Artesian well at Don Juan Pond steady rate of 4 liters per ...Jurassic tholeiltic rocks from the...
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10 it Mt Faila 9 .9 *Pointed Cliffs 0 Ot.y Massif C*00*I Tronsantorctic Mountains 0 a Grosvenor MO Other 7 D North Victoria Land South Victoria Land 0 Caron Glacier 1 • .1 9(99*, Eo,po.ot D. . . •0 0 0'O.9Q Maud Land 4 2 A D0p I 0 (09 A DD 0 -50 52 54 :. 58 60 Q 14 lo 72 Sn2 Figure 3. Silica variation diagrams of selected oxides for Jurassic tholeiltic rocks from the Transantarctic Mountains. determined, but an intrusive origin appears to be the most likely method. Over 150 new major element analyses (figure 3) of Jurassic tholeiites from Antarctica will provide a data base for more specialized geochemical studies. In the course of our 1978-79 fieldwork, we also dis- covered that Elephant Nunatak (unofficial name), a fea- ture east of Reckling Peak previously discovered using satellite imagery, is composed entirely of moraine. In addition, we found five chondrite meteorites in the vi- cinity of the moraine. I was supported in the field by Kathy Cashman and Harry Keys (both from Victoria University of Welling- ton) and Bill McIntosh (University of Colorado). This work has been supported by National Science Founda- tion grant DPP 77-21590. References (;rn, B. M. 1966. Modal and element variation in Antarctic tholeiites. Geochimica Cosmochimica Acta, 30: 881-920. Kyle, P. R. Development of heterogeneities in the subcontinen- tal mantle: Evidence from the Ferrar Group, Antarctica. In Contributions to Mineralogy and Petrology (in press). Skinner, D.N.B., and J . Ricker. 1968. The geology of the re- gion between the Mawson and Priestley Glaciers, north Vic- toria Land, Antarctica. New Zealand Journal of Geology and Geophysics, 11: 1009- 1075. Artesian well at Don Juan Pond LYLE D. MCGINNIS Department of Geology Northern Illinois University De Kalb, Illinois 60115 Don Juan Pond, located in the suth fork of Wright Valley, was revisited on 9-12 December 1978 to observe the status of Dry Valley Drilling Project (DVDP) hole 13. Since its drilling on 8-13 January 1975, the borehole and pond have remained under intermittent observation (Harris and Cartwright, in press; Harris, Cartwright, and Toni, 1979). The borehole is unusual in that it contains unfrozen, concentrated brines near 200 parts per thousand. Water level in the borehole is responding to episodic, impulsive pressure changes of unproven origin (Harris and Cart- wright, in press). Plans are under way to install auto- matically recording instrumentation at the borehole to determine the cause of the transient pressure variations and the source of the brines. After ice was cleared from the upper 10 meters of the hole at 1700 hours on 9 December, water at a temper- ature of - 15.50 C began flowing from the hole at a steady rate of 4 liters per minute and continued to flow for three days before being shut off. Casing set through the sand overburden (see figure) stands 0.70 meter above ground surface and about 1 meter above Don Juan Pond. It is believed that water is flowing from the fractured and highly mineralized Ferrar dolerite, which acts as a confined aquifer in the dry valleys but may receive its water from subglacial lakes at the base of the Antarctic Ice Sheet. Geophysical logs of the borehole are also shown in the accompanying figure. A discussion of the logs is pro- vided in McGinnis et al. (in press). This study has been supported by the Division of Polar Programs of the National Science Foundation, grant number DPP 7821112-01. References Harris, H. J . H., and K. Cartwright. In press. Pressure fluctua- tions in an antarctic aquifer: The freight train response to a moving rock glacier. In Third Symposium on Antarctic Geology and Geophysics, ed. C. Craddock. Madison: University of Wisconsin Press. Harris, H. J . H., K. Cartwright, and T. Toni. 1979. Dynamic chemical equilibrium in a polar desert pond: A sensitive index of meteorological cycles. Science, 264(4390): 301-3. McGinnis, L. D., J . S. Stuckless, D. R. Osby, and P. R. Kyle. In press. Gamma-ray, salinity, and electric logs of DVDP bore- holes. In Dry Valley Drilling Project, ed. L. McGinnis. Ant- arctic Research Series. Washington, D. C.: American Geo- physical Union. 26
Transcript of Artesian well at Don Juan Pond steady rate of 4 liters per ...Jurassic tholeiltic rocks from the...
10 it Mt Faila
9.9 *Pointed Cliffs
0 Ot.y MassifC*00*I Tronsantorctic Mountains0 a Grosvenor MO
Other7D North Victoria Land
South Victoria Land
0 Caron Glacier
1
• .1 9(99*, Eo,po.otD..
.•0 0 0'O.9Q Maud Land4
2 AD0p
I 0
(09 A
DD
0 -505254:.5860Q14 lo72
Sn2
Figure 3. Silica variation diagrams of selected oxides forJurassic tholeiltic rocks from the Transantarctic Mountains.
determined, but an intrusive origin appears to be themost likely method.
Over 150 new major element analyses (figure 3) ofJurassic tholeiites from Antarctica will provide a data
base for more specialized geochemical studies.In the course of our 1978-79 fieldwork, we also dis-
covered that Elephant Nunatak (unofficial name), a fea-ture east of Reckling Peak previously discovered usingsatellite imagery, is composed entirely of moraine. Inaddition, we found five chondrite meteorites in the vi-cinity of the moraine.
I was supported in the field by Kathy Cashman andHarry Keys (both from Victoria University of Welling-ton) and Bill McIntosh (University of Colorado). Thiswork has been supported by National Science Founda-tion grant DPP 77-21590.
References
(;rn, B. M. 1966. Modal and element variation in Antarctictholeiites. Geochimica Cosmochimica Acta, 30: 881-920.
Kyle, P. R. Development of heterogeneities in the subcontinen-tal mantle: Evidence from the Ferrar Group, Antarctica. InContributions to Mineralogy and Petrology (in press).
Skinner, D.N.B., and J . Ricker. 1968. The geology of the re-gion between the Mawson and Priestley Glaciers, north Vic-toria Land, Antarctica. New Zealand Journal of Geology andGeophysics, 11: 1009- 1075.
Artesian well at Don Juan Pond
LYLE D. MCGINNIS
Department of GeologyNorthern Illinois University
De Kalb, Illinois 60115
Don Juan Pond, located in the suth fork of WrightValley, was revisited on 9-12 December 1978 to observethe status of Dry Valley Drilling Project (DVDP) hole 13.Since its drilling on 8-13 January 1975, the boreholeand pond have remained under intermittent observation(Harris and Cartwright, in press; Harris, Cartwright,and Toni, 1979).
The borehole is unusual in that it contains unfrozen,concentrated brines near 200 parts per thousand. Waterlevel in the borehole is responding to episodic, impulsivepressure changes of unproven origin (Harris and Cart-wright, in press). Plans are under way to install auto-matically recording instrumentation at the borehole todetermine the cause of the transient pressure variationsand the source of the brines.
After ice was cleared from the upper 10 meters of thehole at 1700 hours on 9 December, water at a temper-ature of - 15.50 C began flowing from the hole at a
steady rate of 4 liters per minute and continued to flowfor three days before being shut off. Casing set throughthe sand overburden (see figure) stands 0.70 meterabove ground surface and about 1 meter above DonJuan Pond. It is believed that water is flowing from thefractured and highly mineralized Ferrar dolerite, whichacts as a confined aquifer in the dry valleys but mayreceive its water from subglacial lakes at the base of theAntarctic Ice Sheet.
Geophysical logs of the borehole are also shown in theaccompanying figure. A discussion of the logs is pro-vided in McGinnis et al. (in press).
This study has been supported by the Division of PolarPrograms of the National Science Foundation, grantnumber DPP 7821112-01.
ReferencesHarris, H. J . H., and K. Cartwright. In press. Pressure fluctua-
tions in an antarctic aquifer: The freight train response toa moving rock glacier. In Third Symposium on Antarctic Geologyand Geophysics, ed. C. Craddock. Madison: University ofWisconsin Press.
Harris, H. J . H., K. Cartwright, and T. Toni. 1979. Dynamicchemical equilibrium in a polar desert pond: A sensitiveindex of meteorological cycles. Science, 264(4390): 301-3.
McGinnis, L. D., J . S. Stuckless, D. R. Osby, and P. R. Kyle. Inpress. Gamma-ray, salinity, and electric logs of DVDP bore-holes. In Dry Valley Drilling Project, ed. L. McGinnis. Ant-arctic Research Series. Washington, D. C.: American Geo-physical Union.
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RESISTIVITY
NATURALGAMMA RADIATION IN
COUNTS/SEC102030405060irr Tmw- rAewn T( A rDrLJ (2 A
ffffl-70809( 0102030
10
20
30Cl)
UjluI-
40
a.I—w0 50
60
70
80
In ¼II.J..JtW
0.0762 m\
s-. (x 3048)
Nt . 3.0480m •
' y (x 12.19)
0.7620m
t304+ eel —
4. I S
N11
1- I•__-••-,- - .-.
j-'-'I'.)
%..-.'..I *5•,
AAjLA
I,. •
Li1 Pebbles, sand and silt
I-J Ferrar Dolerite
Gneiss
Resistivity and natural radioactivity logs at DVDP 13 in the Don Juan Pond basin. Multiply the number in parentheses by thenumbers on the horizontal scale to get resistivity in ohm-meters. The numbers 0.0762, 0.7620, and 3.0480 Indicate the distanceIn meters between the potential electrodes and the current electrode. The 0.0762 meter readings are a measure primarily of
the resistivity of the fluid In the borehole; the 3.0480 meter readings are primarily "formation" resistivity.
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