West Antarctica: Its tectonics and its relationship to East Antarctica
References
LeMasurier, W.E. 1972-b. Volcanic record of Cenozoic glacial history of Marie Byrd Land. In R.J. Adie (Ed.), Antarctic Geology and Geophysics.
LeMasurier, W.E. 1972-a. Volcanic record of Antarctic glacial history: Oslo: Universitetsforlaget. Implications with regard to Cenozoic sea levels. (Special publication U.S. Geological Survey. 1965. 1:500,000 Antarctica Sketch Map, Hobbs Coast Byrd Land. Reston Va.: U.S. Geological Survey. no. 4.) Institute of British Geographers.
West Antarctica: Its tectonics and its relationship to East Antarctica I. W. D. DALZIEL Lamont-Doherty Geological Observatory of Columbia University Palisades, New York 10964
R. J. PANKHURST British Antarctic Survey Cambridge CB3 OET, United Kingdom
A joint U.S. Antarctic Research Program (USARP)/British Antarctic Survey (BAs) geology and geophysics project was initiated
during the 1980-1981 antarctic season with the object of elucidating West Antarctica's tectonics and relationship to the East Antarctic craton (Doake, Crabtree, and Daiziel 1983). During the period from December 1983 to March 1984, the first full season of work was undertaken in the area between the base of the Antarctic Peninsula and the Thiel Mountains (see figure). Aviation fuel was flown in by USARP to the Martin Hills, Ellsworth Mountains, Mount Smart, and Siple Station, additional fuel was made available at South Pole Station. Two Twin Otter aircraft for close support of the geology party and for airborne geophysics were provided by BAS. Members of the geologic party were: from USARP, Ian W.D. Dalziel, Columbia University, New York; Anne M. Grunow, Columbia University, New York; and Walter R. Vennum, Sonoma State University, California; and from BAS Robert J. Pankhurst and Bryan F. Storey. The geophysical program was planned jointly and undertaken in the field by BAS scientists Stephen Garrett, Myron Maslanyj, and Howard Thompson. Detlef Damaske of the Bun-
Map showing localities mentioned in text. ("HH" denotes Hart Hills; "MJ" denotes Mount Johns; "MM" denotes Mount Moore; "MW" denotes Mount Woollard; "NH" denotes Nash Hills: "PH" denotes Pirrit Hills; "PN" denotes Pagano Nunatak; "SH" denotes Stewart Hills; "SN" denotes Sonntag Nunatak.)
1984 REVIEW
35
desanstalt für Geowissenschaften und Rohstoffe (BGR), Hannover, Federal Republic of Germany also participated in the geophysical field work. The Twin Otters were piloted by Captains Carry Studd (chief pilot). Ed Murton, and Richard Hasler. Geology. The geology program for 1983-1984 was concentrated on the Ellsworth Mountains/Thiel Mountains ridge (Craddock, Webers, and Anderson 1982). Work was undertaken in the Thiel and Whitmore Mountains; Hart, Nash, Martin, Pirrit, and Stewart Hills; Haag, Pagano, and Sonntag Nunataks; and Mounts Johns, Moore, and Woollard. In addition, brief visits were made to the northern Ellsworth Mountains and to the southwestern Patuxent Mountains (see figure). Basic field observations were undertaken by the whole party including detailed structural observations in the metasedimentary rocks by Bryan Storey and Ian Daiziel. Extensive collections were made for major and trace element geochemical analysis by Walter Vennum and for isotope geochemical studies by Robert Pankhurst. Anne Grunow and Ian Daiziel collected 608 cores and 38 oriented hand samples constituting 126 sites for paleomagnetic studies. Airborne geophysics. The geophysical program involved flying aeromagnetic and simultaneous radio-echo sounding surveys along two grids. One grid was located in a triangle between the Ellsworth, Thiel, and Whitmore Mountains; the other grid was between the Ellsworth Mountains and the base of the Antarctic Peninsula (see figure). Approximately 14,000 on-line kilometers of trace were flown. The joint USARP/BAS program will continue during the 1984-1985 season with geologic work in the Jones Mountains and Thurston Island/Eights Coast areas and airborne geophysics in the area between the Ellsworth Mountains, Thurston Island, and the base of the Antarctic Peninsula (see figure). Fuel has been made available by USARP at the Jones
Mountains, Mount Smart, and Siple Station. BAS Twin Otters will again be made available for close-support of the geological party and for airborne geophysics. Acknowledgments. The joint USARP/BAS program has benefited enormously from the enthusiastic support of Edward Todd (Director, Division of Polar Programs, National Science Foundation), Richard M. Laws (Director, BAS), Mort D. Turner (Program Manager, Polar Earth Sciences, Division of Polar Programs), and Charles W.M. Swithinbank (Head, Earth Science Division, BAS). Price Lewis, Kenneth Moulton, David Bresnahan, and Erik Chiang (Polar Operations Section, Division of Polar Programs) and John Hall (BAS Field Operations Manager, Rothera) provided invaluable support. The Antarctic Development Squadron (VXE-6) of the U.S. Navy Antarctic Support Force provided the essential LC-130 support. Finally, the willingness of Chuck Kroger (USARP) and of Ian Lovegrove and Paul Wood (BAs) to help all of us in many aspects of logistics and safety in the field is greatly appreciated. The U.S. part of the joint science program is supported by National Science Foundation grant DPP 82-13798 to Ian W.D. Dalziel. British Antarctic Survey is a component institute of the Natural Environment Research Council. References Craddock, C., G.E Webers, and J.J. Anderson. 1982. Geology of the Ellsworth Mountains-Thiel Mountains Ridge. In C. Craddock (Ed.), Antarctic geoscience. Madison: University of Wisconsin Press. Doake, C.S.M., R.D. Crabtree, and I.W.D. Dalziel. 1983. Subglacial morphology between Ellsworth Mountains and Antarctic Peninsula: New data and tectonic significance. In R.L. Oliver, P.R. James, and J.B. Jago (Eds.), Antarctic Earth sciences. Canberra: Australian Academy of Science.
Preliminary studies of a fossil flora from the Orville Coast-eastern Ellsworth Land, Antarctic Peninsula \
74' 72o
70o 680 56o
7Olander-Tolletson cHorner Nunataks
WEDDELL SEA
RONNE CE
Sky-Hi Nunataks
C. T. GEE
EASTERN Merrick Mts
Department of Botany University of Texas at Austin Austin, Texas 78713
(weeneT.
06 J gan baseca p ames
Mor
Nunataks
OWitte Nunataks ,
0
ELLSWORTH
Plant remains of a gymnospermous Jurassic flora were collected by a U.S. Geological Survey field team led by P.D. Rowley during the 1977-1978 field season from the Orville Coast and eastern Ellsworth Land regions of the southern Antarctic Peninsula. (See figure.) The area is underlain by Middle and Upper Jurassic volcaniclastic sedimentary rocks of the Latady Formation which interfinger with the caic-alkaline silicic volcanic rocks of the Mount Poster Formation (Rowley et al. in press). All of the rocks of the Latady Formation, which consists of dark36
Nunatak
76' LAN: Cape
o 20 40 60
F^-R ONNE ICE SHELF
KILOMETERS
Location map of the Orville Coast and eastern Ellsworth Land, Antarctic Peninsula. ANTARCTIC JOURNAL
LeMasurier, W.E. 1972-b. Volcanic record of Cenozoic glacial history of Marie Byrd Land. In R.J. Adie (Ed.), Antarctic Geology and Geophysics.
LeMasurier, W.E. 1972-a. Volcanic record of Antarctic glacial history: Oslo: Universitetsforlaget. Implications with regard to Cenozoic sea levels. (Special publication U.S. Geological Survey. 1965. 1:500,000 Antarctica Sketch Map, Hobbs Coast Byrd Land. Reston Va.: U.S. Geological Survey. no. 4.) Institute of British Geographers.
West Antarctica: Its tectonics and its relationship to East Antarctica I. W. D. DALZIEL Lamont-Doherty Geological Observatory of Columbia University Palisades, New York 10964
R. J. PANKHURST British Antarctic Survey Cambridge CB3 OET, United Kingdom
A joint U.S. Antarctic Research Program (USARP)/British Antarctic Survey (BAs) geology and geophysics project was initiated
during the 1980-1981 antarctic season with the object of elucidating West Antarctica's tectonics and relationship to the East Antarctic craton (Doake, Crabtree, and Daiziel 1983). During the period from December 1983 to March 1984, the first full season of work was undertaken in the area between the base of the Antarctic Peninsula and the Thiel Mountains (see figure). Aviation fuel was flown in by USARP to the Martin Hills, Ellsworth Mountains, Mount Smart, and Siple Station, additional fuel was made available at South Pole Station. Two Twin Otter aircraft for close support of the geology party and for airborne geophysics were provided by BAS. Members of the geologic party were: from USARP, Ian W.D. Dalziel, Columbia University, New York; Anne M. Grunow, Columbia University, New York; and Walter R. Vennum, Sonoma State University, California; and from BAS Robert J. Pankhurst and Bryan F. Storey. The geophysical program was planned jointly and undertaken in the field by BAS scientists Stephen Garrett, Myron Maslanyj, and Howard Thompson. Detlef Damaske of the Bun-
Map showing localities mentioned in text. ("HH" denotes Hart Hills; "MJ" denotes Mount Johns; "MM" denotes Mount Moore; "MW" denotes Mount Woollard; "NH" denotes Nash Hills: "PH" denotes Pirrit Hills; "PN" denotes Pagano Nunatak; "SH" denotes Stewart Hills; "SN" denotes Sonntag Nunatak.)
1984 REVIEW
35
desanstalt für Geowissenschaften und Rohstoffe (BGR), Hannover, Federal Republic of Germany also participated in the geophysical field work. The Twin Otters were piloted by Captains Carry Studd (chief pilot). Ed Murton, and Richard Hasler. Geology. The geology program for 1983-1984 was concentrated on the Ellsworth Mountains/Thiel Mountains ridge (Craddock, Webers, and Anderson 1982). Work was undertaken in the Thiel and Whitmore Mountains; Hart, Nash, Martin, Pirrit, and Stewart Hills; Haag, Pagano, and Sonntag Nunataks; and Mounts Johns, Moore, and Woollard. In addition, brief visits were made to the northern Ellsworth Mountains and to the southwestern Patuxent Mountains (see figure). Basic field observations were undertaken by the whole party including detailed structural observations in the metasedimentary rocks by Bryan Storey and Ian Daiziel. Extensive collections were made for major and trace element geochemical analysis by Walter Vennum and for isotope geochemical studies by Robert Pankhurst. Anne Grunow and Ian Daiziel collected 608 cores and 38 oriented hand samples constituting 126 sites for paleomagnetic studies. Airborne geophysics. The geophysical program involved flying aeromagnetic and simultaneous radio-echo sounding surveys along two grids. One grid was located in a triangle between the Ellsworth, Thiel, and Whitmore Mountains; the other grid was between the Ellsworth Mountains and the base of the Antarctic Peninsula (see figure). Approximately 14,000 on-line kilometers of trace were flown. The joint USARP/BAS program will continue during the 1984-1985 season with geologic work in the Jones Mountains and Thurston Island/Eights Coast areas and airborne geophysics in the area between the Ellsworth Mountains, Thurston Island, and the base of the Antarctic Peninsula (see figure). Fuel has been made available by USARP at the Jones
Mountains, Mount Smart, and Siple Station. BAS Twin Otters will again be made available for close-support of the geological party and for airborne geophysics. Acknowledgments. The joint USARP/BAS program has benefited enormously from the enthusiastic support of Edward Todd (Director, Division of Polar Programs, National Science Foundation), Richard M. Laws (Director, BAS), Mort D. Turner (Program Manager, Polar Earth Sciences, Division of Polar Programs), and Charles W.M. Swithinbank (Head, Earth Science Division, BAS). Price Lewis, Kenneth Moulton, David Bresnahan, and Erik Chiang (Polar Operations Section, Division of Polar Programs) and John Hall (BAS Field Operations Manager, Rothera) provided invaluable support. The Antarctic Development Squadron (VXE-6) of the U.S. Navy Antarctic Support Force provided the essential LC-130 support. Finally, the willingness of Chuck Kroger (USARP) and of Ian Lovegrove and Paul Wood (BAs) to help all of us in many aspects of logistics and safety in the field is greatly appreciated. The U.S. part of the joint science program is supported by National Science Foundation grant DPP 82-13798 to Ian W.D. Dalziel. British Antarctic Survey is a component institute of the Natural Environment Research Council. References Craddock, C., G.E Webers, and J.J. Anderson. 1982. Geology of the Ellsworth Mountains-Thiel Mountains Ridge. In C. Craddock (Ed.), Antarctic geoscience. Madison: University of Wisconsin Press. Doake, C.S.M., R.D. Crabtree, and I.W.D. Dalziel. 1983. Subglacial morphology between Ellsworth Mountains and Antarctic Peninsula: New data and tectonic significance. In R.L. Oliver, P.R. James, and J.B. Jago (Eds.), Antarctic Earth sciences. Canberra: Australian Academy of Science.
Preliminary studies of a fossil flora from the Orville Coast-eastern Ellsworth Land, Antarctic Peninsula \
74' 72o
70o 680 56o
7Olander-Tolletson cHorner Nunataks
WEDDELL SEA
RONNE CE
Sky-Hi Nunataks
C. T. GEE
EASTERN Merrick Mts
Department of Botany University of Texas at Austin Austin, Texas 78713
(weeneT.
06 J gan baseca p ames
Mor
Nunataks
OWitte Nunataks ,
0
ELLSWORTH
Plant remains of a gymnospermous Jurassic flora were collected by a U.S. Geological Survey field team led by P.D. Rowley during the 1977-1978 field season from the Orville Coast and eastern Ellsworth Land regions of the southern Antarctic Peninsula. (See figure.) The area is underlain by Middle and Upper Jurassic volcaniclastic sedimentary rocks of the Latady Formation which interfinger with the caic-alkaline silicic volcanic rocks of the Mount Poster Formation (Rowley et al. in press). All of the rocks of the Latady Formation, which consists of dark36
Nunatak
76' LAN: Cape
o 20 40 60
F^-R ONNE ICE SHELF
KILOMETERS
Location map of the Orville Coast and eastern Ellsworth Land, Antarctic Peninsula. ANTARCTIC JOURNAL
