Soil weathering sequences in Wright Valley
References
Armstrong, R L. In press. K-Ar dating: McMurdo volcanics and Dry Valley glacial history, Victoria Land, Antarctica (New Zealand Journal of Geology and Geophysics). Goldich, S. S., S. B. Treves, N. H. Suhr, and J. S. Stuckless. 1975. Geochemistry of the Cenozoic volcanic rocks of Ross Island and vicinity, Antarctica. Journal of Geology, 83: 415-435. Gunn, B. M., and G. Warren. 1962. Geology of Victoria Land between the Mawson and Mulock Glaciers, Antarctica. Bulletin New Zealand Geological Survey, 71: 157. Kyle, P. R., andJ. W. Cole. 1974. Structural control of volcanism in the McMurdo volcanic group, Antarctica. Bulletin Volcanologique, 38(1): 16-25. Kyle, P. R, and P. C. Rankin. 1976. Rare-earth element geochemistry of the McMurdo volcanic group, Antarctica. Geochimica et CosmochimicaActa, 40: 1497-1507. Skinner, D. N. B. In press. Stratigraphy and structure of lower grade metasediments of Skelton Group, McMurdo Sound—Does Teall Greywacke really exist? Proceedings of the Third Symposium on Antarctic Geology and Geophysics, Madison, Wisconsin, 1977.
Soil weathering sequences in Wright Valley J . G. BOCKHEIM
Department of Soil Science University of Wisconsin Madison, Wisconsin 53706
During the 1977-78 field season, I examined soils in Wright Valley to establish their relationship to Wright Lower, Wright Upper, and alpine glaciations and to compare them with soils previously investigated in Taylor Valley (Bockheim, 1977). Detailed descriptions were made for 55 profiles. I collected 295 soil samples and recorded surface weathering features at 28 localities. Laboratory and field methods were described earlier (Bockheim, 1977). Wright Lower Glaciations. Soil properties and surface weathering were examined on moraines of the Trilogy (see figure, location A) and Loop (figure, location B) glacial episodes (Nichols, 1971). Several small, indistinct lateral moraines extending about 100 meters above the Loop Moraine (figure, Cl) and an associated end moraine (figure, C2) 1.6 kilometers west of the Loop Moraine also were examined. Finally, several small, indistinct lateral moraine segments on the north side of the valley 1.5 kilometers west of the C2 end moraine were sampled (figure, D). Soils on the various moraines differ markedly in depths of oxidation, ghosts, salt encrustations, and coherence (table 1). Soils on D moraines feature a salt-cemented horizon averaging 12 centimeters in thickness. In places these soils overlie buried soils derived from a light gray, silty, pulverulent drift 36
which crops out widely further up-valley to the west. Trilogy, Loop, C, and D moraines were distringuished on the basis of surface boulder frequency, fragmentation of boulder in situ, and the extent of cavernous weathering and ventifaction (table 2). Alpine Glaciations. Alpine moraines were examined adjacent to the Goodspeed, Hart, Meserve, and Bartley Glaciers. A sequence similar to that described by Behling (1971) and Everett (1971) was observed. Soil morphology and surface weathering data appear in tables 1 and 2. Alpine I and II soils are similar to Alpine I (II in Denton et al., 1971) and 11(111) soils in Taylor Valley (Bockheim, 1977). However, soils equivalent to Alpine III soils in Wright Valley were not observed in Taylor Valley. This suggests that Alpine III moraines, if they existed in Taylor Valley, were destroyed by the subsequent Taylor IV glaciation(s) or by Ross Sea glaciations. Wright Valley, to the east of Lake Vanda, apparently has not experienced major axial glaciations from the Polar Plateau in the past 4.2 million years (Fleck et al., 1972). A less plausible explanation for the lack of Alpine III moraines in Taylor Valley is that the mechanisms controlling the fluctuations of alpine glaciers in Taylor and Wright Valleys may differ and Alpine III moraines may never have existed in Taylor Valley. The lower portions of Alpine III moraines adjacent to Hart and Meserve Glaciers, and possibly to the Bartley Glacier, have been overridden by advances of the Wright Lower Glacier (table 3). Surface weathering is less on the lower, overridden portions of these lateral moraines. Salt pans, which are common to Alpine III soils above the junction, are conspicuously absent in the portion of the moraine that has been reworked by ice from the Wright Lower Glacier. Wright Upper Glacier. Silt deposits depicted by Vucetich and Topping (1972) as representing the Prospect Formation were examined in detail at three locations: 726, 730, and 734 (figure). Soils derived from the silts have a characteristic light gray (2.5Y 7/2, Munsell soil color chart notation) color, are poorly oxidized, and are pulverulent or powdery. The soils feature a thin (7 centimeter), white, salt-indurated layer just below the surface. Striated diabase cobbles were found within soils 726 and 734. Soils derived from the fine-textured Prospect Formation are poorly developed. However, at Prospect Mesa (figure, E) soils developed in coarser textured debris fan material overlying the Prospect sediments are among the most strongly developed soils that have been examined in Wright Valley (tables 1 and 2). The soils are oxidized to about 25 centimeters, contain ghosts to depths exceeding 25 centimeters, and feature a salt pan at least 15 centimeters thick. Correlation of Wright Valley and Taylor Valley Soils. Using soil properties and surface weathering criteria, moraines of Wright Valley and Taylor Valley are correlated in table 4. The correlations are subject to revision following further field work in Wright Valley and examination of laboratory data. All soil pits were backfilled and the landscape restored to its original conditions as near as possible. This research was supported by National Science Foundation grant DPP 74-20991 to George H. Denton, University of Maine. I am grateful to him for his assistance in locating critical sites for soils investigation, for valuable discussions in the field, and for reviewing this manuscript. A. James Pastene, Ernest F. S. Downes, and Montague Alford assisted in the field work. ANTARCTIC JOURNAL
OLYMPUS RANGE
Tm GLACIER
DAIS
Jr ASGARD RANGE
Map of Wright Valley showing location of soil profiles (circles and three-digit numbers) and landforms (A through E) discussed In this paper. (Compiled from U.S. Department of Interior Geological Survey topographic maps.)
Map of Wright Valley showing location of soil profiles (circles and three-digit numbers) and iandforms (A through E) discussed in this paper. (Compiled from U.S. Department of Interior Geological Survey topographic maps.)
ANTARCTIC JOURNAL
Table 1. Morphologic properties of soils developed on moraines representative of glaciations in Wright Valley.
Glaciation Trilogy II 111(A) Loop (B) C moraines D moraines Alpine 1 Alpine ha Alpine lIb Alpine III Wright Upper hhI(?) (soil 725) Post-Prospect debris pan (E) Prospect Formation
Depth slightly Depth iceNumber Depth Depth Depth salt coherent Thickness cemented of oxida- ghosts encrusta- consis- salt pan permaprofiles tion (cm) (cm) tions (cm) tence (cm) (cm) frost (cm) 1 2 2 2 6 2 1 4 2 3 1
0 0 0 0 0 0 0 0 0 0 0 8 33 0 0 13 8 42 42 0 14 13 tOO 100 0 35 32 85 85 20 0 0 0 16 0 6 0 23 18 0 8 0 100 50-120 0 32 15-75 125 115 12 65 20 35 110 0
8 28 72 115 105 105 16 75 110 125 122
3 27 38 > 100 > 100 16 100 3 24 8 23 > 100 6 100
Table 2. Surface weathering characteristics of moraines representative of glaciations in Wright Valley.
Glaciation Trilogy I II 111(A) Loop (B) C moraines D moraine segments Alpine! Alpine ha Alpine hIb Alpine III Wright Upper III (?) (soil 725) Post-Prospect debris pan (E) Propect Formation
38
Surface boulder frequency Number (per 314 % fragmented % venti- % cavernously of sites square meters) in situ % planed facts weathered 1 1 1 1 5 1 1 2 3 3 1
248 140 - 84 36 24 - 78 103 6 67
0 0 8 48 66 71 0 1 6 95 43
0 0 0 9 2 4 34 1 38 4 19 33 0 0 7 0 1 0 33 33 46 16
0 2 10 10 19 4 0 60 63 33 9
3
37
68
21 22
12
2
85
42
16 16
29
ANTARCTIC JOURNAL
Table 3. Effect of an advance of the Wright Lower Glacier on morphological properties of soils on Alpine III moraines, Wright Valley.
Profile Location
Approximate Depth Depth salt Salt pan elevation Depth oxida- ghosts encrustations thickness (m) tion (cm) (cm) (cm) (cm)
701 Meserve Glacier, east 702 Meserve Glacier, east 718 Hart Glacier, west 721 Hart Glacier, west
700
53 75 > 112
350
35
65
0
350
28 14 > 85
11
325
18
Table 4. Correlation of moraines in Wright and Taylor Valleys based on soil and rock weathering. Wright Valley Alpine I Trilogy Alpine II
'5 be
cr
'5
Loop C moraines D moraines Alpine!!! Prospect Formation (E)
Taylor Valley Alpine I (II) Ross I Alpine I! (III) Taylor!! Ross II Ross III Taylor III Ross IV Taylor IV -
Increasing age a Symbols in parentheses indicate earlier nomenclature used by Denton and others (1971), but since modified for correlation elsewhere in McMurdo Sound vicinity (Denton, personal communication).
Antarctic search for meteorites during the 1977-78 field season W. A. CASSIDY Department of Earth and Planetary Sciences University of Pittsburgh Pittsburgh, Pennsylvania 15260
Our goals during field season 1977-78 were twofold: (a) to continue collecting meteorites at the Allan Hills site discovered during the 1976-77 field season (Cassidy, 1977; Cassidy et al., 1977; Yanai, 1978); and (b) to reconnoiter October 1978
8
8 > 100
15
0
References
Behling, R. E. 1971. Pedological Development on Moraines of the Meserve Glacier, Antarctica. Unpublished doctoral thesis, The Ohio State University. Bockheim, J . C. 1977. Soil development in the Taylor Valley and McMurdo Sound area. AntarcticJournal of the US., 12(4): 105-108. Denton, G. H., R. L. Armstrong, and M. Stuiver. 1971. The late Cenozoic glacial history of Antarctica. In: Late Cenozoic Glacial Ages (K. K. Turekian, ed.). Yale University Press, New Haven, Connecticut. pp. 297-306. Everett, K. R. 1971. Soils of the Meserve Glacier area, Wright Valley, south Victoria Land, Antarctica. Soil Science, 112: 425-438. Fleck, R. J . , L. M. Jones, and R E. Behling. 1972. K-Ar dates of the McMurdo volcanics and their relation to the glacial history of Wright Valley. Antarctic Journal of the US., 7(6): 245-246. Nichols, R. L. 1971. Glacial geology of Wright Valley. In: Research in the Antarctic (Publication 93, L. 0. Quam, ed.). American Association for the Advancement of Science, Washington, D.C. Vucetich, C. C., And W. W. Topping. 1972. A fiord origin for the Pecten deposits, Wright Valley, Antarctica. New ZealandJournal of Geology and Geophysics, 15(4): 660-673.
other bare ice patches noted on satellite photographs to the west and north of Allan Hills as possible sites of meteorite accumulation. Members of the field party in addition to myself were Billy Glass, Department of Geology, University of Delaware, and Keizo Yanai and Minoru Funaki, National Institute of Polar Research, Tokyo. We were able to carry out detailed foot searches at all major bare ice patches along the western side of Allan Hills, occupying two campsites in different parts of the area (figure 1). We recovered 310 samples in this area and identified 307 of these in the field as meteorites; the other 3 may be terrestrial rocks, but they looked unusual enough that we collected them as possible meteorites. At a third field camp located between the eastern and western "arms" of Allan Hills we found one meteorite on the ice. We visited three patches of bare ice west of the Allan Hills site by helicopter. On two of these we found nothing; but on 39
Armstrong, R L. In press. K-Ar dating: McMurdo volcanics and Dry Valley glacial history, Victoria Land, Antarctica (New Zealand Journal of Geology and Geophysics). Goldich, S. S., S. B. Treves, N. H. Suhr, and J. S. Stuckless. 1975. Geochemistry of the Cenozoic volcanic rocks of Ross Island and vicinity, Antarctica. Journal of Geology, 83: 415-435. Gunn, B. M., and G. Warren. 1962. Geology of Victoria Land between the Mawson and Mulock Glaciers, Antarctica. Bulletin New Zealand Geological Survey, 71: 157. Kyle, P. R., andJ. W. Cole. 1974. Structural control of volcanism in the McMurdo volcanic group, Antarctica. Bulletin Volcanologique, 38(1): 16-25. Kyle, P. R, and P. C. Rankin. 1976. Rare-earth element geochemistry of the McMurdo volcanic group, Antarctica. Geochimica et CosmochimicaActa, 40: 1497-1507. Skinner, D. N. B. In press. Stratigraphy and structure of lower grade metasediments of Skelton Group, McMurdo Sound—Does Teall Greywacke really exist? Proceedings of the Third Symposium on Antarctic Geology and Geophysics, Madison, Wisconsin, 1977.
Soil weathering sequences in Wright Valley J . G. BOCKHEIM
Department of Soil Science University of Wisconsin Madison, Wisconsin 53706
During the 1977-78 field season, I examined soils in Wright Valley to establish their relationship to Wright Lower, Wright Upper, and alpine glaciations and to compare them with soils previously investigated in Taylor Valley (Bockheim, 1977). Detailed descriptions were made for 55 profiles. I collected 295 soil samples and recorded surface weathering features at 28 localities. Laboratory and field methods were described earlier (Bockheim, 1977). Wright Lower Glaciations. Soil properties and surface weathering were examined on moraines of the Trilogy (see figure, location A) and Loop (figure, location B) glacial episodes (Nichols, 1971). Several small, indistinct lateral moraines extending about 100 meters above the Loop Moraine (figure, Cl) and an associated end moraine (figure, C2) 1.6 kilometers west of the Loop Moraine also were examined. Finally, several small, indistinct lateral moraine segments on the north side of the valley 1.5 kilometers west of the C2 end moraine were sampled (figure, D). Soils on the various moraines differ markedly in depths of oxidation, ghosts, salt encrustations, and coherence (table 1). Soils on D moraines feature a salt-cemented horizon averaging 12 centimeters in thickness. In places these soils overlie buried soils derived from a light gray, silty, pulverulent drift 36
which crops out widely further up-valley to the west. Trilogy, Loop, C, and D moraines were distringuished on the basis of surface boulder frequency, fragmentation of boulder in situ, and the extent of cavernous weathering and ventifaction (table 2). Alpine Glaciations. Alpine moraines were examined adjacent to the Goodspeed, Hart, Meserve, and Bartley Glaciers. A sequence similar to that described by Behling (1971) and Everett (1971) was observed. Soil morphology and surface weathering data appear in tables 1 and 2. Alpine I and II soils are similar to Alpine I (II in Denton et al., 1971) and 11(111) soils in Taylor Valley (Bockheim, 1977). However, soils equivalent to Alpine III soils in Wright Valley were not observed in Taylor Valley. This suggests that Alpine III moraines, if they existed in Taylor Valley, were destroyed by the subsequent Taylor IV glaciation(s) or by Ross Sea glaciations. Wright Valley, to the east of Lake Vanda, apparently has not experienced major axial glaciations from the Polar Plateau in the past 4.2 million years (Fleck et al., 1972). A less plausible explanation for the lack of Alpine III moraines in Taylor Valley is that the mechanisms controlling the fluctuations of alpine glaciers in Taylor and Wright Valleys may differ and Alpine III moraines may never have existed in Taylor Valley. The lower portions of Alpine III moraines adjacent to Hart and Meserve Glaciers, and possibly to the Bartley Glacier, have been overridden by advances of the Wright Lower Glacier (table 3). Surface weathering is less on the lower, overridden portions of these lateral moraines. Salt pans, which are common to Alpine III soils above the junction, are conspicuously absent in the portion of the moraine that has been reworked by ice from the Wright Lower Glacier. Wright Upper Glacier. Silt deposits depicted by Vucetich and Topping (1972) as representing the Prospect Formation were examined in detail at three locations: 726, 730, and 734 (figure). Soils derived from the silts have a characteristic light gray (2.5Y 7/2, Munsell soil color chart notation) color, are poorly oxidized, and are pulverulent or powdery. The soils feature a thin (7 centimeter), white, salt-indurated layer just below the surface. Striated diabase cobbles were found within soils 726 and 734. Soils derived from the fine-textured Prospect Formation are poorly developed. However, at Prospect Mesa (figure, E) soils developed in coarser textured debris fan material overlying the Prospect sediments are among the most strongly developed soils that have been examined in Wright Valley (tables 1 and 2). The soils are oxidized to about 25 centimeters, contain ghosts to depths exceeding 25 centimeters, and feature a salt pan at least 15 centimeters thick. Correlation of Wright Valley and Taylor Valley Soils. Using soil properties and surface weathering criteria, moraines of Wright Valley and Taylor Valley are correlated in table 4. The correlations are subject to revision following further field work in Wright Valley and examination of laboratory data. All soil pits were backfilled and the landscape restored to its original conditions as near as possible. This research was supported by National Science Foundation grant DPP 74-20991 to George H. Denton, University of Maine. I am grateful to him for his assistance in locating critical sites for soils investigation, for valuable discussions in the field, and for reviewing this manuscript. A. James Pastene, Ernest F. S. Downes, and Montague Alford assisted in the field work. ANTARCTIC JOURNAL
OLYMPUS RANGE
Tm GLACIER
DAIS
Jr ASGARD RANGE
Map of Wright Valley showing location of soil profiles (circles and three-digit numbers) and landforms (A through E) discussed In this paper. (Compiled from U.S. Department of Interior Geological Survey topographic maps.)
Map of Wright Valley showing location of soil profiles (circles and three-digit numbers) and iandforms (A through E) discussed in this paper. (Compiled from U.S. Department of Interior Geological Survey topographic maps.)
ANTARCTIC JOURNAL
Table 1. Morphologic properties of soils developed on moraines representative of glaciations in Wright Valley.
Glaciation Trilogy II 111(A) Loop (B) C moraines D moraines Alpine 1 Alpine ha Alpine lIb Alpine III Wright Upper hhI(?) (soil 725) Post-Prospect debris pan (E) Prospect Formation
Depth slightly Depth iceNumber Depth Depth Depth salt coherent Thickness cemented of oxida- ghosts encrusta- consis- salt pan permaprofiles tion (cm) (cm) tions (cm) tence (cm) (cm) frost (cm) 1 2 2 2 6 2 1 4 2 3 1
0 0 0 0 0 0 0 0 0 0 0 8 33 0 0 13 8 42 42 0 14 13 tOO 100 0 35 32 85 85 20 0 0 0 16 0 6 0 23 18 0 8 0 100 50-120 0 32 15-75 125 115 12 65 20 35 110 0
8 28 72 115 105 105 16 75 110 125 122
3 27 38 > 100 > 100 16 100 3 24 8 23 > 100 6 100
Table 2. Surface weathering characteristics of moraines representative of glaciations in Wright Valley.
Glaciation Trilogy I II 111(A) Loop (B) C moraines D moraine segments Alpine! Alpine ha Alpine hIb Alpine III Wright Upper III (?) (soil 725) Post-Prospect debris pan (E) Propect Formation
38
Surface boulder frequency Number (per 314 % fragmented % venti- % cavernously of sites square meters) in situ % planed facts weathered 1 1 1 1 5 1 1 2 3 3 1
248 140 - 84 36 24 - 78 103 6 67
0 0 8 48 66 71 0 1 6 95 43
0 0 0 9 2 4 34 1 38 4 19 33 0 0 7 0 1 0 33 33 46 16
0 2 10 10 19 4 0 60 63 33 9
3
37
68
21 22
12
2
85
42
16 16
29
ANTARCTIC JOURNAL
Table 3. Effect of an advance of the Wright Lower Glacier on morphological properties of soils on Alpine III moraines, Wright Valley.
Profile Location
Approximate Depth Depth salt Salt pan elevation Depth oxida- ghosts encrustations thickness (m) tion (cm) (cm) (cm) (cm)
701 Meserve Glacier, east 702 Meserve Glacier, east 718 Hart Glacier, west 721 Hart Glacier, west
700
53 75 > 112
350
35
65
0
350
28 14 > 85
11
325
18
Table 4. Correlation of moraines in Wright and Taylor Valleys based on soil and rock weathering. Wright Valley Alpine I Trilogy Alpine II
'5 be
cr
'5
Loop C moraines D moraines Alpine!!! Prospect Formation (E)
Taylor Valley Alpine I (II) Ross I Alpine I! (III) Taylor!! Ross II Ross III Taylor III Ross IV Taylor IV -
Increasing age a Symbols in parentheses indicate earlier nomenclature used by Denton and others (1971), but since modified for correlation elsewhere in McMurdo Sound vicinity (Denton, personal communication).
Antarctic search for meteorites during the 1977-78 field season W. A. CASSIDY Department of Earth and Planetary Sciences University of Pittsburgh Pittsburgh, Pennsylvania 15260
Our goals during field season 1977-78 were twofold: (a) to continue collecting meteorites at the Allan Hills site discovered during the 1976-77 field season (Cassidy, 1977; Cassidy et al., 1977; Yanai, 1978); and (b) to reconnoiter October 1978
8
8 > 100
15
0
References
Behling, R. E. 1971. Pedological Development on Moraines of the Meserve Glacier, Antarctica. Unpublished doctoral thesis, The Ohio State University. Bockheim, J . C. 1977. Soil development in the Taylor Valley and McMurdo Sound area. AntarcticJournal of the US., 12(4): 105-108. Denton, G. H., R. L. Armstrong, and M. Stuiver. 1971. The late Cenozoic glacial history of Antarctica. In: Late Cenozoic Glacial Ages (K. K. Turekian, ed.). Yale University Press, New Haven, Connecticut. pp. 297-306. Everett, K. R. 1971. Soils of the Meserve Glacier area, Wright Valley, south Victoria Land, Antarctica. Soil Science, 112: 425-438. Fleck, R. J . , L. M. Jones, and R E. Behling. 1972. K-Ar dates of the McMurdo volcanics and their relation to the glacial history of Wright Valley. Antarctic Journal of the US., 7(6): 245-246. Nichols, R. L. 1971. Glacial geology of Wright Valley. In: Research in the Antarctic (Publication 93, L. 0. Quam, ed.). American Association for the Advancement of Science, Washington, D.C. Vucetich, C. C., And W. W. Topping. 1972. A fiord origin for the Pecten deposits, Wright Valley, Antarctica. New ZealandJournal of Geology and Geophysics, 15(4): 660-673.
other bare ice patches noted on satellite photographs to the west and north of Allan Hills as possible sites of meteorite accumulation. Members of the field party in addition to myself were Billy Glass, Department of Geology, University of Delaware, and Keizo Yanai and Minoru Funaki, National Institute of Polar Research, Tokyo. We were able to carry out detailed foot searches at all major bare ice patches along the western side of Allan Hills, occupying two campsites in different parts of the area (figure 1). We recovered 310 samples in this area and identified 307 of these in the field as meteorites; the other 3 may be terrestrial rocks, but they looked unusual enough that we collected them as possible meteorites. At a third field camp located between the eastern and western "arms" of Allan Hills we found one meteorite on the ice. We visited three patches of bare ice west of the Allan Hills site by helicopter. On two of these we found nothing; but on 39
