The Geology of the Rockefeller Mountains, King Edward VII Land, Antarctica Author(s): F. Alton Wade Source: Proceedings of the American Philosophical Society, Vol. 89, No. 1, Reports on Scientific Results of the United States Antarctic Service Expedition, 1939-1941 (Apr. 30, 1945), pp. 67-77 Published by: American Philosophical Society Stable URL: http://www.jstor.org/stable/985315 Accessed: 03-03-2015 04:01 UTC Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at http://www.jstor.org/page/info/about/policies/terms.jsp JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. American Philosophical Society is collaborating with JSTOR to digitize, preserve and extend access to Proceedings of the American Philosophical Society. http://www.jstor.org This content downloaded from 169.229.32.36 on Tue, 03 Mar 2015 04:01:13 UTC All use subject to JSTOR Terms and Conditions THE GEOLOGY OF THE ROCKEFELLER MOUNTAINS, KING EDWARD VII LAND, ANTARCTICA Major F. ALTON WADE, U. S. Army Senior Scientist, U. S. Antarctic Service INTRODUCTION mapped from aerial photographs taken that IN spite of the fact that threeexpeditions had same season. had theirmain bases a littlemore than 100 miles DuringByrd Antarctic Expedition II, 1933-35, away from one group of mountains in King several partieswere in the vicinityof the Rocke- Edward VII Land, practically nothing was feller Mountains during the sledging season. known of the geology of that peninsula prior Mount Helen Washingtonwas exploredin part to 1940. by the party which was under the leadershipof The discoveryof King Edward VII Land was Paul A. Siple5 and of which the author was a made by Scott 1 in 1902 whileon his firstexpedi- member. This party, homeward-boundfrom a tion to the Antarcticregions. The low range of surveytrip in Marie Byrd Land, was unable to mountains,subsequently named the Alexandra remainlong enough to completea surveyof the Mountains (fig. 1), was sightedby him as were many peaks. Mount Nilsen was visitedand as- the bare rock exposures on Scott's Nunataks. cended by a three-manparty later that same Ice conditions prevented him from making a season, but no specimenswere collected. landing. The geologicalknowledge of King Edward VII The firstand only partyto visit the mountains Land was limited,therefore, to analyses of rocks discovered by Scott was led by Lieut. K. fromScott's Nunataks, the most northernpeaks on the peninsula,and to analyses of rocks from Prestrud2 in 1911. During the same season, when the leader of the expedition,Amundsen, Mount Helen Washington,the most southerly was making his trip to the Pole, Prestrudand peak, prior to the investigationsof the United two companions sledged eastward on to the ice States AntarcticService Expedition, 1939-1941. plateau covering the greater part of Edward The regionlies between two of the better-known Land and to Scott's Nunataks, which they and geologicallydifferent regions of Antarctica. ascended and where they collected a few rock The mountains of the Antarctic Horst which specimens. borderthe Ross Shelf Ice on the west and south had been explored The moresoutherly group of mountainson the by membersof several British expeditionsand of the two peninsula was discoveredby Admiral Byrd 3 on Byrd Expeditions. January27, 1929, while on his firstexploratory The westernportion of the Edsel Ford Mountains flightin Antarctica,and was subsequentlynamed in Marie Byrd Land, which lies to the east of by him forJohn D. Rockefeller,Jr. (figs.2, 3). King Edward VII Land, was exploredin 1934 by An attemptto explorethese mountains was made Siple and Wade,6and the plans forthe U. S. A. S. by Byrd's second-in-command,L. M. Gould, Expeditioncalled fora continuationof the work later in the same season. His survey was begun by them. prematurelyended afterhe had visited only one According to David,7 the geology of the peak, Mount Helen Washington,when disaster, Antarctic Horst region is as follows:, pre- resultingin the loss of a plane, overtook his Cambrian gneisses, schists, limestones, and party.4 The RockefellerMountains were first graywackes compose the basement complex. This is overlain by a great series of nearly 1 Scott, R. F. The voyage of the "Discovery" 1: 183. London, 1905. 5 Byrd, R. E., op. cit., 347. 2 Prestruid,K. Eastern sledge journey. In: Amundsen, 6Wade, F. A. Petrologicand structuralrelations of the R., The South Pole 2: 204-261. London, 1913. Edsel Ford Range, Marie Byrd Land, to other Antarctic 3 Byrd, R. E. Little America, 124-125. New York, mountains. Bull. Geol. Soc. America 48: 1387-1395, 1937. 1930. 7David, T. W. E. Antarctica and some of its problems. 4Byrd, R. E., op. cit., chap. 8. Geog. Jour. 43: 624-626, 1914. PROCEEDINGS OF THE AMERICAN PHILOSOPHICAL SOCIETY, VOL. 89, NO. 1, APRIL, 1945 67 This content downloaded from 169.229.32.36 on Tue, 03 Mar 2015 04:01:13 UTC All use subject to JSTOR Terms and Conditions 68 F. ALTON WADE -1550 w. |~~~~~~ _ _<X // LM LA \ORCE _______ \_ - ROCKEFELLER ,_~~~~~~~~~~~~~~~~~~~~~~MXtV rRAUtC#t __- \_ =-_ __ - -ROSS SHELF ICE A-lAKO GEOLOGICAL MAP = = _ KING EDWARD VII LAND |=_ ANTARCTICA SCALE 'GEOGRAPHICAL MILES _ _ m _ i v .E.J ACIDIC INTRUSIVES F- TLOW STRUCTURE METAMORPHOSEDSEDIMENTS SCHISTOSITY A 55 OW MAP 1. This content downloaded from 169.229.32.36 on Tue, 03 Mar 2015 04:01:13 UTC All use subject to JSTOR Terms and Conditions GEOLOGY OF THE ROCKEFELLER MOUNTAINS 69 flat-lyingPaleozoic and early Mesozoic sand- igneous intrusivesto be of the acidic type, high stones, arkoses, and shales. Near the close of in sodium and potassium,with the plagioclases the Mesozoic this region was subjected to a exhibitingnio zoning. From his investigations period of block-faulting. The Antarctic Horst in 1934 the author10 concluded that the sequence was formedat that time. A period of volcanic of events in the Edsel Ford Mountains was as activityaccompanied and followedthese tectonic follows: "deposition of a great series of arkosic disturbances and is even continuing today. sandstonesand shales on the pre-Cambrianbase- There is no evidence of Antarctandeanfolds in ment rocks,close foldingof this sedimentaryse- this region. The petrographicinvestigations of ries accompanied and followed by deep-seated Prior,8 Stewart,9 and others have shown the igneousintrusion of acidic magma,a long period of erosion,glaciation and the extrusionof olivine 8 Prior, G. T. Report on the rock-specimens[etc.]. NationalAntarctic Exped. 1901-1904,Nat. Hist. 1, Geol.: fourchites." The intrusivesdiffer from those to 101-140,1907. the west and south in that the plagioclases 9 Stewart,Duncan, Jr. A contributionto Antarctic petrography.Jour. Geol. 42: 550, 1934. 10 Wade,F. A., op. cit., 1391-1392. Officialphotograph, U. S. AntarcticService FIG. 1. The AlexandraMountains, King EdwardVII Land; lookingsoutheastward along the northeastcoast ofthe peninsula. This content downloaded from 169.229.32.36 on Tue, 03 Mar 2015 04:01:13 UTC All use subject to JSTOR Terms and Conditions 70 F. ALTON WADE Officialphotograph, U. S. AntarcticService FIG. 2. The southerngroup of the RockefellerMountains; looking southwestward. MounitTennant MountHelen Washington MountFranklin MountGould MountSchlossbach MountBreckenridge MountPaterson MountNilsen exhibit well-developed zoning, a characteristic FIELD OPERATIONS of Palmer Land whichlie some of the intrusives On February8, 1940,an exploratoryflight was miles to the east. 1500 made over Edward VII Land, at whichtime the and examined the Schetelig"1 investigated author was enabled to examine the regionas a by Prestrud from Scott's rocks brought back whole. Later the entirecoast line of the pen- 12 withthose Nunataks, and Stewart did likewise insula and the two mountainranges were photo- fromMount broughtback by Gould and Wade graphed fromthe air by Charles Shirley,C.P., Both were of the opinion Helen Washington. U.S.N., the officialWest Base photographer. Edward VII Land intrusiveshave that the King The picturesthus obtained were of great assist- AntarcticHorst. close affinitieswith those of the ance in layingplans forthe fieldprogram. of Mount From his rathercursory examination On November25, 1940, the party,comprising Helen Washingtonthe authorwas of the opinion two men and a singleteam of six dogs, leftWest that the intrusives exhibited there closely Base forKing Edward VI I Land. Dr. RussellG. east resembledthe ones he had examinedto the Frazier, expedition physician and surgeon,ac- in the Edsel Ford Mountains. companiedthe author. The plan was to proceed to the RockefellerMountains and there survey 11Schetelig, J. Reporton rock-specimenscollected on the peaks composing that group. With only Skrifter Roald Amundsen's South Pole expedition. seven weeks' time available forthis operation,it Vidensk.-Selsk.Kristiania 1915, Mat.-Naturv.Ki., no. 4: 1-32, 1915. would not be possible forthe party to extendits 12 Stewart,Duncan, Jr., op. cit. itineraryto includethe Alexandra Mountains,if This content downloaded from 169.229.32.36 on Tue, 03 Mar 2015 04:01:13 UTC All use subject to JSTOR Terms and Conditions GEOLOGY OF THE ROCKEFELLER MOUNTAINS 71 dog-teamtransportation were relied upon alone. PHYSIOGRAPHY It was planned, therefore,that the Beechcraft The exposed portion of the Rockefeller plane should be flownto the Rockefellersduring Mountains occupies an area approximately20 the timewhen the partywas in that region,pick milessquare. As comparedwith such Antarctic up the author and transporthim to the heartof ranges as the Queen Maud or the Edsel Ford, the Alexandras, where he could hastily survey they are not a particularly impressive sight. those peaks in a few days' time and then be re- The black and pink peaks of the southerngroup turnedto complete the work in the Rockefeller (fig.