The Ohio State University Research Foundation Report 825-1-Pt

THE OHIO STATE UNIVERSITY RESEARCH FOUNDATION 1314 KINNEAR ROAD COLUMBUS 12, OHIO USHC-IGY ANTARCTIC GLACIOLOGICAL DATA FIELD WORK 1958 AND 1959 (The Petrography of Some Rocks From Marie Byrd Land, Antarctica) Report 825-2-Part VIII IGJf Project No. if.10 NSF Grant No. Y/k.U0/2&5 V. H. Anderson September i960 USNC-IGY ANTARCTIC GLACIOLOGICAL DATA Report Number 2: Field Work 1958-59 Part VIII THE PETROGRAPHY OF SOME ROCKS FROM MARIE BYRD LAND, ANTARCTICA by V. H. ANDERSON The Ohio State University- Research Foundation Columbus 12, Ohio Project 825, Report No. 2, Part VIII Submitted to the U. 8. National Committee for the IGY National Academy of Sciences, in partial fulfillment of IGY Project Number J+.10 - NSF Grant No. Y/lf.lO/285 September i960 Bock specimens tram. newly-^sc©¥ered •nantain Masses and nunataks in ffarie Ejyrd land, Antarctica, are described. FOOT chemLcai analyses of ¥olasyiie rocdts frai 1ft. Dnkahe are presented- The volcanic Identified, as oUgpclase aodesite, reflect a fflargl^al-contlmental ren.ce, typical of the drcum-Baelfic Pet.rr>grapMc, llthologic^ ass£L structural evidence suggest that the Sentinel MbimtalBS straetare can be extended for about 200 miles sootli westimrd, to Mt. Jcims and Ifi;. Siting. Detailed pet:rograpMc descriptions of 80 thin sectioDS are presented. il CONTENTS Page Introduction 1 Mt. Takahe I Megascopic description 6 Microscopic description 6 Chemical character of four volcanic rocks 6 Similar rock types in the area vest of Mt. Takahe 7 Sentinel Mountains JX> Fisher Nunatak (SF Series) 20 Larson Nunatak (SL, S3, Sk Series) 21 Mt, Johns (J Series) 21 Mt. Eying (E Series) 22 Conclusion 22 References cited 2J Appendix I. Petrographic description of samples from Mt. T&kahe Appendix II. Peteographic descriptions of samples from Sentinel Mountains, Mt. Johns, and Mt* Ewing iii LIST OF FIGURES Figure Page 1 Index map of Marie Byrd Land, West Antarctica, 2 2 Traverse vehicle approaching Mt* Takahe. k 3 Volcanic neck and small caldera on Mt. Takahe; Crary Mountains in background. k k Close-up of volcanic neck on Mt. Takahe. 5 5 Parasitic cinder cone on Mt. Takahe. 5 6 Photomicrograph, sample T-12, syenite from Mt. Bakahe. 9 7 Texfeural variations of cinder cone specimen from Mt. Takahe, 9 8 Photomicrograph, sample T**k, oligoclase andesite from Mt. Takahe. 9 9 Photomicrograph, sample T-B, oligoclase andesite flraw Mt. Takahe. 10 10 Photomicrograph, sample T*2, oligoclase andesite from Mt. Takahe. 10 H Photomicrograph, sample T-l, oligoclase andesite from Mt. Takahe. 10 12 Photomicrograph, sample T«C, oligoclase andesite ftom Mt. Takahe. H 13 Photomicrograph, sample T-D, blackish-brown glass from Mt. Takahe. 11 1^ Toney Mountain as seen from the cinder cone locality on Mt. Takahe. 24 15 Peaks of the Kohler Range—Mt. Takahe in right foreground. 24 16 View of part of the Sentinel Range 25 17 Summit ridge of Fisher limatak, looking eastward toward the Sentinel Range. 25 18 View of Mt. Johns. 26 19 View of Mt. Ewing 26 iv LIST OF TABLES Table Page 1 Summary of major features of some mountains In Marie Byrd Land, West Antarctica• 5 2 Chemical analysis, norm, and C.I.F.W, classifi cation of sample Takahe A* 12 3 Chemical analysis, norm, and C.X.F.W. classifi cation of sample Takahe B. 13 k Chemical analysis, norm, and C.I.P.W. classifl cation of sample Takahe C. Ik 5 Chemical analysis, norm, and C•I.f.W, classifi cation of sample Takahe D. 15 6 Average chemical analysis, norm, and C.I.P.W. classification of samples Takahe A, B, C, and D» 16 7 Analogues of Takahe Lavas 17 8 Comparisons of chemical analyses of average plateau basalts and olivine "basalts nith the average of the Takahe analyses. 18 9 Comparison of the average of the Takahe analyses with an average Hawaiian oligioclase andesite. 19 The Petrography of Some Rocks from Marie Byrd Land, Antarctica by V. H* Anderson INTRODUCTION The Byrd Station Traverse party of 1957-1958 collected rock speci mens from several mountains and nunataks while conducting glaciologica! investigations in the interior of Marie Byrd Land, Antarctica (Fig. l). Considered in this report are the occurrence, petrography, and geological significance of the specimens collected from Mt. Takahe, Mt. Johns, Mt* Effing, and some nunataks located a few miles west of the Sentinel Range. The microscopic petrographic descriptions are given in Appendix I and II, A summary of the major features of these mountains is given in Table I. An expression of gratitude is directed to Dr. R, P. Goldthwait, Professor of Geology at The Ohio State University and Director of the IGY Glaciological Data Reduction Center atfflie Ohio State University Research Foundation. Valuable suggestions, criticism, and guidance were given "by Dr. R* S. Houston and Dr. R. B. Parker, members of the faculty of the Department of Geology, University of Wyoming. Sincere thanks are also extended to Dr. S. H. Knight, Chairman of the Department of Geology, University of Wyoming, for authorizing the use of the facilities of the Geology Department, ME. TAKAHE Mt. Takaiie, 76°l6.V S., 1120lV W., rises to an elevation of 3,480 meters, 2,170 meters above the surface of the surrounding ice sheet (Figs. 1 and 2). It is a low, broad shield volcano, probably of fairly recent origin, and is almost completely covered by glacier ice and snow. At the top of Mt* Takahe is a snow-covered caldera, 70 maters in diameter; a volcanic neck 10 meters in diameter and 15 meters high occurs in the central part (Figs. 3 *&& **•)• Specimens were collected from a parasitic cinder cone (Fig. 5) &®& a volcanic neck at the base of the southwest flank of Mt, Takahe. The cinder cone is broad, about 100 meters in diameter, and subdued. Most of the samples from the cinder cone were collected from scree and rubble piles, as only one or two partially consolidated ridges of rock were exposed. In both areas, plutonic rocks (Fig. 6), presumably incorporated fragments, were observed and collected. Fig. 1. Index nap. 43 ft) •t-i O CD o o ft) ft) t-* 10 O •T-t U c to > n( ^ a o ^ ft) i 3 43 u —« 10 rt Of 4J C *H (I) «-4 43 43 1-4 CO rt 6 43 > tO &"d rt *-* 43 1 e2 s 43 o of T5 &. ^ U CL o u 10 i rt to to •-* ft) r«4 to O ft) ft) ft) . to 43 43 43 o> D X5 w 10 •<-• d 43 ft) ft) C O a C tO u 43 •-* i u o 8iS ft) o o Of ft) p. 3 W O *-* u to d 10 u > to &i 4 3 %4 4 3 I U tO M CO 0) U ft) d |43 O ^ 43 o -4 ft) u x: c u * ft) ft) U ft) ft) ft) •«H ft) ft) * ft) 43 * ft) ft) 43 43 Kf 4 3 43 ft) ft) 43 3 —• ft) H •% •%•»-< 43 «0 > T 43 43 ft) 43 o o I ft) *4_i O ft) d ft) o d d •* o d ft) d o o o 10 id ft)o u -^ ft) tO en ^ jc o I *-4 43,~l CO P.43 D rt p rt i^ox: g ft) •-< e D; to 6 ft) ft) ft) 0) tO ft) w to tO ft) CO to ntf C a rt d ft) rt AH f-i »r-t 4J t—i ^ Ci) u —* •* ft) U ^ ft) U •* u 43 o u tO 43 O M 4J O ^ c u c to o .^ o j j •*-« .«M a. u 4J . ^ . ^ +3 «,H O O 43 *-i m u j-4 o a. u o u rt rt U U U Ui a f-< tt 2.rt*• a f-i »^» rt u a, e & c a tr o a* d d 43 u ft) ft) ft) ••H d ft) o o *^ *C 10 ft) ft> 10 43 O 43 U *r* ft) ft) O A 43 43 43 •r-i 43 JQ 43 d 43 H 1H 10 o M to •rH O «*H ^ o to O N 4 ) Nl U 43 d w. rt O ft) d o x w 43 43 tO 43 0 tO O)*d ft) rt ft) «-i U ^ 2. o rt rt t-» * d s-t ft) ••-* •^ c ft) u tr t) 5 d rt d rtrt ft) x^ *H rt ft) x : to l-i to rt o (H U 43 rt 3 O) to tr o ft) o o o ta o to CO o o a to 2 * p a. o ^ U K u u J O p. w c o c o to rto > •r-4 fid o Q to •d 3 d ^ 3 53 *d +3 t/ to tn ft) o 4J M 3 43 • 1A i n •^* CT; CJ 43 C O O O o t^- GO ON o a o co O\ to to CD rt *-i c rt d ft) ft) ft) 43 d ft) d to rt •-* ft) IM C o u cr. ••-• —> ft) ft) a ft) rt to oc Fig, 2. Traverse vehicle approaching Mt, Takahe, Fig. 3. Volcanic neck and small caldera on Mt. Takahe; Crary Mountains in background. Fig. k. Close-up of volcanic neck on Mt. Takahe. • \ • Pig. 5- Parasitic cinder cone on Mt. Takahe. Megascopic Description Hie rocks from the cinder cone are dark gray, vesicular andesites. Most are scoriaceous and consist of spherical vesicles which raoge from less than one to five millimeters in diameter.

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