re lat ion to o ther units Intrudes Patuxent Format ion d . Evidence for age Tentative ly late Precambr ian ( 1 16 ) Schmid t , D . L . , P . L . Wi l l iams , W . H . Ne lson and J . R . Ege . Upper Precambr ian and Paleozoic stratigraphy and s truc ture of the Neptune Range , Antarct ica : USGS Pro f . Paper 52 5-D , p . 1 12- 1 1 9 , 196 5 . Patuxent Mountains lamprophyre 1 . F irst pub l i shed use Schmid t , D . L . , A . B . Ford , J . H . Dover , R . D . Brown . Pre l �inary geology and s truc ture of the Patuxent Mountains : Polar Record 1 1 ( 7 5) , p . 760 , 1 963 . 2 . De f inition "Black basa l t ic to lamprophyr ic dykes intruded the sands tone­ s l ate . uni t probably at shal low depth as is sugges ted by pronounced viscous flow s truc tures , l ocal palagon i t ic contac ts , and essent ial ly unal tered wal l rocks . The ir intrus ion may be as late as Cenozo ic . " (Schmidt and others , p . 760) 3 . Type sec t ion a. Location Patuxent Mountains (64 ° W, 85 ° S) b . Lithol ogy B iot ite- lamprophyre s �ilar to monchiquite , o l ivine phenocrys ts in a goundmass of b iotite , pyroxene , nephe l ine and magnet ite , some ol ivine al tered to serpent ine and carbonate , inc lus ions of b io t i te , c l inopyroxene , garnet , apatite , xenol iths of dunite per idotite and leucocratic gabbroic gneiss . Schmid t , D . L . , J . H . Dover , A. B . Ford and R . D . Brown . Geol ogy of the Patuxent Mountaina : Antarct ic Geology Proc . Capetown Sympos ium, 1963 , John Wiley and Sons , p . 276- 283 , 1964 . - 100 -

c . Re lation to other units Intrude s Patuxent Format ion d . Evidence for age Pecora Formation Their intrusion may be as late as Cenozoic (Schmid t and others , p . 760) 1 . First publ ished use Wil l iams , P. L. Petrology of Upper Precambr ian and Paleozoic sand stone s in the Pensacola Mountains , Antarc ticu : Jour . Sed . Pet . 39 , p . 1455- 146 5 , 1 96 9 . 2 . Definition ·�os s i l i ferous sandstone , s i l ts tone , and shale of Permian age occur in the southern Forrestal Range and at the Pecora Escarpment south of the Patuxent Range • • • The success ion of beds at the Pecora Escarpment is only about 1 10 m. thick, but it is wel l-exposed , flat­ lying , and relative ly unme tamorphosed . Therefore , the Pecora Escarp­ ment (83°3 7 1 S , 6 8°3 1 1 W) is designated the type sec tion , an� the unit i s here named the Pecora Formation . " (Wi l l iams , 146 2) 3 . Type sect ion a. Locat ion Pecora Escarpment , Pensacola Mountains (85°3 7 1 S , 6 8°31 1 W) b . Thicknes s 1 10 - 200 me ters p lus c . Lithology Ledge- forming , gray , tan-weather ing , very fine- to fine­ grained , rarely med ium-grained , thin-bedded and thinly cross- bedded sand s tone . Carbonaceous interbeds with Glossopter is . Sandstone s are chiefly graywacke& . d . Re lat ion to other units Over l ies Gale Mudstone e . Evidence for age Glossopter is flora of late Permi an age - 101 -

4 . Remarks Pecora Formation correlates wi th Weller Sands tone in Rosa Sea area , Mount Glossopteris Formation in Horlick Mountains , Polaratar Format ion in E llsworth Mountains and Theron and Whichaway Formations in Coates Land (Williams , 1463 ) . Pecten Glaciat ion depos ita 1 . Firat published use Ni chola , R . L . Mult iple glaciat ion in the Wright Valley, MCMurdo Sound , Antarct ica : Abstracts , Tenth Pacific S cience Congress of Pac . Sci . As s oc . , p. 3 17 , 196 1 . 2 . De finit ion "The type depos it of the Pecten Glaciation, s tratified gravels containing a high percentage of pecten shells , is on the floor of Wright Valley approximately twenty-five miles from MCMUrdo Sound in a gully cut by a stream which came from Bull Pass . " (Nichqla , 317 ) 3 . Type sect ion a. Location Wright Valley , 25 miles from MCMurdo Sound , Victc•ria Land b . Relation to other units Younger than Loop and Trilogy Glaciat ions c . Evidence for age "Carbon-14 analys is proves that the shells are more than 35 , 000 years old. " (Nichola , 317 ) Polara tar Format ion 1 . Fira t published use Craddock , c. , J . J . Ander aon . and G . F . Webera . Geo logic Outl ine of the E llsworth Mountains : Antarct ic Geology , Proc . Capetown Symposium, 1963 , John Wiley and Sons , p. 155-170 , 1964 . - 102 -

2 . Definit ion "The youDgeat known bedrock formtion in the mountains crops out only in the northeas tern Sentine l Range . Its dis t inct beddiDg , dark grey colour and large folds make it easy to identify in the field or on aerial photographs . The s tructure is complex and no complete stratigraphic section has been found . Good sect ions are present at Polaratar Peak and in the surrounding area , and the name Polara tar Formation ia proposed for this unit . (Craddock and others , 165 ) 3 . Type section a . Location Polara tar Peak , Sent inel Range , E llsworth MOuntains b . Thickness about 3000 feet c . Lithology Interbedded a late , argillite , impure quartzite and greywacke . Few 30" bentonit ic beds , laminar to thin bedding but formation weathers to feet-thick units , 3-foot croaa -beddiDg and current ripples , penecontemporaneous folds , medium to dark grey fresh ; l ight grey, brown , dusky red , fairly well sorted , angular volcanic rock fragments , quartz and feldspar in chlorite and sericite matrix , poorly preserved fos sils . d . Relation to other units Overlies Whiteout Conglomerate (poss ibly diaconformbly ) e . Evidence for age Glossopteris flora suggests Permian age Pyramid MOuntain sandstone 1 . Firat published use Hamilton , W . and P . T. Hayes . Type section of the Beacon Sandstone of Antar�tica : USGS Prof Paper 456 •A , p . 1 -18 , 1963 . 2 . Definition '�e call this cliff-forming sands tone the sands tone of Pyramid MOuntains , the name coming from a peak , in the type area , on whose cliffs it ia well exposed . I f addit ional fieldwork shows that this unit - 103 -