Geology and petrography of DVDP hole 1, Hut Point Peninsula, Ross ...
Figure 3. A: stereographic net diagram of poles to foliation for Thala Hills (233 measurements). Contours are 0.5, 3, 6, 9, 12, and 15 percent area. 13( = 7r) axis plunges 100 to S. 71 0E. B: stereographic net diagram of lineations for Thala Hills (153 measurements). Contours are 1, 5, 15, 25, and 35 percent area. L, the lineation maximum, ()c plunges 14° to S. 71°E. C: stereographic net projection of poles to faults and mylonite zones. Triangles indicate left-handed movement sense (19 measurements). p—rough average of poles to faults and mylonite zones, one for each movement sense. o, 0 21 cr 31 inferred directions of principal stresses. The angle between the two averaged poles is 65°, that between O 3 and 8( = 7T) is 21°, and between O3 and L it is 23°. Dashed lines represent projections of planes perpendicular to the principal stresses. B
Halpern (University of Texas, Dallas). Calculated ages (y = 1.47 x 10 11 per year) on seven samples of quartzo-felds path ic gneiss range between about 700 and 2,275 million years, assuming an initial strontium-87/strontium-86 ratio of 0.705. Nine of eleven samples of the charnockitic gneiss gave an isochron with a slope of 987 ± 60 million years and an initial ratio of 0.719 ±0.0015 (95-percent confidence level). I am making a petrologic study with the electron microprobe of gneisses having the mineral assemblages quartz-plagioclase-K feldspar-biotite-orthopyroxene±garnet and quartz-plagioclase-K feldspa r-biotite-garnet ± sillimanite± cord ierite. W. I. Manton, University of Texas, Dallas, is making a uranium-thorium-lead isotope study of allanite and monazite from pegmatite. I thank P. K. Senko, chief of the 18th SAE, and other members of the expedition at Molodezhnaya for their logistics support, their cooperation, and their generous assistance for my field work. The research was supported by National Science Foun dation grant o pp 72-05797. References
Kamenev, Ye. N. 1972. Geological structure of Enderby Land. In: Antarctic Geology and Geophysics (Adie, R. J . , editor). Oslo, Universitetsforlaget. 579-583. Kamenev, Ye. N., L. V. Klimov, and 0. G. Shulyatin. 1965. Geologicheskoye stroyeniye Zemli Enderbi i Berega Printsa Ulafa (Geological structure of Enderby Land and of the Prince Olaf Coast). The Antarctic, The Committee Reports, 1964. Moscow, "Nauka" Publishing House. 5-27. Klimov, L. V. 1965a. Geologicheskoye issledovaniya v rayone Berega Printsa Ulafa v 1964 g. (Geological investigations in the region of the Prince Olaf Coast in 1964). Soviet Antarctic Expedition Information Bulletin, 51: 55-63. Klimov, L. V. 1965b. Geologicheskoye stroyeniye zapadnoy chasti Zemli Enderbi (Geologic structure of the western part of Enderby Land). Trudy of the Soviet Antarctic Expedition (7th cruise of d/e Ob 1961-1962), 44: 160-174. Myers, P. B., Jr., and E. E. MacNamara. 1970. Rocks of coastal
248
Enderby Land near Molodezhnaya Station, Antarctica. Antarctic Journal of the U.S., V(4): 158-159. Ravich, M. G., and Ye. N. Kamenev. 1972. Kristallicheskiy fundament A ntarkticheskoy platformy (Crystalline fundament of the Antarctic Platform). Leningrad, Gidrometeoizdat. 6581). Scharon, LeRoy, C. Scharnberger, Thomas Early, and Akira Shimoyana. 1970. International cooperation for paleomagnetic insight into antarctic tectonic history. Antarctic Journal of the U.S., V(5): 210-224. Trail, D. S., and I. R. Mcleod. 1969. Geology of Enderby Land. Antarctic Map Folio Series, 12 (sheet 11). New York, American Geographical Society.
Geology and petrography of DVDP hole 1, Hut Point Peninsula, Ross Island SAMUEL B. TREVES
and M. Z. ALL
Department of Geology University of Nebraska Lincoln, Nebraska 68508 Dry Valley Drilling Project (DvDP) hole 1 was drilled during the 1972-1973 austral summer on the south flank of Twin Crater, an extinct volcano near McMurdo Station, Ross Island (Treves and Kyle, 1973). Core recovered from the hole totaled 196.54 meters. The rocks penetrated consisted of 40 lava flows, nine pyroclastic units, and one dike. The flows are rather thin and most are oxidized. They exhibit phenocrystic kaersutite, augite, and ANTARCTIC JOURNAL
Modal analyses of flow units, DVDP hole 1, Hut Point Peninsula, Ross Island
ç t)
bC
.) . .2bJJ 1 H' H
2 3 4 5
6 7 7 9 10
11 12 13 14 15 16 17 18 18 19 20 21 22 23 24 1 24 25 27 28 28 29 29 29 30 31 33 34 35 37 40 41 43 45 46 47 48
3.03 2.27 1.17 0.49 0.87 1.11 4.58 4.58 2.31 1.75 1.77 1.41 2.36 3.18 3.10 2.97 3.83 7.24 7.24 1.72 4.43 1.91 4.54 2.52 3.78 3.78 0.88 3.40 6.30 6.30 5.44 5.44 5.44 0.85 2.29 1.34 6.87 0.71 7.05 3.86 0.50 0.36 0.55 3.22 3.81 2.31
1.00 4.82 5.58 6.78 7.67 8.17 12.21 13.18 15.08 17.10 18.43 20.04 22.09 23.91 27.26 32.33 32.95 39.04 41.01 44.14 48.14 50.95 53.51 57.94 59.03 62.00 63.00 81.53 81.62 87.18 88.55 91.43 91.45 93.93 94.51 104.80 111.37 112.27 121.88 131.36 131.84 133.76 134.41 137.11 138.12 142.51
A A B A A A A A A A A A A A A B B B B A A A A B A B C D A A E E E E E A
A
A C 1) C
28 30 30 24 26 40 37 38 38 37 35 35 30 32 30 38 58 50 47 42 42 43 33 35 36 56 34 43 66 64 60 53 53 25 25 24 22 21 22 61 53 60 56 52 50 57
C
22 25 22 26 21 25 24 24 25 17 17 18 18 17 20 19 24 26 26 11 20 19 19 18 26 12 13 20 16 15 18 19 25 29 30 33 29 34 30 18 10 19 22 19 22 18
Tr 2 8 () 4 2 2 2 2 5 5 5 6 2 2 3 4 3 3 4 3 3 5 8 10 2 4 0 2 2 0 0 0 0 0 0 8
0 4 2
2 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0
18 17 16 23 20 17 0 0
2 0
A= Kaersutite basalt B= Kacrsutjte andesite C=Trachytic kaersutite 1)= Pyroxene basalt andesite E= Pyroxene-olivine basalt
September/October 1975
a
40 28 24 29 15 6 11 11 12 15 17 18 22 22 20 17 0 0 21 11 10 19 25 6 11 37 0 0 0 0 0 0 18 18 7 6 a 13 0 20 0 0 0 0 0
olivine, and range from basalt to andesite. The pyroclastic units range from tuff to lapilli tuff to blocky breccia; two units show conglomeratic phases. The dike is andesitic. The table summarizes our petrographic results to date and indicates the modal mineralogy and nomenclature of the flow units and the dike (unit 28). Briefly, the basalts contain modal labradorite, andesites contain modal andesine, and trachytic andesites exhibit trachytic texture and contain modal oligoclase or andesine. Triangular plots of plagioclase-pyroxene-amphibole and plagioclase-pyroxene-olivine suggest that all of the flows are differentiates of common magma type. The earliest differentiate is a pyroxene-olivine basalt; the last is trachytic, kaersutite andesite. These petrographic and mineralogic data are compatible with field data (Treves, 1967) and chemical data (Goldich et al., in press). In the field, the units of hole 1 were assigned to five eruptive sequences and correlated with the rocks of DVDP hole 2 (Treves and Kyle, 1973). Subsequently, DVDP hole 3 was drilled (1973-1974 field season) (Kyle and Treves, 1974), and additional laboratory work was done on the rocks of holes 1, 2, and 3, and on the rocks of the surface exposures of Hut Point Peninsula (Kyle and Treves, 1974). These data indicate that the tentative correlation of Treves and Kyle (1973) needs revision. A revision based on the data presented here, on some chemical data, and on some recent radiometric dates was presented by Treves and Ali (1974). This research was supported by National Science Foundation grant ot,,p 74-20304. References
Goldich, S. S., S. B. Treves, N. H. Suhr, and J. S. Stticklcss. In press. Geochemistry of the Cenozoic volcanic rocks of Ross Island and vicinity Antarctica. Journal of Geology. Kyle, P. R., and S. B. Treves. 1974. Geology of DVDP 3, Hut Point Peninsula, Ross Island, Antarctica. In: Thy Valley Drilling Project Bulletin 3. DeKaib, Northern Illinois University. 1348. Kyle, P. R., and S. B. Trcves. 1974. Geology of Hut Point Peninsula, Ross Island. Antarctic Journal of the U.S., IX(5): 232234. Treves, S. B. 1967. Volcanic rocks from the Marguerite Bay, Ross Island, and Mt. Weaver areas, Antarctica. Tokyo, Department of Polar Research, Japanese Antarctic Research Expedition. Scientific Reports, 1. Treves, S. B., and M. Z. Ali. 1974. Geology and petrography of DVDP 1, Hut Point Peninsula, Ross Island, Antarctica. In: Thy Valley Drilling Project Bulletin 4. DeKalb, Northern Illinois University. 60-61 (abstract). Treves, S. B., and P. R. Kyle. 1973. Geology of DVDP I and 2, Hut Point Peninsula, Ross Island, Antarctica. In: Dry Valley Drilling Project Bulletin 2. DeKalb, Northern Illinois University. 11-82.
249
Halpern (University of Texas, Dallas). Calculated ages (y = 1.47 x 10 11 per year) on seven samples of quartzo-felds path ic gneiss range between about 700 and 2,275 million years, assuming an initial strontium-87/strontium-86 ratio of 0.705. Nine of eleven samples of the charnockitic gneiss gave an isochron with a slope of 987 ± 60 million years and an initial ratio of 0.719 ±0.0015 (95-percent confidence level). I am making a petrologic study with the electron microprobe of gneisses having the mineral assemblages quartz-plagioclase-K feldspar-biotite-orthopyroxene±garnet and quartz-plagioclase-K feldspa r-biotite-garnet ± sillimanite± cord ierite. W. I. Manton, University of Texas, Dallas, is making a uranium-thorium-lead isotope study of allanite and monazite from pegmatite. I thank P. K. Senko, chief of the 18th SAE, and other members of the expedition at Molodezhnaya for their logistics support, their cooperation, and their generous assistance for my field work. The research was supported by National Science Foun dation grant o pp 72-05797. References
Kamenev, Ye. N. 1972. Geological structure of Enderby Land. In: Antarctic Geology and Geophysics (Adie, R. J . , editor). Oslo, Universitetsforlaget. 579-583. Kamenev, Ye. N., L. V. Klimov, and 0. G. Shulyatin. 1965. Geologicheskoye stroyeniye Zemli Enderbi i Berega Printsa Ulafa (Geological structure of Enderby Land and of the Prince Olaf Coast). The Antarctic, The Committee Reports, 1964. Moscow, "Nauka" Publishing House. 5-27. Klimov, L. V. 1965a. Geologicheskoye issledovaniya v rayone Berega Printsa Ulafa v 1964 g. (Geological investigations in the region of the Prince Olaf Coast in 1964). Soviet Antarctic Expedition Information Bulletin, 51: 55-63. Klimov, L. V. 1965b. Geologicheskoye stroyeniye zapadnoy chasti Zemli Enderbi (Geologic structure of the western part of Enderby Land). Trudy of the Soviet Antarctic Expedition (7th cruise of d/e Ob 1961-1962), 44: 160-174. Myers, P. B., Jr., and E. E. MacNamara. 1970. Rocks of coastal
248
Enderby Land near Molodezhnaya Station, Antarctica. Antarctic Journal of the U.S., V(4): 158-159. Ravich, M. G., and Ye. N. Kamenev. 1972. Kristallicheskiy fundament A ntarkticheskoy platformy (Crystalline fundament of the Antarctic Platform). Leningrad, Gidrometeoizdat. 6581). Scharon, LeRoy, C. Scharnberger, Thomas Early, and Akira Shimoyana. 1970. International cooperation for paleomagnetic insight into antarctic tectonic history. Antarctic Journal of the U.S., V(5): 210-224. Trail, D. S., and I. R. Mcleod. 1969. Geology of Enderby Land. Antarctic Map Folio Series, 12 (sheet 11). New York, American Geographical Society.
Geology and petrography of DVDP hole 1, Hut Point Peninsula, Ross Island SAMUEL B. TREVES
and M. Z. ALL
Department of Geology University of Nebraska Lincoln, Nebraska 68508 Dry Valley Drilling Project (DvDP) hole 1 was drilled during the 1972-1973 austral summer on the south flank of Twin Crater, an extinct volcano near McMurdo Station, Ross Island (Treves and Kyle, 1973). Core recovered from the hole totaled 196.54 meters. The rocks penetrated consisted of 40 lava flows, nine pyroclastic units, and one dike. The flows are rather thin and most are oxidized. They exhibit phenocrystic kaersutite, augite, and ANTARCTIC JOURNAL
Modal analyses of flow units, DVDP hole 1, Hut Point Peninsula, Ross Island
ç t)
bC
.) . .2bJJ 1 H' H
2 3 4 5
6 7 7 9 10
11 12 13 14 15 16 17 18 18 19 20 21 22 23 24 1 24 25 27 28 28 29 29 29 30 31 33 34 35 37 40 41 43 45 46 47 48
3.03 2.27 1.17 0.49 0.87 1.11 4.58 4.58 2.31 1.75 1.77 1.41 2.36 3.18 3.10 2.97 3.83 7.24 7.24 1.72 4.43 1.91 4.54 2.52 3.78 3.78 0.88 3.40 6.30 6.30 5.44 5.44 5.44 0.85 2.29 1.34 6.87 0.71 7.05 3.86 0.50 0.36 0.55 3.22 3.81 2.31
1.00 4.82 5.58 6.78 7.67 8.17 12.21 13.18 15.08 17.10 18.43 20.04 22.09 23.91 27.26 32.33 32.95 39.04 41.01 44.14 48.14 50.95 53.51 57.94 59.03 62.00 63.00 81.53 81.62 87.18 88.55 91.43 91.45 93.93 94.51 104.80 111.37 112.27 121.88 131.36 131.84 133.76 134.41 137.11 138.12 142.51
A A B A A A A A A A A A A A A B B B B A A A A B A B C D A A E E E E E A
A
A C 1) C
28 30 30 24 26 40 37 38 38 37 35 35 30 32 30 38 58 50 47 42 42 43 33 35 36 56 34 43 66 64 60 53 53 25 25 24 22 21 22 61 53 60 56 52 50 57
C
22 25 22 26 21 25 24 24 25 17 17 18 18 17 20 19 24 26 26 11 20 19 19 18 26 12 13 20 16 15 18 19 25 29 30 33 29 34 30 18 10 19 22 19 22 18
Tr 2 8 () 4 2 2 2 2 5 5 5 6 2 2 3 4 3 3 4 3 3 5 8 10 2 4 0 2 2 0 0 0 0 0 0 8
0 4 2
2 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0
18 17 16 23 20 17 0 0
2 0
A= Kaersutite basalt B= Kacrsutjte andesite C=Trachytic kaersutite 1)= Pyroxene basalt andesite E= Pyroxene-olivine basalt
September/October 1975
a
40 28 24 29 15 6 11 11 12 15 17 18 22 22 20 17 0 0 21 11 10 19 25 6 11 37 0 0 0 0 0 0 18 18 7 6 a 13 0 20 0 0 0 0 0
olivine, and range from basalt to andesite. The pyroclastic units range from tuff to lapilli tuff to blocky breccia; two units show conglomeratic phases. The dike is andesitic. The table summarizes our petrographic results to date and indicates the modal mineralogy and nomenclature of the flow units and the dike (unit 28). Briefly, the basalts contain modal labradorite, andesites contain modal andesine, and trachytic andesites exhibit trachytic texture and contain modal oligoclase or andesine. Triangular plots of plagioclase-pyroxene-amphibole and plagioclase-pyroxene-olivine suggest that all of the flows are differentiates of common magma type. The earliest differentiate is a pyroxene-olivine basalt; the last is trachytic, kaersutite andesite. These petrographic and mineralogic data are compatible with field data (Treves, 1967) and chemical data (Goldich et al., in press). In the field, the units of hole 1 were assigned to five eruptive sequences and correlated with the rocks of DVDP hole 2 (Treves and Kyle, 1973). Subsequently, DVDP hole 3 was drilled (1973-1974 field season) (Kyle and Treves, 1974), and additional laboratory work was done on the rocks of holes 1, 2, and 3, and on the rocks of the surface exposures of Hut Point Peninsula (Kyle and Treves, 1974). These data indicate that the tentative correlation of Treves and Kyle (1973) needs revision. A revision based on the data presented here, on some chemical data, and on some recent radiometric dates was presented by Treves and Ali (1974). This research was supported by National Science Foundation grant ot,,p 74-20304. References
Goldich, S. S., S. B. Treves, N. H. Suhr, and J. S. Stticklcss. In press. Geochemistry of the Cenozoic volcanic rocks of Ross Island and vicinity Antarctica. Journal of Geology. Kyle, P. R., and S. B. Treves. 1974. Geology of DVDP 3, Hut Point Peninsula, Ross Island, Antarctica. In: Thy Valley Drilling Project Bulletin 3. DeKaib, Northern Illinois University. 1348. Kyle, P. R., and S. B. Trcves. 1974. Geology of Hut Point Peninsula, Ross Island. Antarctic Journal of the U.S., IX(5): 232234. Treves, S. B. 1967. Volcanic rocks from the Marguerite Bay, Ross Island, and Mt. Weaver areas, Antarctica. Tokyo, Department of Polar Research, Japanese Antarctic Research Expedition. Scientific Reports, 1. Treves, S. B., and M. Z. Ali. 1974. Geology and petrography of DVDP 1, Hut Point Peninsula, Ross Island, Antarctica. In: Thy Valley Drilling Project Bulletin 4. DeKalb, Northern Illinois University. 60-61 (abstract). Treves, S. B., and P. R. Kyle. 1973. Geology of DVDP I and 2, Hut Point Peninsula, Ross Island, Antarctica. In: Dry Valley Drilling Project Bulletin 2. DeKalb, Northern Illinois University. 11-82.
249
