Hyaloclastite of DVDP 3, Hut Point Peninsula, Antarctica
ages are possible, but no other fossils were found to date the sequence more precisely. Paleocurrent directions measured in approximately 30 localities indicate that all turbidites were deposited from south to north. Flute casts (figure 2), crossbeds, tool marks, and ripple-mark orientations were used for paleocurrent determinations and were corrected for present dip of the beds. Preliminary thin section petrography of the coarser rocks collected indicates sedimentary and metamorphic source areas for the Robertson Bay Group, but unlike previous studies, a minor mafic volcanic rock fragment component was observed consistently (figure 3). The Robertson Bay Group rocks have been metamorphosed to corderite/biotite/hornblende hornfels by Devonian intrusives. The mechanism of emplacement seems to be by stoping. We saw no evidence for major forcible injection. This, plus the absence of sediments derived from uplifts normally associated with orogeny, limits this event to granitic intrusives. Thus, the "Borchgrevink" Orogeny, a proposed mountain-building event, does not seem to be a true orogeny, at least in north Victoria Land. These preliminary findings will be augmented by further research on the samples. Relationships to rocks in the
S
AMP
.
0
::-
e
-
-a..
r*
a
Figure 2. Flute casts on bottom of a turbidite bed. Hammer is
used for scale. Robertson Bay, northern Victoria Land.
Hyaloclastite of DVDP 3, Hut Point Peninsula, Antarctica SAMUEL B. TREVES
Department of Geology University of Nebraska Lincoln, Nebraska 68588
Figure 3. Photomicrograph of coarse-grained Robertson Bay Group turbidite. Note sedimentary (a) and igneous (b) rock fragments. Fragments are approximately 2 millimeters in diameter. USARP Mountains (Wilson Group in the Daniels Range) and the Bowers Graben (Bowers Supergroup between the Leap Year and Rennick Glaciers) were also investigated by GANOVEX. The new data may shed more light on Precambrian events that helped form this rock group. This work was supported in part by National Science Foundation grant EAR 78-23645 and in part by the BGR of West Germany. References Crowder, D. F. 1968. Geology of a part of northern Victoria Land, Antarctica. U.S. Geological Survey Professional Paper, 600-D, 95-107. Harrington, H. J . , Wood, B. L., McKellar, I. C., and Lensen, G. J. 1967. Topography and geology of the Cape Hallette District, Victoria Land, Antarctica. New Zealand Geological Survey Bulletin, 80, 100 pp. LeCouteur, P. C., and Leitch, E. C. 1964. Preliminary report on the geology of an area south-east of the Upper Tucker Glacier, northern Victoria Land. In R. J . Adie (Ed.), Antarctic Geology. Amsterdam: North-Holland Publishing Co. Mutti, E., and Ricci Lucchi, F. 1972. Turbidites of the northern Apennines: Introduction to facies analysis. International Geology Review, 20, 125-166. Rastall, R. H., and Priestley. R. E. 1921. The slate-graywacke formation of Robertson Bay: British Antarctica ('Terra Nova') expedition, 1910, natural history report. Geology, 1, 121-129. Sturm, A. G., and Carryer, S. 1970. Geology of the region between Matusevich and Tucker Glaciers, northern Victoria Land. Antarctica. New Zealand Journal of Geology and Geophysics, 13, 408-435.
Dry Valley Drilling Project (DVDP) was drilled 3 meters north of DVDP 2 (77 0 50' 59.59"S 166 0 40' 26.68"E) at the base of Observation Hill during WINFLY of the 1973-74 field season (Kyle and Treves 1974). Drilling produced about 380 meters of core. The rocks penetrated consist of 10 flows and 5 fragmental units. The oldest unit is a hyaloclastite and is 214 meters thick. It is the subject of this report. From top to bottom the hyaloclastite consists of 21 meters of mixed volcanic breccia that is primarily a blocky ANTARCTIC JOURNAL
palagonitic lapilli tuff. Some basaltic units as much as 6 meters thick occur in this interval. It is difficult to determine whether these units are flows, pillows, or large blocks. Most of these units exhibit shattered bases and some have chilled margins. The remainder of the hyaloclastite consists primarily of lapilli tuff and blocky lapilli tuff with minor mixed tuff and black vitric tuff. Petrographic examination of 120 thin sections of this unit indicate that almost all of the lapilli and blocks are glassy olivine basalt. Experience and some preliminary chemical work indicate that the rocks are basanites or nepheline basanites. Detailed examination of the core revealed a petrographic anomaly at a depth of 218 meters. At this point a tuff contains lapilli, such as trachyte and nepheline hawaiite that do not occur in the hyaloclastite below this depth. This suggests that the lapilli do not come from the immediate area. Rocks of this type do occur to the north, south, east, and southwest of DVDP 3. Kyle and Price (1975) also note that rhOnite occurs in the basaltic clasts of the hyaloclastite above this horizon and, further, that it does not occur in clasts below this horizon. Morelli (1973) found diatoms in core from the upper reaches of the hyaloclastite. Brady (1976) studied the Morelli slides and reported that the diatoms were freshwater types. Additional information about the origin and environ ment of depositions of the hyaloclastite may be gleaned from the data of Nakai, Mizutani, and Tanizawa (1978) and Lyon (1974), which may be interpreted to indicate that the lower reaches of the core, below 218 meters, erupted into seawater and that the upper part erupted into fresh or brackish water and subaerially. The data presented above allow a reconstruction of the geologic history. It seems reasonable in light of all of this data and the geologic history of Hut Point Peninsula (Kyle and Treves 1973) to suggest that the rocks of DVDP 3 record a period of submarine volcanism in McMurdo Sound that produced a volcanic pedestal upon which the flows now exposed at the surface accumulated. The data also indicate
Paleomagnetic investigation of Cenozoic glaciogenic sediments, Taylor Valley and McMurdo Sound DONALD P. ELSTON
and
STEPHEN L. BRESSLER
U.S. Geological Survey Flagstaff, Arizona 86001 This work is part of an international multidisciplinary investigation of the Cenozoic glacial history of the Dry Valleys and McMurdo Sound region. During November 1979, we collected for paleomagnetic analysis 48 oriented samples from surficial deposits in Taylor Dry Valley and 173 samples from core of New Zealand's McMurdo Sound 1980 REVIEW
that a break in the volcanism occurred. During this break lapilli from another volcanic center were transported to this site, perhaps by ice. The remainder of the hyaloclastite, that above 218 meters, accumulated in a fresh or brackish water environment, perhaps under and in contact with an ice shelf or an ice sheet. Radiometric dates (Kyle, Sutter, and Treves 1978) of a basaltic clast from the upper part of the hyaloclastite, of other specimens of the core of DVDP 1 and 2, and of surface samples (Armstrong 1978) indicate that these volcanic rocks accumulated quickly about a million years ago. This research was supported by National Science Foundation grant DPP 72-05800. The hyaloclastite of DVDP 3 was moved from Northern Illinois University to the University of Nebraska-Lincoln. It is our intention to relog the core carefully and to investigate it in detail. References Armstrong, R. L. 1978. K/Ar dating: Late Cenozoic McMurdo Volcanic Group and dry valley glacial history, Victoria Land, Antarctica. New Zealand Journal of Geology and Geophysics, 21(6), 685-698. Brady, H. 1976. Personal communication. Kyle, P. R., and Price, R. C. 1975. Occurrences of rhOnite in alkalic lavas of the McMurdo volcanic group, Antarctica and Dunedin volcano, New Zealand. American Mineralogist, 60, 722-725. Kyle, P. R., Sutter, J. F., and Treves, S. B. 1978. K/Ar age determinations on DVDP 1 and 2 core samples. Dry Valley Drilling Project, 8, 46-47. Kyle, P. R., and Treves, S. B. 1973. Review of the geology of Hut Point Peninsula, Ross Island, Antarctica. Dry Valley Drilling Project, 2, 1-10. Kyle, P. R., and Treves, S. B. 1974. Geology of DVDP 3, Hut Point Peninsula, Ross Island, Antarctica. Dry Valley Drilling Project, 3, 13-48. Lyon, G. L. 1974. Stable isotope analyses of ice from DVDP 3. Dry Valley Drilling Project, 3, 160-170. Morelli, F. A. 1973. Personal communication. Nakai, N., Mizutani, Y., and Tanizawa, K. 1978. Stable isotope studies: Past volcanic events deduced from H, 0, S and C isotopic composition of ice and salts from DVDP 3. Dry Valley Drilling Project, 8, 66-67.
Sediment and Tectonic Study (MssTs) drill hole 1. Objectives of this work are (1) to provide an improved assessment of the ages of the glaciogenic sediments by correlation of magnetic polarity and polarity zonations with the polarity time scale, and (2) to see if correlations exist with polarity zonations already developed from core of Dry Valley Drilling Project (DVDP) holes 8, 10, 11, and 12 drilled in Taylor Valley. Field work in Taylor Valley was conducted 15-22 Novem ber 1979. Outcrops of stratified glacial deposits were sampled adjacent to the terminus of Lacroix Glacier in central Taylor Valley (site 1, figure) and adjacent to Commonwealth Stream between New Harbor and Commonwealth Glacier (site 2). These sites mark the best exposures of stratified deposits in Taylor Valley. Hendy, Healy, Rayner, and Wil son (1979) have reported Uranium-thorium (U-Th) ages of 350,000 to 74,000 years from carbonate in the Lacroix Glacier section. All 29 oriented samples from approximately 9
S
AMP
.
0
::-
e
-
-a..
r*
a
Figure 2. Flute casts on bottom of a turbidite bed. Hammer is
used for scale. Robertson Bay, northern Victoria Land.
Hyaloclastite of DVDP 3, Hut Point Peninsula, Antarctica SAMUEL B. TREVES
Department of Geology University of Nebraska Lincoln, Nebraska 68588
Figure 3. Photomicrograph of coarse-grained Robertson Bay Group turbidite. Note sedimentary (a) and igneous (b) rock fragments. Fragments are approximately 2 millimeters in diameter. USARP Mountains (Wilson Group in the Daniels Range) and the Bowers Graben (Bowers Supergroup between the Leap Year and Rennick Glaciers) were also investigated by GANOVEX. The new data may shed more light on Precambrian events that helped form this rock group. This work was supported in part by National Science Foundation grant EAR 78-23645 and in part by the BGR of West Germany. References Crowder, D. F. 1968. Geology of a part of northern Victoria Land, Antarctica. U.S. Geological Survey Professional Paper, 600-D, 95-107. Harrington, H. J . , Wood, B. L., McKellar, I. C., and Lensen, G. J. 1967. Topography and geology of the Cape Hallette District, Victoria Land, Antarctica. New Zealand Geological Survey Bulletin, 80, 100 pp. LeCouteur, P. C., and Leitch, E. C. 1964. Preliminary report on the geology of an area south-east of the Upper Tucker Glacier, northern Victoria Land. In R. J . Adie (Ed.), Antarctic Geology. Amsterdam: North-Holland Publishing Co. Mutti, E., and Ricci Lucchi, F. 1972. Turbidites of the northern Apennines: Introduction to facies analysis. International Geology Review, 20, 125-166. Rastall, R. H., and Priestley. R. E. 1921. The slate-graywacke formation of Robertson Bay: British Antarctica ('Terra Nova') expedition, 1910, natural history report. Geology, 1, 121-129. Sturm, A. G., and Carryer, S. 1970. Geology of the region between Matusevich and Tucker Glaciers, northern Victoria Land. Antarctica. New Zealand Journal of Geology and Geophysics, 13, 408-435.
Dry Valley Drilling Project (DVDP) was drilled 3 meters north of DVDP 2 (77 0 50' 59.59"S 166 0 40' 26.68"E) at the base of Observation Hill during WINFLY of the 1973-74 field season (Kyle and Treves 1974). Drilling produced about 380 meters of core. The rocks penetrated consist of 10 flows and 5 fragmental units. The oldest unit is a hyaloclastite and is 214 meters thick. It is the subject of this report. From top to bottom the hyaloclastite consists of 21 meters of mixed volcanic breccia that is primarily a blocky ANTARCTIC JOURNAL
palagonitic lapilli tuff. Some basaltic units as much as 6 meters thick occur in this interval. It is difficult to determine whether these units are flows, pillows, or large blocks. Most of these units exhibit shattered bases and some have chilled margins. The remainder of the hyaloclastite consists primarily of lapilli tuff and blocky lapilli tuff with minor mixed tuff and black vitric tuff. Petrographic examination of 120 thin sections of this unit indicate that almost all of the lapilli and blocks are glassy olivine basalt. Experience and some preliminary chemical work indicate that the rocks are basanites or nepheline basanites. Detailed examination of the core revealed a petrographic anomaly at a depth of 218 meters. At this point a tuff contains lapilli, such as trachyte and nepheline hawaiite that do not occur in the hyaloclastite below this depth. This suggests that the lapilli do not come from the immediate area. Rocks of this type do occur to the north, south, east, and southwest of DVDP 3. Kyle and Price (1975) also note that rhOnite occurs in the basaltic clasts of the hyaloclastite above this horizon and, further, that it does not occur in clasts below this horizon. Morelli (1973) found diatoms in core from the upper reaches of the hyaloclastite. Brady (1976) studied the Morelli slides and reported that the diatoms were freshwater types. Additional information about the origin and environ ment of depositions of the hyaloclastite may be gleaned from the data of Nakai, Mizutani, and Tanizawa (1978) and Lyon (1974), which may be interpreted to indicate that the lower reaches of the core, below 218 meters, erupted into seawater and that the upper part erupted into fresh or brackish water and subaerially. The data presented above allow a reconstruction of the geologic history. It seems reasonable in light of all of this data and the geologic history of Hut Point Peninsula (Kyle and Treves 1973) to suggest that the rocks of DVDP 3 record a period of submarine volcanism in McMurdo Sound that produced a volcanic pedestal upon which the flows now exposed at the surface accumulated. The data also indicate
Paleomagnetic investigation of Cenozoic glaciogenic sediments, Taylor Valley and McMurdo Sound DONALD P. ELSTON
and
STEPHEN L. BRESSLER
U.S. Geological Survey Flagstaff, Arizona 86001 This work is part of an international multidisciplinary investigation of the Cenozoic glacial history of the Dry Valleys and McMurdo Sound region. During November 1979, we collected for paleomagnetic analysis 48 oriented samples from surficial deposits in Taylor Dry Valley and 173 samples from core of New Zealand's McMurdo Sound 1980 REVIEW
that a break in the volcanism occurred. During this break lapilli from another volcanic center were transported to this site, perhaps by ice. The remainder of the hyaloclastite, that above 218 meters, accumulated in a fresh or brackish water environment, perhaps under and in contact with an ice shelf or an ice sheet. Radiometric dates (Kyle, Sutter, and Treves 1978) of a basaltic clast from the upper part of the hyaloclastite, of other specimens of the core of DVDP 1 and 2, and of surface samples (Armstrong 1978) indicate that these volcanic rocks accumulated quickly about a million years ago. This research was supported by National Science Foundation grant DPP 72-05800. The hyaloclastite of DVDP 3 was moved from Northern Illinois University to the University of Nebraska-Lincoln. It is our intention to relog the core carefully and to investigate it in detail. References Armstrong, R. L. 1978. K/Ar dating: Late Cenozoic McMurdo Volcanic Group and dry valley glacial history, Victoria Land, Antarctica. New Zealand Journal of Geology and Geophysics, 21(6), 685-698. Brady, H. 1976. Personal communication. Kyle, P. R., and Price, R. C. 1975. Occurrences of rhOnite in alkalic lavas of the McMurdo volcanic group, Antarctica and Dunedin volcano, New Zealand. American Mineralogist, 60, 722-725. Kyle, P. R., Sutter, J. F., and Treves, S. B. 1978. K/Ar age determinations on DVDP 1 and 2 core samples. Dry Valley Drilling Project, 8, 46-47. Kyle, P. R., and Treves, S. B. 1973. Review of the geology of Hut Point Peninsula, Ross Island, Antarctica. Dry Valley Drilling Project, 2, 1-10. Kyle, P. R., and Treves, S. B. 1974. Geology of DVDP 3, Hut Point Peninsula, Ross Island, Antarctica. Dry Valley Drilling Project, 3, 13-48. Lyon, G. L. 1974. Stable isotope analyses of ice from DVDP 3. Dry Valley Drilling Project, 3, 160-170. Morelli, F. A. 1973. Personal communication. Nakai, N., Mizutani, Y., and Tanizawa, K. 1978. Stable isotope studies: Past volcanic events deduced from H, 0, S and C isotopic composition of ice and salts from DVDP 3. Dry Valley Drilling Project, 8, 66-67.
Sediment and Tectonic Study (MssTs) drill hole 1. Objectives of this work are (1) to provide an improved assessment of the ages of the glaciogenic sediments by correlation of magnetic polarity and polarity zonations with the polarity time scale, and (2) to see if correlations exist with polarity zonations already developed from core of Dry Valley Drilling Project (DVDP) holes 8, 10, 11, and 12 drilled in Taylor Valley. Field work in Taylor Valley was conducted 15-22 Novem ber 1979. Outcrops of stratified glacial deposits were sampled adjacent to the terminus of Lacroix Glacier in central Taylor Valley (site 1, figure) and adjacent to Commonwealth Stream between New Harbor and Commonwealth Glacier (site 2). These sites mark the best exposures of stratified deposits in Taylor Valley. Hendy, Healy, Rayner, and Wil son (1979) have reported Uranium-thorium (U-Th) ages of 350,000 to 74,000 years from carbonate in the Lacroix Glacier section. All 29 oriented samples from approximately 9
