Geological Map of Adelaide Island

Home , Adelaide Island, Avian Island, Graham Land, Lagoon Island, Reptile Ridge

69°00' W 68°40' 68°20' 68°00' 67°40' 67°20' W

Sillard 6To Islands Scale: 1:200 000 kilometres Cape Mascart 6Ga-Gd 0 5 10

0 5 miles 6To

66°40' S E 66°40' S G 1:200 000 Scale A S S 6 To A Mount 4 Vélain P Geological Map of Adelaide Island,

H BAS GEOMAP 2 Series, Sheet 2, Edition 1 6Ga C

U 4 Geological interpretation and map compilation by T.R. Riley, M.J. Flowerdew and C.E. Haselwimmer. Geological cross section compiled by B T.R. Riley and C.E. Haselwimmer. Data preparation, digital cartography, design, and layout by C.E. Haselwimmer. Geological mapping and digital map production was undertaken as part of the BAS Environmental Change and Evolution (ECE) programme.

6Ga Base map data for coastlines, rock outcrops, and ice shelves from the Antarctic Digital Database. The Antarctic Digital Database is copyright 4 © 1993-2006 Scientiﬁc Committee on Antarctic Research.

66°50' 66°50' Preferred reference for map: LIARD RILEY, T.R., FLOWERDEW, M.J. and HASELWIMMER, C.E. 2011. Geological Map of Adelaide Island, Graham Land (1:200 000 scale). BAS 6 ISLAND GEOMAP 2 Series, sheet 2, British Antarctic Survey, Cambridge, UK. Projection: WGS 1984 Antarctic Polar Stereographic, Central Meridian: 68.15°W, Spheroid: WGS84. Latitude of true scale: 71°S.

6Ga Published by BRITISH ANTARCTIC SURVEY, High Cross, Madingley Road, Cambridge, CB3 0ET, United Kingdom. This geological map is copyright © British Antarctic Survey, Natural Environment Research Council, 2011. All rights reserved. 6 6Ga Ga

s d n a 4 l GEOLOGICAL LEGEND s 6To I t Geological units are coloured as dark and light tints representing exposed (mountains or

n nunataks) or inferred geology (under ice or snow ) a n Hanusse h a u c n B Bay PERIOD EPOCH/AGE PLUTONIC, VOLCANIC AND SEDIMENTARY ROCKS 6Ga o 6Gd-Ga

Adelaide Island Intrusive Suite 67°00' m 67°00' Eocene Typically granodiorite - gabbro hybrid plutons which outcrop widely on the Wright Peninsula and the Mount Gaudry-Mount Mangin region. Pluton compositions become increasingly silicic further north with quartz monzonite and tonalite more abundant. An emplacement age in the range, 45 - 52 Ma, is favoured 4 (Pankhurst, 1982; Grifﬁths & Oglethorpe, 1998; Riley et al., in press). Associated with relatively minor dolerite dyke intrusion. D-diorite; G-granite; Ga-gabbro; 6 Gd-granodiorite; QD-quartz diorite; QM-quartz monzonite; To-tonalite. d

6 PALEOGENE Reptile Ridge Formation To Rhyolitic ignimbrites, crystal- and crystal-lithic-tuffs, up to 400 m in thickness. Outcrop extent is restricted to Reptile Ridge, Webb Island, Killingbeck Island and e Piñero Island. Eruption age of 67.6 ± 0.6 Ma (Riley et al., in press). Paleocene 5 Mount Liotard Formation 6Gd-Ga Bond Nunatak Formation i Basaltic volcanic breccias, aphanitic basaltic-andesite lavas Up to 1800m of basaltic andesite lavas, hyaloclastites and breccias. 6 6To Gd-Ga and basaltic pillow lavas (at Sighing Peak). Interbedded with Interbedded sedimentary rocks are rare or typically absent. The coarse-grained, immature sandstones and cobble/boulder main area of outcrop is the Mount Liotard area, Carvajal area and conglomerates. Outcrop through central Adelaide Island from Jenny Island. Probable correlative of the Bond Nunatak Formation. P Mount HANSEN Mount Vélain to Bond Nunatak and Lagoon Island. Probable An age in the range 75 - 65 Ma is likely and supported by Late 4 Reeves 6Gd-Ga ISLAND age of ~75 Ma (Grifﬁths & Oglethorpe, 1998). 3 Tertairy-age plant fossils from Cape Alexandra (Jefferson, 1980).

6Gd-Ga 6 4 Milestone Bluff Formation Bedded sedimentary, volcaniclastic and volcanic rocks exposed in the escarpments of south central Adelaide Island at Fletcher Bluff, Milestone Bluff, Window CRETACEOUS Bond 6Gd-Ga Buttress to Cape Alexandra. Dominated by cobble/boulder conglomerates and sandstones composed of immature volcanic material. Interbedded with rare Nunatak Early crystal, crystal-lithic and vitric tuffs. Belemnite, bivalve and plants fossil fragments have been located at Milestone Bluff and Window Buttress. An interbedded 6Gd-Ga silicic crystal tuff has yielded an age of 113.9 ± 2.5 Ma (Riley et al., in press). 9 2 1 4

4 A

6QD Buchia Buttress Formation 67°10' 67°10' A succession at least 400 m in thickness dominated by volcanic breccias, tuffs, volcaniclastic rocks, accompanied by interbedded coarse grained sandstones L JURASSIC Late and pebble conglometrates. Outcrops at Buchia Buttress, Sheldon Glacier area and Turner Glacier. The sandstones are locally fossiliferous (ammonite, bivalve, plant material) suggesting a Tithonian age (Thomson 1972). An age conﬁrmed by U-Pb (zircon) dating of an interbedded crystal tuff at Buchia Buttress (149.5 ±

14 U 1.6 Ma; Riley et al., in press). The Buchia Buttress Formation is overlain by basaltic andesites of the Bond Nunatak Formation. e 1 6To

Mount S Bouvier 6Gd-Ga c 6Gd

6 N 4 QD GEOLOGICAL SYMBOLS

I DAY I ISLAND Fault Bivalve fossil Plant fossil

6 6Gd-Ga N To Normal fault (tick on 1 Ammonite fossil Trace fossil E downthrow side) 11 12 14 6Ga-Gd Buchia P Bedding Belemnite fossil Buttress 70 4 WYATT

ISLAND Shambles Glacier

D OTHER SYMBOLS

6 67°20' R Gd-Ga 67°20' s Coastline Sea

H O

T h Stonehouse Bay J 4

6QM

I F M 6Ga-Gd c C c a 9 l l 8 u m Sighing Peak 6Ga-Gd M

P 6 6Ga a Ga-Gd s s

u GEOLOGICAL CROSS SECTION FROM MILESTONE BLUFF TO REPTILE RIDGE 6Ga-Gd S 6Ga-Gd (Line A-A1 drawn on the map)

4 F Mount 6Ga-Gd Mangin WRIGHT6D F W

4 6QM U Horizontal scale: 1:200 000 Vertical exaggeration x3 6Gd 6Gd-Ga 5 O 5 E Lincoln Nunatak 15 Webb Island PENINSULA6G 1 12 6Gd-Ga B R A A1 10

14 U Mount Gaudry 1 R 6 metres Gd-Ga Milestone A 5 1000 Bluff Sheldon A 67°30' 67°30' Glacier L 3 Reptile Sheldon Glacier Ridge 6Ga-Gd 6Gd 0 3 2 5 6Ga-Gd 6G 6 1 Mount 6Gd-Ga Ga-Gd 4 Reptile Ridge Mackay Point Gaudry 1 6Gd-Ga 6 5 A1 -1000 1 4? Gd-Ga 1 1 6 Ga-Gd 12 r d Rothera Point 5 j o F Turner Ryder Bay 6Gd-Ga Killingbeck 5 n 6Ga-Gd Glacier Island d a Piñero Island o u r Fletcher Lagoon Island i g Bluff Léonie Island B

1 6 4 1 Ga 12 14 3 Anchorage Island 2 74 A 6Gd Mount REFERENCES Liotard 63 6 6 33 6Gd Gd Ga Milestone 2 Bluff 6 1 15 Gd Cape Adriasola 11 Dewar, G.J. 1963. Preliminary geological report for Adelaide Island, Jefferson, T.H. 1980. Angiosperm fossils in supposed Jurassic 34 1 1961 - early 1963. British Antarctic Survey unpublished report. volcanogenic shales, Antarctica. Nature, 285, 187-188. 3 POURQUOI AD6/2/1963/G7. Meneilly, A.W. & Storey, B.C. 1981. Geology of parts of Adelaide 13 Dewar, G.J. 1965. The geology of Adelaide Island, British Antarctic Island, December 1981. British Antarctic Survey unpublished 67°40' S 67°40' S 12 PAS Territory. Ph.D. thesis, 189pp. report. AD6/2R/1981/G1. 3 Dewar, G.J. 1970. The geology of Adelaide Island. British Antarctic Moyes, A.B. 1979. The Mesozoic-Cenozoic plutonics of the 19 14 Survey Scientific Reports, No. 57, 66pp. Antarctic Peninsula. British Antarctic Survey unpublished report. Window Buttress Farquharson, G.W. 1980. Sedimentary sequences of Nordenskjöld AD6/2R/1979/G2. 11 ISLAND 6 MARGUERITE Coast and Adelaide Island. British Antarctic Survey unpublished Moyes, A.B., Willan, C.F.H. & Thomson, J.W. 1994. Geological map Gd-Ga report. AD6/2R/1980/G6. of Adelaide Island to Foyn Coast. BAS GEOMAP Series, Sheet 2 3 6Ga 3 Griffiths, C.J. 1991. Geological fieldwork on Adelaide Island 3, 1:250 000, with supplementary text. Cambridge, British 6Gd-Ga Antarctic Survey. 19 BAY 1990/91. British Antarctic Survey unpublished report . 3 6 26 Ga AD6/2R/1990/GL5. Pankhurst, R.J. 1982. Rb-Sr geochronology of Graham Land, Griffiths, C.J. 1992. Geological fieldwork on Adelaide Island Antarctica. Journal of the Geological Society, London, 139, 6 14 Jenny Island Gd-Ga 1991/92. British Antarctic Survey unpublished report. 701-711. Cape Alexandra AD6/2R/1991/GL. Riley, T.R. 2007. Geological Fieldwork on Adelaide Island, 2006/7. 21 Griffiths, C.J. & Oglethorpe, R.D. 1998. The stratigraphy and British Antarctic Survey unpublished report. AD6/2R/2006/GL2. Carvajal geochronology of Adelaide Island. Antarctic Science, 10, Riley, T.R, Flowerdew, M.J. & Whitehouse, M.J. in press. 462-475. Chronostratigraphy of a fore- to intra-arc basin, Adelaide Island, Avian Island 3 Haselwimmer, C.E., Riley, T.R. & Liu, J.G. 2010. Assessing the Antarctic Peninsula. Geological Magazine. potential of multispectral remote sensing for lithologic mapping Thomson, M.R.A. 1972. New discoveries of fossils in the Upper 69°00' W 68°40' 68°20' 68°00' 67°40' 67°20' W on the Antarctic Peninsula: case study from eastern Adelaide Jurassic Volcanic Group of Adelaide Island. British Antarctic Island, Graham Land. Antarctic Science, 22, 299-318. Survey Bulletin, 30, 95-101.

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