The UNIVERSITY of WISCONSIN

Geophysical & Polar Research Center'-

DEPARTMENT OF GEOLOGY

SUMMARY AND DISCUSSION OF THE GEOPHYSICAL AND GLACIOLOGICAL WORK IN THE FILCHNER ICE SHELF AREA OF ANTARCTICA

by John C. Behrendt

RESEARCH REPORT NO. 62.3-APRIL, 1962

Research Report Series Number 62-3 April 1962

SUMMARY AND DISCUSSION OF THE GEOPHYSICAL AND GLACIOLOGICAL WORK IN THE FILCHNER ICE SHELF AREA OF ANTARCTICA

by John C. Behrendt

The University of Wisconsin Geophysical and Polar Research Center 6021 South Highland Road The Highlands Madison 5, Wisconsin PREFACE

This report contains a previously published discussion of the cal and glaciological geophysi- work on the Filchner ice shelf (Behrendt, 1962) to- gether with a tabulation of data and photo copies of representative seismic records for each of the reflection stations. ABSTRACT

Geophysical and glaciological data collected during the IGY in the Filchner ice shelf area have been reported previously, and some of the se are included here to present a more unified picture of the region. A large trough underlies the eastern section of the ice shelf and extends into the unexplored area at its head. Although the trough is not iso- statically compensated locally, the area as a whole is essentially in isostatic equilibrium. The elevation of the M discontinuity is about -31 kin, which is consistent with that expected for a continental margin, Berkner island is a grounded ice feature on Berkner bank, which gravity data indicate is probably composed of morainal material. The eastern section of the shelf is flowing seaward at a high rate, and the amount of ice lost at the ice front is greater than accumulation on the shelf,

I I I CONTENTS

Page Introduction ...... * * . 1

...... • . • . • . • Gravity Data Reduction ......

. . . . • ...... • . . • . Presentation of Results .... 6

...... • . • . • . • Discussion of Geophysical Results 6

. Crustal Studies ...... 16

• • ...... • ... • . Ice Shelf Regimen . ... 17

• • ...... • . Conclusions...... 19

. . •...... • . Acknowledgments 20

...... • ...... • . References...... 21

Appendix I ...... 23 Appendix II ...... 42

ILLUSTRATIONS

Page Figure 1. Filchner ice shelf traverse route ...... 2 Figure 2. Ellsworth to Dufek massif, profile of principal facts . . 4 Figure 3. Dufek massif to Korff island, profile of principal facts 5 Figure 4. Bedrock elevation, Filchner ice shelf area ...... 7 Figure 5. Surface elevation, Filchner ice shelf area ...... 8 Figure 6. Ice thickness, Filchner ice shelf area...... 9

Figure 7. Free-air anomalies, Filchner ice shelf area ... 10 Figure 8. Reduced free-air anomalies, Filchner ice shelf area . . 11

Figure 9. Bouguer anomalies, Filchner ice shelf area ...... 12 Figure 10. Echo sounder profile, Bowman peninsula to Moltke nunatak 13 Figure 11. Comparison of AsG vs. Adepth ...... 15

Table 1. Seismic Results ...... INTRODUCTION

Preliminary reports on the geography, sub-ice topography, and seismic, gravity, magnetic, and glaciological measurements carried out in the Filch- ner ice shelf area of Antarctica during the International Geophysical Year have been presented respectively by NeuburR, Thiel, Walker. Behrendt, and Auqhenbaugh (1959), Behrendt and Thiel (1959), Thiel and Behrendt (1959a, b, c) Aughenbaugh, Neuburg, and Walker (1958). In the present paper an attempt is made to integrate much of the published and unpublished materi- al collected during the IGY in order to present a unified picture of the Filchner ice shelf and its surroundings.

Most of the data were gathered by the Ellsworth traverse party at Ells- worth station and on a 2100-km trek into the interior of the ice shelf during the austral summer of 1957-1958. Seismic and glaciological measurements were made at intervals of 40 to 50 km, and gravity, magnetic, and elevation obser- vations were made every 8 km. Figure 1 illustrates the traverse route and the locations of the seismic stations. Names marked with an asterisk have not yet been acted on by the Board of Geographic Names. Discussions of field pro- cedures and preliminary data reduction may be found in the above references.

Ice thicknesses were calculated from seismic data, making allowances for near-surface low velocities and using a maximum P wave velocity of 3810 m/sec (Thiel and Behrendt, 1959f). At ice shelf stations a velocity of 1445 m/sec was used for the water section of the reflection path. At a few stations PS or SS reflections were obtained from the ice-water interface, permitting cal- culation of shelf thickness using an S wave velocity of 1910 m/sec (Thiel and Behrendt, 1959a).

At most stations no reflection was obtained from the base of the float- ing ice, so the shelf thickness was calculated from the surface elevation using curves presented by Thiel and Ostenso (1961). Values obtained by the two methods agreed fairly well at stations where reflections from the ice- water interface were observed. The standard deviation in absolute elevation estimated from the reoccupation of six stations is + 18 m; relative errors between neighboring stations are probably much smaller. A positive error of 18 m in elevation would cause an error in ice thickness of +180 m and in depth to the sea floor of +110 m.

Table 1 shows the vertical travel times, ice thickness, depth to bed- rock (i.e., sediments, till, or actual rock), and attitude of bedrock for the traverse stations. The reflection results are plotted along with other data in the profiles in Figures 2 and 3 and will be discussed more fully in a later section.

Gravity Data Reduction A Frost low-drift gravimeter was used for the traverse observations. The base station at Ellsworth was tied to the world network in February 1959 using LaCoste and Romberg geodetic gravimeter No. 1; this instrument had a drift rate of 1 mgal/month and a world range (Behrendt and Woollard, 1961). Fig. 1. Filchner ice shelf traverse route. I m

TABLE I Seismic Results

Seismic Reflection Surface Ice Rock Attitude of Station Time. Elevation, Thickness, Elevation Rock Surface sec. +18 meters meters +40 meters Dip Strike

1 0.995 42 230 - 790 40S E -W 2 1.152 69 470 -1040 20 N N 520 W 3 1.349 72 500 -1200 4*E N 34 0 E 4 1.086 80 570 -1040 3*N N 72 0 W lS 5 1.124 73 510 -1040 N 750 W 6 1.359 86 620 -1270 4*E N 18OW 7 NR 74 520 -1010* 8 .355 599 680 - 80 4*E N 18 0 2*SW W 9 . 448 694 850 - 160 NW- SE 10 NR 153 660 - 240*

11 1.014 81 580 -1000 4*W N 70 W 12 1.334 96 670 -1270 6N E -W 13 1.382 90 660 -1310 4*N E -W 14 NR 275 400 - 610* 15 .212 523 400 - 120 230 W N 34"E 16 1.633 129 1040 -1680 7*W N 30*W 17 1.242 158 1310 -1540 40 E N 15 0 W 18 .866 131 1050 -1130 20 W N 360W 19 .461 224 850 - 630 20 NR 78 550 - 580* 21 .487 82 590 - 620 40 E N 60 W low 22 .462 77 540 - 580 N 220 E 23 .498 64 420 - 550 2 0 E N 22 0 W 24 ,300 400 570 - 170 0 25 NR 57 360 - 700* 0 26 .401 162 760 - 600 5 E N 36"W 27 .948 105 800 -1060 4*E N 14 0 E

Gravity-determined rock elevation. +50 MGL. -r

0

-50 MGL. + IOOMGL.

i +50 MGL.-

+1000 M.- I 3 4

0 M.- ICE -*0

-1000 SEA M. WhTER

ROCK

BERKNER ISLAND OUFEK MASSIF

Fig. 2. Ellsworth to Dufek massif, profile of principal facts.

I-- I -

+50 MGL.

-50 MGL. 4IOOMGL.

"+50MGL.-

+ 1000 M.- 1 11 is19 214 220

. 0 M.

-1000 Iw

DUFEK MASSIF MALVILLE PENINSULA KORFF 151AND

Fig. 3. Dufek massif to Korff island, profile of principal facts. 6

Free-air anomalies were calculated for the 224 field stations. The Bouguer anomaly calculated at each seismic station included appropriate corrections for mass deficiencies between sea level and bedrock, assuming densities of 2.67, 0.9, and 1.03 g/cm3 for rock, ice, and water, respectively.

In calculating the depth to bedrock for each gravity station free-air corrections were made for stations on floating ice, and free-air corrections, adjusted by a Bouguer correction from snow surface to sea level, were made for stations on grounded ice. Density differentials of 1.64 g/cm3 for water- rock and 1.77 g/cm3 for ice-rock give ratios of change in rock elevations to change in gravity of 14.6 and 13.5 m/mgal, respectively. The use of seismic reflection depths for control helped to eliminate errors caused by incorrect assumed density, terrain irregularities, or geologic change at depth.

Presentation of Results Figures 2 and 3 show ice surface elevations, ice thicknesses, rock sur- face elevations, free-air anomalies, and Bouguer anomalies for the stations on the three legs of the traverse. These results have also been plotted on maps (Figs. 4-9) and contoured in an attempt to reveal some areal signifi- cance.

In addition to the data from the Ellsworth traverse upon which most of this work is based, soundings from every other available source have been used, including two depths from the Ellsworth-Byrd 1958-1959 traverse, many from the ships Wyandot, Staten Island, and Edisto, extending over the period 1956-1959, and several from the Deutschland in 1912 (Filchner, 1922) and the Endurance in 1915 (Shackleton, 1919). Even with all the data available, the paucity of information has necessitated much extrapolation.

Discussion of Geophysical Results The most striking feature of the profiles in Figures 2 and 3 is the deep trough underlying the thick ice of the eastern section of the Filchner ice shelf. This appears to start somewhere to the southwest of the profile from Dufek massif to Malville peninsula. The bottom is about 1700 m deep near sta- tion 16, rising to around 1200 m along the ice front (Figs. 4 and 10). The ice shelf to the west of Berkner island overlies much shallower water (Figs. 3 and 4); the grounded ice of Malville peninsula is located at the junction of the thick ice to the east and this shallow bottom to the west.

Figure 4 shows that Berkner island is a relatively small patch of grounded ice on a huge shoal or bank which extends hundreds of kilometers to the edge of the continental slope in the Weddell Sea. It is proposed here that theI name Berkner should include this bank. There is a suggestion of deep water near the western edge of the shelf, but data are not sufficient to permit us to determine its extent. Possibly there are more grounded ice islands or peninsulas in the unexplored area between the western edge of Berkner island and the Orville escarpment.

The profiles and gravity maps (Figs. 2, 3, 7, 8, and 9( show a general relationship between free-air anomalies and topography, as might be expected for features too small in extent to have total isostatic compensation. A - -m-m mm- -I=- -m-o I--

Fig. 4. Bedrock elevation, Filchner ice shelf area. 00

N ELLS OTH STATION I 820~.

006

FILCHNER ICE SHELFA K./SURFACE ELEVAT "M IN METERS 3-SO.

606 500 400 30' 820 so*

Fig. 5. Surface elevation, Filchner ice shelf area. m --- m m =-=n m -m- --- I ml

Fig. 6. Ice thickness, Filchner ice shelf area. I?E STAMMO o -. tr-

Alp

Fig 7.Fre ainmle•icne c hl ra

' 40* .40 3* Fig.7.aomales, Fee-ar ilcher ce self,rea

M - OIM ONMIN-I-MIN-N I-I--- I- -- - I-- - - =-=m= - =------=mI-- I m

Fig. 8. Reduced free-air anomalies, Filchner ice shelf area. Fig. 9. Bouguer anomalies, Filchner ice shelf area.

I------I--

BOWMAN MOLTKE PENINSULA MUNATAK

ELLSWORTH o

------. SAEE :._. :: -5o .41.f.t: : !:"-.

Fig. 10. Echo sounder profile, Bowman peninsula to Moltke nunatak. 14

gravity low is associated with the trough, and a high exists where the ice is grounded and above sea level. The Bouguer map shows a positive anomaly associated with the trough.

Tsuboi (1950), calculated a 160-km limit of regionality for isostatic compensation of topographic expressions. Features of smaller extent than this are supported not isostatically but by the finite strength of the crust. The trough under discussion is about 140 km wide; thus, some quantitative analysis was necessary before anything could be concluded about the extent of isostatic compensation. The bank is certainly large enough to be consid- ered compensated.

An attempt was made to learn whether partial local isostatic compensa - - tion is the cause of the observed anomaly over the trough. Talwani, Sutton, and Worzel (1959) used a two-dimensional method of computing isostatic anom- alies over the Puerto Rico trench. Using their method as an approximation, the isostatic anomalies over the trough were found to average about 40 mgal less than the anomalies over the bank, indicating that the trough is not completely compensated when compared with the bank.

The amount of isostatic compensation associated with the trough was next analyzed. If the trough were in perfect isostatic equilibrium, the Bouguer anomaly which should be associated with it could be calculated. The depth to the mantle was computed for various sections of the trough and bank on the basis of elevation (Woollard, 1959). The attraction of the mass between an assumed standard depth of 34 km and the computed depth was calculated, assuming a density differential of 3.26 - 2.80 = 0.46 g/cm3 between the crustal base and the upper mantle. This correction is equal to the 'theoretical' Bouguer anomaly. The anomalies thus determined were com- pared with the Bouguer anomalies actually observed. The Bouguer anomalies southward along the trough average about +60 mgal for the four profiles across it, and the 'theoretical' Bouguer anomalies average approximately +90 mgal. From this, the trough appears to be about two-thirds compensated.

The theoretical and observed Bouguer anomalies over the bank were ap- proximately the same, indicating that this area is essentially in isostatic equilibrium.

The density of the material composing the bank was next considered, Since the Bouguer anomalies represent the isostatic compensation present over large areas, it was possible to eliminate this effect for studying the boundary between the trough and bank by assuming that the difference in Bou- guer anomaly between typical central areas of the trough and bank could beI spread linearly over the interval. The isostatic gravity gradient thus com- puted was used to adjust the difference between the free-air anomalies (re- duced free-air anomaly, for grounded ice) for pairs of closely spaced seis- mic stations. It was then assumed that the free-air gravity difference be-I tween two such stations was due entirely to the difference in mass under the deeper (trough) station and the shallower (bank) station. A graph of differ- ence in gravity versus difference in depth of bedrock was plotted for several pairs of stations along the boundary of the trough and is shown in Figure 11. ------=I I n

C,,

I

0 200 400 600 800 1000 1200 1400 1600

Ak DEPTH IN METERS

FIG. II. COMPARISON OF AG VS. A DEPTH 16

Theoretical lines for the densities p = 2.0 g/cm3 and p 2.67 g/cm3 are shown for reference. Seven of the nine points appear to be definitely lower than p = 2.67 g/cm 3 , corresponding to an average of p = 2.0 g/cm3 . The two anom- alous points with densities of about p = 2.67 g/cm3 are associated with Korff island at the northwesternmost extremity of the traverse (station 24) and with the southernmost part of Berkner island (station 9).

If the anomalous points are ignored, it seems evident that there is a bank or shoal of material with an average density of about 2.0 g/cm 3 bordered by the approximately 1200-m-deep trough. On the basis of density alone (Hei- land, 1946) this might be sediment or drift.

Taylor (1930) discussed the unusually deep continental shelf around Ant- arctica and noted that exceptions are the Pennell bank off the Ross ice shelf and a shallow area off the Shackleton ice shelf. He speculated that these might be terminal moraines. Evteev (1959) discussed the morainal material transported by the ice in the Mirny area in East Antarctica and concluded that the ice has a great capacity for load carrying. Crary (1961 b), in dis- cussing the approximately 1300-m-thick sediment layer beneath the Little Amer- ica area of the Ross ice shelf, stated that most of it may have been deposited by ice.

Evidence in the Ross Sea and Filchner ice shelf areas indicates that the ice was much higher at one time. The present ice level in the Dufek massif is over 300 m below summits at the eastern end of the range which show evi- dence of past glaciation. Since it would require only about 400 m more ice to ground the Filchner ice shelf over the trough, and much less over the bank, I it is proposed that the bank and trough were formed by glacial action at a time when the ice sheet extended over the area of the present shelf to the Weddell Sea. It will be shown in the section on ice shelf regimen that the eastern half of the Filchner ice is flowing at a high rate, probably much faster than the western section. It seems possible that the relative motion may have been similar when the shelf was grounded, or that the major zone of movement slowly changed as the bank of morainal material built up, until the ice flowed mainly in a channel corresponding to the trough.

The high-density point corresponding to station 9 in the southeast area of Berkner island (Fig. 11) suggests bedrock rather than moraine at the base of the ice. Such a topographic feature might have greatly influenced the formation of the bank and defined the morphology of the trough by its effectI on the flow of the ice.

Korff island at station 24 also is probably underlain by bedrock, as shown in Figure 11. Figure 4 shows that this area is separated from the main portion of the bank by deep water and is fairly near a nunatak, pre- sumably on the Antarctic Peninsula. The high quality of the reflection ob- tained at station 24 as compared with the stations over the bank substanti-I ates the probable presence of bedrock.

Crustal Studies H Free-air gravity anomalies are a first approximation to isostatic anom- alies. Examination of the free-air anomaly map shows the range to be from 17

+4 mgal on Berkner island to -50 mgal over the trough and the average to be -11 mgal over the whole area. Isostatic anomalies, calculated as described previously, are in substantial agreement. The areas showing the anomaly ex- tremes, such as the trough, are too small or too recent to be completely com- pensated isostatically, but the area as a whole seems to be in isostatic equilibrium.

Woollard (1959) presented curves for computing crustal thickness based on Bouguer anomalies and Archimedes' principle, assuming that isostasy is achieved on a regional basis. Adjusted elevations were computed by convert- ing known density material and water to p = 2.67 g/cm3 , and lowering or rais- ing the elevation of the surface or sea bottom accordingly. His recent ad- justment of the curves to a sea level crustal column of 34 m (paper in pre- paration) was taken into consideration in the present work.

These adjusted elevations were averaged for stations over Berkner bank, which was assumed to be essentially in isostatic equilibrium by virtue of its large area. Elevations of the M discontinuity were then taken from Woollard's curve° The bank appears to overlie a crust extending to a depth of approxi- mately 32.5 km. As would be expected, the M discontinuity becomes progres- sively deeper as the Pensacola Mountains are approached and is at an elevation of about -35 km in the area of the Dufek massif. Indications of crustal depths approaching 36 to 40 km in the Pensacola Range are obtained by estimating ele- vations.

The Bouguer anomalies for all the bank stations averaged +30 mgal, which corresponds to an elevation of the M discontinuity of -31 km, approximately 1.5 km shallower than that determined from elevations. In the computation of the adjusted elevations the bedrock was assumed to be of density p = 2.67 3 g/cm . In the previous section it has been shown that the bank itself is probably composed of moraine with a density of about p = 2.0 g/cm 3 . Eleva- tions were recomputed allowing for a morainal bank 600 m thick; this raised the depth to the M discontinuity to the same value obtained from the Bouguer anomalies. Thus, we have further evidence of the low-density material in the bank.

The adjusted elevations and Bouguer anomalies for the trough area indi- cate an elevation of the M discontinuity of -28 km, or about 3 km shallower than the bank area. It has been shown in the preceding sections, however, that the trough is only about two-thirds isostatically compensated, which means that the discontinuity should be somewhat deeper than -28 km beneath the trough.

The above calculations show a crustal thickness typical of a continental shelf area (Ewing and Press, 1955). If the ice were removed, the whole area would rise somewhat but would still have its surface below the sea. The edge of the continental shelf of Antarctica is about 500 m deep, instead of 200 m as is typical of the other continents. The greater depths are possibly caused by ice loading.

Ice Shelf Regimen It will be shown in this section that despite large uncertainties in the existing data, it may be concluded that more ice is lost at the Filchner ice 18

front than accumulates on the ice shelf. The difference can be accounted for by the influx ice from the high plateau of East Antarctica.

Glaciological studies of the Ellsworth area (Aughenbaugh, Neuberg, and Walker, 1958; Goodwin, 1959; and Giovinetto, 1961) give a weighted mean accu- mulation of 21 cm/yr water equivalent with a standard deviation of 5 cm. Al- though the melting at the base of the Ross ice shelf is about 80 cm/yr (Crary, 1961A), level lines surveyed at Ellsworth (Aughenbaugh, Neuberg, and Walker, 1958) six months apart showed no evidence of any thinning. The error in the leveling is not known but is probably a few centimeters. The only conclusion possible is that any change in thickness is less than a few tens of centimeters.

Astronomical position determinations (Aughenbaugh, Neuberg, and Walker, 1958; Lisignoli, personal communication; Antarctic, 1961) indicate a northward component of movement of the ice shelf of 1.3 km/yr at Ellsworth and 2.6 km/yr at Belgrano. Wexler (1960) calculated a movement rate of 2 km/yr for the Filch- ner ice shelf from temperature studies.

Using an average thickness of 0.25 km, a mean density of 0.84 g/cm3 along the 240-km ice front east of Berkner island, and an estimated velocity of 2 km/yr, we obtain 100 km3/yr of water discharge into the Weddell Sea. It would require 60 cm/yr of surface accumulation over the eastern ice shelf (areal ex- tent, 16 x 105 km2) to account for this flow. Giovinetto (1961) gives an average of 17 + 2 cm/yr for this section of the ice shelf, leaving over 40 cm/yr or a total volume of 60 km3/yr to be accounted for.

A photograph (Aughenbaugh, 1958) of the unexplored area between the Pen- sacola and Horlick mountains at the head of the ice shelf shows what appears to be a large ice stream flowing down from the hinterland of East Antarctica. In January 1961 a large valley in the ice surface about 700 m deep was dis- covered, south of the high ice dammed up by the Horlick Mountains (Behrendt, Wold, and Dowling, in press). This was observed to trend downhill in the direction of the Filchner ice shelf and is probably an expression of a rapid ice flow.

Ice thicknesses measured on the plateau areas of Antarctica range from 2 to 4 km (Bentley and Ostenso, 1961). The ice measured on the ice shelf near its upstream end was 1.3 km thick. On the basis of these figures, a minimum thickness of 1.3 km was assumed for the 200-km-wide ice stream be- tween the Horlick and Pensacola mountains. This ice stream would have toI move 70 cm/day to account for the 60-kmn3 excess discharge at the ice front. This rate is within the range of movement for antarctic ice streams discussed by Mellor (1959). The ice is probably thicker than 1.3 kin, and the Recovery and Slessor glaciers (40 and 60 km wide, respectively) certainly carry a large amount of ice into the shelf; this calculation does show, however, that the excess discharge at the ice front can be balanced by reasonable flow rates from the interior ice sheet. Using a mean accumulation rate for the high in- land ice of 10 cm/yr water equivalent (Lister, 1959; Kotlyakov, 1960), an area of 6 x 105 kin2 , four times as large as the eastern Filchner ice shelf, is needed to account for the excess of 60 km3 /yr.

If the movement rate at the ice front were only the minimum observed value of 1.3 km/yr instead of 2, and if the shelf thickness were only 200 m, or less 19

than that observed anywhere along the ice front, there would still be twice as much ice flowing out as is accumulating on the surface. If there is sig- nificant melting on the bottom, as occurs under the Ross ice shelf (Crary, 1961), even more surface accumulation would be required for mass balance.

Conclusions We have shown the following by analysis and interpretation of geophysi- cal, geographical, and glaciological data collected in the Filchner ice shelf area of Antarctica.

1. The eastern portion of the ice shelf is underlain by a deep trough extending into the unexplored area at the head of the shelf.

2. Berkner island and the adjacent Malville peninsula are grounded ice features on Berkner bank, a vast area extending far out into the Weddell Sea. Analysis of the gravity data shows this bank to be composed of a low-density material, probably morainal.

3. Berkner bank and the trough may have been formed simultaneously by glacial action at a time when the ice was several hundred meters thicker than at present and was consequently grounded. The extent of this ice is probably represented by the 500-tm isobath in the Weddell Sea.

4. The morphology of Berkner bank is possibly controlled by a topographic rise in bedrock of unknown dimension in the southeast part of Berkner island. Korff island appears to be underlain by bedrock which is probably associated geologically with a nunatak a short distance to the west.

5. The area beneath Berkner island and the western part of the Filchner ice shelf is essentially in isostatic equilibrium, and the thickness of the earth's crust is consistent with that expected for a continental margin. The trough is about two-thirds compensated and overlies a somewhat thinner crust.

6. The amount of ice lost at the ice front is not balanced by accumula- tion over the shelf area. A large amount of the high ice of East Antarctica is probably drained by the eastern portion of the shelf, entering via the Recovery and Slessor glaciers and through the apparent break in the Antarctic horst between the Dufek massif and the Horlick mountains. 20

ACKNOWLEDGMENTS

I gratefully acknowledge the assistance given through helpful crit- icism and discussion by C. R. Bentley and G. P. Woollard. Edward Thiel, co-leader of the traverse, supervised the field work and the preliminary data reduction. Hugo A. C. Neuberg, co-leader, Nolan B. Aughenbaugh, and Paul T. Walker, the remaining members of the traverse party, are thanked for their help. Air Development Squadron 6, U. S. Navy, provid- ed capable air support without which the field program would not have been possible. The data processing and interpretation were supported by a grant from the National Wisconsin. Science Foundation to the University of

I I I 21

REFERENCES

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Aughenbaugh, N., H. Neuberg, and P. Walker, Ellsworth station glaciolog- ical and geological data 1957-58, The Ohio State University Research Foundation Rept. 825-1, part 1, 1958.

Aughenbaugh, N., Geology of the Dufek massif, Antarctica, Paper presented at IGY Antarctic Symposium, Buenos Aires, Nov. 1959.

Behrendt, J. C., Geophysical and glaciological studies in the Filchner ice shelf area of Antarctica,J.Gephys. Research, 67, 221-234, 1962.

Behrendt, J. C., and E. Thiel, Sub-glacial topography from Filchner ice shelf and Ellsworth Byrd traverses, Paper presented at IGY Symposium, Buenos Aires, Nov. 1959.

Behrendt, J. C., R. J. Wold, and F. L. Dowling, Ice surface elevation of central Marie Byrd land, J. Glaciol, in press.

Behrendt, J. C., and G. P. Woollard, An evaluation of the gravity control network in North America, Geophysics, 26 (1), 57-76, 1961.

Bentley, C. R., and N. A. Ostenso, Glacial and sub-glacial topography of West Antarctica, J. Glaciol., 3 (29), 882-911, 1961.

Crary, A., Glaciological regime at Little America station, Antarctica, J. Geophys. Research, 66, 871-878, 1961a

Crary, A., Marine sediment thickness, Ross Sea area, Bull. Geol. Soc. Am., 72, 787-790, 1961b.

Evteev, S. A., Determination of the amount of moraine material carried by glaciers of the East Antarctic coast, Inform. Bull. Soviet Antarc- tic Expedition 11, 1959.

Ewing, M., and F. Press, Geophysical contrasts between continents and ocean basins, Geol. Soc. Am. Spec. Paper 62, 1955.

Filchner, W., Zum Sechsten Erdteil, Die Zweite Deutshe SuedRolar ExRedi- tion, Ullstein, Berlin, 1922.

Giovinetto, M. B., Mass accumulation in West Antarctica, IGY Bull. 50, in Trans. Am. Geophys. Union, 42 (3), 386-389, 1961.

Goodwin, R. J. Ellsworth Station glaciological observations 1958-59, Ohio State University Research Foundation Rept. 825-2, part 3, 1959.

Heiland, C. A., Geophysical Exploration, Prentice-Hall, New York, 1946.

Kotlyakov, V. N., The measurement of mass accumulation of the ice cover in Antarctica, Glaciological Research Symposium Section IX of IGY Pro- gram (Glaciology) no. 5, Academy of Sciences of the USSR, 1960. 22

Lister, H., Geophysical investigation of the commonwealth trans-Antarctic expedition, 1, The climate and ice mass balance, Geograph. J., 5 (125), parts 3-4, 1959.

Mellor, J., Ice flow in Antarctica, J. Glaciol.. 3 (25), 377-386, 1959.

Neuberg, H., E. Thiel, P. Walker, J. Behrendt, and N. Aughenbaugh, The Filchner ice shelf, Ann. Assoc. Am. Geographers, 49 (2), 110-119, 1959.

Shackleton, W. H., South, Heinemann, London, 1919.

Talwani, M., G. Sutton, and J. Worzel, A crustal section across the Puerto Rico trench, J. Geophys. Research, 64, 1545-1555, 1959. Taylor, G., Antarctic Research and Adventure, Appleton and Co., New York, 1930.

Thiel, E., and J. C. Behrendt, Seismic studies on the Filchner ice shelf traverse, Antarctica 1957-58, IGY Glaciol. Rept. Ser. 2, American Geo- graphical Society, New York, 1959a.

Thiel, E., and J. C. Behrendt, Seismic studies at the Ellsworth snow pit, IGY Glaciol. Rept. Ser. 2, American Geographical Society, New York, 1959b.

Thiel, E., and J. C. Behrendt, Gravity and magnetic measurements on the Ellsworth oversnow traverse, IGY Glaciol.Re2t. Ser. 2, American Geo- graphical Society, New York, 1959c.

Thiel, E., and N. Ostenso, The contact of the Ross ice shelf with the con- tinental ice cap-Antarctica, J. Glaciol., 3 (29), 823-832, 1961.

Tsuboi, C., Thickness of the isostatic earth's crust in various parts of USA, Geophys. Notes, 3, 1-37, 1950.

Wexler, H., Heating and melting of floating ice shelves, J. Glaciol., 3 (27), 626-645, 1960. 1 Woollard, G. P., Crustal structure from gravity and seismic measurements, J. Geophys. Research, 64, 1521-1544, 1959.

I I I 23

APPENDIX I

Data Summary TABLE I

Gravity Seismic Date Latitude Longitude Sun Magnetic Station Station Shots Declination 1 Ellsworth 28 Oct 57 770 42,.6' S 410 08' w Many 8.40 E 2 770 47.2' S 400 53' w 3 770 51.0' S 400 42' w 4 770 54.3' S 400 31' w 5 770 57.9' S 400 20' w 6 780 01.6' S 400 09' w 7 2 30 Oct 57 780 05.2' S 390 58' w 8 780 10.8' S 390 51' w 9 780 14.0' S 390 41' w 10 780 16.8' S 390 32' w 11 780 20.6' S 390 20' w S 390 12 3 2 Nov 57 780 26.8' 13' w 2 8.0 E 13 780 21.6' S 380 56' w 14 780 26.9' S 380 48' w 15 780 30.2' S 380 31' w 16 780 33.1' 380 15' w 370 17 4 5 Nov 57 780 33.9' 58' w 2 7.60 E 18 780 33.0' 360 51' w 19 780 37.9' 360 51' w 20 780 41.9' 360 51' w 370 21 780 44.7' S 12' w 22 780 47.4' S 370 34' w 23 780 50.2' S 370 55' w 24 5 7 Nov 57 .780 53.0' S 380 16' w 25 780 56.6' S 380 00' w

Sm m -m m m mm - m I m - - -= m m -mmm- I m

Gravity Seismic Date Latitude Longitude Sun Station Station Magnetic Shots Declination

26 790 00.1' S 380 49' w 27 790 03.4' S 390 04' w 28 790 S 06.9' 390 20' w 29 790 S 10.4' 390 36' w 30 790 S 13.9' 390 52' w 31 790 S 17.5' 400 08' w 32 790 S 12 Nov 57 21.2' 400 25' w 33 790 S 23.4' 400 43' w 34 790 S 24.5' 410 08 ' w 35 790 S 25.7' 410 32' w 36 S tLn 790 26.7' 410 56' w 37 790 27.8' S 420 20' w 38 790 29.2' S 420 45' w 39 790 29.3' S 25 Nov 57 420 52' w 40 790 29.6' S 11.50 E 420 59' w 41 790 26.4' S 430 12' w 42 790 23.2' S 430 26' w 43 790 22.2' S 430 33' w 44 790 24.8' S 430 58' w 45 790 127,7 S 29 Nov 57 440 26' w 46 790 29.4' 440 29' w 47 790 31.0' 440 31' 48 790 34,4' w 440 37' w 49 790 37.8' 440 43' 50 790 41.3' w 440 49' w Gravity Seismic Date Latitude Longitude Sun Magnetic Station Station Shots Declination

51 790 45.0' S 440 55' W 52 790 48.6' S 440 01' W 790 52.0' S 450 06' W 53 1 Dec 57 3 12.70 E 54 790 56.4' S 450 16' W 55 800 00.9' S 450 29' W

56 800 05.3' S 450 40' W 57 800 09.5' S 450 50' W 58 800 13.8' S 460 01' W 59 800 18.0' S 460 12' W 60 800 22.6' S 460 24' W

61 800 26.9' S 460 34' W 62 800 31.2' S 460 45' W 63 10 2 Dec 57 800 35.4' S 460 56' W a'r\) 64 800 36.4' S 460 59' W 65 800 37.2' S 470 02' w

66 800 38.0' S 470 04' W 67 800 38.9' S 470 07' W 68 11 3 Dec 57 800 39.7' S 470 09' W 69 800 40.5' S 470 12' W 70 800 42.2' S 470 17' W

71 800 43.8' S 470 22' W 72 800 48.0' S 470 35' W 73 800 52.1' S 470 48' W 74 12 5 Dec 57 800 55.6' S 470 59' W 75 800 59s7' S 480 15' W

- - - -m m - -mm m - I m m - mm- m mm -mm- I m

Gravity Seismic Date Latitude Longitude Sun Magnetic Station Station Shots Declination

76 810 03.6' S 480 31' W 77 810 07.6' S 480 473 W 78 810 11.5' S 490 02' W 79 810 15.5' S 490 18' W 80 810 19.3' S 49* 34' W

81 810 23.6' S 490 34' W 82 13 6 Dec 57 810 27.5' S 490 50' W 83 810 31.7' S 490 391 W 84 810 35,9' S 500 09' W 85 810 40.1' S 500 18' W

86 810 44o3' S 500 27' W ft4 87 810 48.5' S 500 37' W 88 810 52.8' S 500 47' W 89 810 57.1' S 500 56' W 90 820 01.3' S 510 06' W

91 820 05.7' S 510 15' W 92 14 8 Dec 57 820 10.0' S 510 25' W 93 17.70 E 820 14.5' S 510 37' W 94 820 19.3' S 510 51' W 95 820 21.6' S 510 57' W

96 820 24.1' S 520 04' W 97 820 26.4' S 520 10' W 98 15 10 Dec 57 820 28.9' S 520 17' W 99 820 31.0' S 520 22' W 100 820 33.1' S 520 28' W Gravity Seismic Date Latitude Longitude Sun Magnetic Station Station Shots Declination

101 820 34.2' 520 32' w 102 820 25.0' 520 36' w 103 820 21.2' 520 54' w 104 820 17.5' 530 12' w 5.30 105 820 13.8' 30' w

106 820 09.9' 530 48' w 107 820 06.1' 540 07' w 108 820 02.3' 540 25' w 540 109 16 10 Dec 57 81* 58.5' 45' w 22.00 E 110 810 55.0' 550 02' w 81 ° 51.4' 111 S 550 22' w 112 81* 47.9' S 550 41' w 00 113 810 44.3' S 560 01' w 114 810 40.8' S 56* 20' w 115 810 37.1' S 560 40' w

116 810 33.6' S 56* 59' w 117 S 570 17 18 Dec 57 810 30.0' 19' w 24.20 E 118 810 26.6' S 570 38' W 119 810 23.0' S 570 57' W 120 810 19.5' S 580 16' W 81 ° 121 16.1' 580 35? w 122 810 12.6' 580 54' w 123 810 09.1' 590 13' w 124 81 ° 05.4' 590 33' 590 w 125 18 19 Dec 57 81* 02.1' 51' w

-m-I- - m -m -=mI I m - -m-m m m-m m - - I m

Gravity Seismic Date Latitude Longitude Sun Magnetic Station Station Shots Declination

126 800 58.6' S 600 09' w 127 800 58.0' S 600 38' w 128 800 56.9' S 60* 58' w S 129 800 55.4' 610 08' w 130 800 53.9' S 61 18' w

131 800 50.6' 610 38' w 132 800 47.5' 610 38' w 133 19 21 Dec 57 800 44.3' 62" 19' w 134 800 40.1' 620 30' w 135 80* 36.4' 620 40' w 136 800 32.0' S 620 52' w 137 800 28.9' S 630 00' w r%0 138 80* 28.1' S 630 02' w 139 800 27.4' S 630 04' w 140 800 24.1' S 630 12' w S 141 800 19.9' 630 23' w S 142 800 15.8' 630 34' w S 143 20 22 Dec 57 80* 11.7' 630 45' w 26.90 E S 144 800 07.2' 630 56' w S 145 800 03.0' 640 02' w 790 146 58.7' S 640 17' w 790 S 147 21 23 Dec 57 54.3' 640- 27' w 148 790 S 790 50.3' 640 38' w 149 S 790 46.0' 640 48' w 150 41.7' S 640 38' w Gravity Seismic Date Latitude Longitude Sun Magnetic Station Station Shots Declination

151 79* 37*4' S 650 09' W 152 79* 33.1' S 650 20' W 28.8' S 153 22 26 Dec 57 790 650 30' W 790 30.0' S 154 650 00' W 155 790 26.' S 650 12' W

790 22.1' S 156 650 25' W 790 18.2' S 157 650 37' W 790 14.4' S 158 65* 49' W 790 11.5' S 159 660 01' W 06.3' S 160 790 66* 14' W

790 02.6' S 161 660 26' W 23 162 30 Dec 57 78* 58.7' S 660 38' W 163 780 54.0' S 66' 52' W 0 164 780 49.5' S 670 05' W 165 780 44.7 S 670 18' W 166 780 44.7' S 670 31' W 167 780 47.6' S 670 33' W 168 780 52.4' S 670 47' W 169 78* 54.8' S 680 01' W 170 780 53,3' S 680 10' W

171 780 52.1' S 680 19' W 172 780 50.6' S 680 26' W 173 24 2 Jan 58 780 49.2' s 680 37' W 29.50 E 174 780 44.9' S 680 43' W 175 780 43.5' S 680 45' W

- - -m-m-m- - I-- I = m -m- mm m - m me- I m

Gravity Seismic Date Latitude Longitude Sun Magnetic Station Station Shots Dec lination

176 780 41.2' S 680 49' W 177 78* 38.1' S 680 51' W 178 78* 37.5' S 68* 54' W 179 780 37*7' S 680 36' W 180 780 36.3' S 68* 12' W

181 780 42.6' S 68* 10' W 182 78* 45.3' S 680 09' W 183 78* 48.5' S 680 16' W 184 80* 12.4' S 630 19' W 185 800 13.1' S 620 53' W

186 80* 13.8' S 620 26' W 187 25 7 Jan 58 80* 14.5' S 620 01' W tAU.) 188 800 15.2' S 610 34' W 189 80* 16.1' S 61 01' W 190 80* 16.5' S 600 47' W 191 26 8 Jan 58 800 17.0' S 600 28' W 3 24.00 E 192 800 15.6' S 600 09' W 193 800 14.9' S 590 57' W 194 80* 18.8' S 600 04' W 195 800 24.1' S 600 08' W

196 800 29.0' S 600 14' W 197 800 34.2' S 600 19' W 198 800 39.2' S 600 20' W 199 11 Jan 58 800 44.3' S 600 30' W 23.8* E 200 800 48.3' S 600 34' W Gravity Seismic Date Latitude Longitude Sun Magnetic Station Station Shots Declination

201 800 52.6' S 60* 37' w 202 80* 56.9' S 60* 39' w 203 80* 57.3' S- 600 48' w 204 800 57.9' S 59, 37' w 205 800 56.0' S 590 14' w

206 80* 54.4' S 58' 54' w 207 13 Jan 58 80° 52.2' S 580 46' w 23.96 E 208 800 47.7' S 580 30' w 209 80* 43.0' S 58* 21' w 210 27 15 Jan 58 80* 38.2' S 58' 17' w 23.2* E

211 80* 34.3' S 580 19' w 212 80' 30.4' S 58* 21' w 213 80* 27.3' S 58* 13' w 214 80* 23.2' S 580 07' w 215 80° 26.0' S 57. 56' W w 216 80* 24.4' S 570 40' W 217 80* 21.4' S 570 18' w 218 80* 18.3' S 56* 57' W 219 80* 15.4' S 56* 32' w 220 80* 12.8' S 56* 07' W 550 221 800 10.4' 43' w 80* 07.7' 550 29' 222 54* w 223 80* 05.1' 56' w 224 Replaced 17 Jan 58 80* 02.6' 54' 32' 20.7' E by plane

m m - - - - - m m- I-- I m n -m m m T - - m m -

TABLE II

Gravity Surface Ice Rock Observed Free Air Station Elevation Thickness Surface Gravity Anomaly meters meters Elevation gals mgls meters

1 42 231 - 792* 982.9246 -48.4 2 49 289 - 858 982.9266 -47.1 3 49 289 - 890 982.9329 -43.2 4 59 378 - 894 982.9378 -37.3 5 64 422 - 923 982.9425 -33.2

6 71 486 - 968* 982.9455 -30.3 7 69 466 -1040 982.9497 -29.0 8 71 486 -1056 982.9583 -23.2 9 75 523 -1070 982.9649 -17.3 10 69 466 -1103 982.9731 -12.6

11 72 495 -1142 982.9785 - 8.5 12 72 495 -1195* 982.9854 - 5.3 13 74 515 -1225 982.9759 -11.1 14 79 560 -1096 982.9834 - 5.2 15 75 523 -1018 982.9887 -3.1

16 79 560 -1018 982.9856 -6.7 17 80 568 -1045* 982.9802 -12.3 18 74 515 -1098 982.9789 -15.4 19 72 495 -1317 982.9666 -30.7 20 79 560 -1365 982.9639 -33.3

21 82 587 -1267 982.9727 -25.4 22 82 587 -1164 982.9827 -17.0 23 80 568 -1081 982.9918 -10.1 24 73 505 -1041* 982.9992 - 6.5 25 83 597 -1055 982.9966 -8.0

* Seismic Reflection Gravity Surface Ice Rock Observed Free Air Station Elevation Thickness Surface Gravity Anomaly meters meters Elevation gals mgls meters 26 78 550 -1076 982.9982 -10.0 27 87 634 -1099 982.9952 -12.1 28 88 643 -1123 982.9946 -14.3 29 88 643 -1133 982.9954 -15.5 30 82 587 -1153 982.9973 -17.4

31 82 587 -1167 982.9978 -18.9 32 86 625 -1271* 982.9975 -20.0 33 88 643 -1236 982.9959 -22.2 34 80 568 -1247 982.9933 -27.8 35 81 578 -1185 982.9934 -28.1

36 80 568 -1097 982.9959 -26.4 37 81 578 - 967 983.0010 -21.6 38 77 550 - 722 983.0163 - 8.3 (/3 39 74 515 - 566 983.0240 - 1.6 40 58 367 - 309

41 68 468 42 82 587 43 185 347 - 162 983.0171 29.6 44 451 532 - 81 982.9484 41.6 45 599 676 - 77* 982.9056 42.9 46 650 721 - 71 982.8923 44.4 47 695 851 - 156 982.8740 39.1 48 749 787 - 38 982.8693 49.3 49 740 868 - 128 982.8659 41.3 50 729 890 - 161 982.8677 37.8

- - - - m - - m - - - I m m - - - m - - I m

Gravity Surface Ice Rock Observed Free Air Station Elevation Thickness Surface Gravity Anomaly meters meters Elevation gals mgls meters 51 715 883 - 168 982.8720 35.8 52 702 831 - 129 982.8795 37.4 53 694 853 - 159* 982.8805 34.2 54 681 936 - 255 982.8798 27.1 55 660 972 - 312 982.8842 22.7

56 641 962 - 321 982.8916 22.0 57 609 933 - 324 982.9029 21.3 58 570 882 - 312 982.9176 21.8 59 539 877 - 338 982.9294 21.9 60 468 836 - 368 982.9526 20.9

61 370 712 wA - 342 982.9774 13.3 Ul 62 273 606 - 413 983.0011 5.0 63 153 658 - 505 983.0289 - 6.3 64 89 627 - 671 983.0324 -23.1 65 74 515 - 859 983.0241 -36.4 66 77 540 - 929 983.0190 -41.0 67 79 560 970 983.0164 -43.4 68 81 578 - 998* 983.0146 -44.9 69 84 606 -1055 983.0130 -46.0 70 87 634 -1119 983.0112 -47.7 71 92 680 -1192 983.0081 -50.0 72 95 657 -1264 983.0070 -52.2 73 98 686 -1413 983.0000 -60 .2 74 96 668 -1270* 983.0159 -46.6 75 100 754 -1241 983.0199 -43.3 Gravi ty Surface Ice Rock Observed Free Air Station Elevation Thickness Surface Gravity Anomaly meters meters Elevation gals mgls meters

76 108 837 -1212 983.0225 111 -40.0 77 863 -1218 983.0243 -39.2 78 107 820 -1268 983.0248 -41.7 79 105 800 -1288 983.0269 -42.0 80 96 718 -1312 983.0308 -42.6

81 89 652 -1306 983.0365 -41.0 82 90 662 -1307* 983.0388 -40.1 83 89 652 -1292 983.0379 -43.2 84 91 672 -1287 983.0353 -47.0 85 93 689 -1276 983.0331 -50.4 0o 86 92 680 -1228 983.0346 -51.1 87 89 652 -1147 983.0391 -49.3 88 85 621 - 962 983.0515 -39.9 89 80 568 - 714 983.0690 -25.8 90 139 314 - 175 983.0608 -17.5 91 215 344 - 129 983.0510 -5.7 92 275 397 - 122 983.0381 - 1.9 93 323 375 - 52 983.0339 6.9 94 363 517 - 154 983.0148 - 1.8 95 390 590 - 200 983.0038 - 5.3 96 427 630 - 203 982.9945 - 4.2 97 473 589 - 116 982.9916 6.2 98 523 404 119*4 982.9881 99 17.1 581 270 311 982.9891 35.2 100 640 255 385 982.9783 41.8

- - -m m m -- - -I -R -R I m - - - -i - i m- m - - I-=-

Gravi ty Surface Ice Rock Observed Free Air Station Elevation Thickness Surface Gravity Anomaly meters meters Elevation gals mgls meters

101 661 0 661 982.9922 61.7 102 394 459 - 65 983.0197 10.4 103 263 397 - 134 983.0604 12.2 104 190 440 - 250 983.0812 12.0 105 124 709 - 525 983.0888 0.7

106 105 800 - 754 983.0844 -8.0 ' 107 112 872 -1252 983.0558 -32.9 108 121 949 -1493 983.0454 -38.9 109 129 1036 -1681* 983.0395 -40.8 110 137 1105 -1681 983.0342 -42.1

i1 146 1195 -1708 983.0290 -43.0 112 147 1205 -1761 983.0232 -47.0 113 151 1244 -1793 983.0180 -49.5 114 153 1262 -1762 983.0180 -47.3 115 149 1225 -1697 983.0224 -42.6

116 154 1275 -1604 983.0260 -35.9 117 158 1312 -1542* 983.0277 -31.4 118 159 1320 -1450 983.0306 -26.6 119 151 1244 -1382 983.0345 -23.6 120 151 1244 -1442 983.0265 -30.0

121 149 1225 -1423 983.0250 -30.6 122 145 1184 -1392 983.0250 -30.3 123 141 1147 -1304 983.0291 -25.8 124 137 1105 -1168 983.0366 -17.8 125 131 1046 -1133* 983.0376 -17.1 Gravi ty Surface Ice Rock Observed Free Air Station Elevation Thickness Surface Gravity Anomaly meters meters Elevation gals mgls meters

126 127 1006 -1068 983.0400 -14.3 127 112 865 - 753 983.0423 -16.4 128 144 876 - 732 983.0374 -10.9 129 177 829 - 652 983.0335 - 3.9 130 196 810 - 614 983.0296 - 1.2 131 200 132 794 - 594 983.0277 - 0.3 227 817 590 983.0183 0.1 133 224 850 - 626* 983.0142 - 3.4 134 210 842 - 632 983.0154 - 4.5 135 197 784 - 587 983.0206 - 1.5

136 168 701 - 533 983.0302 1.3 00 137 103 597 - 494 983.0487 1.2 138 77 542 - 465 983.0550 - 0.1 139 76 533 - 520 983.0561 1.0 140 78 550 - 570 983.0591 6.3

141 78 550 - 590 983.0609 10.2 142 81 578 - 580 983.0604 12.7 143 78 550 - 575 983.0590 12.4 144 75 523 - 565 983.0586 13.4 145 78 550 - 580 983.0539 11.7 146 82 587 - 580 983.0487 10.0 147 82 587 - 624* 983.0460 9.6 148 79 560 - 600 983.0442 9.0 149 77 542 - 602 983.0401 6.5 150 77 542 - 583 983.0368 5.5

m m m - -_ - mn - - - L - I m - m - - m m - m - - I m

Gravity Surface Ice Rock Observed Free Air Station Elevation Thickness Surface Gravity Anomaly meters meters Elevation gals mgls meters

151 77 542 - 576 983.0327 3.7 152 77 542 - 571 983.0284 1.7 153 77 542 - 582* 983.0231 - 1.3 154 75 523 - 503 983.0282 2.5 155 73 505 - 541 983.0219 - 2.3

156 74 515 - 582 983.0143 - 7.4 157 79 560 - 613 983.0063 -11.7 158 77 542 - 625 983.0019 -14.6 159 69 466 - 644 982.9993 -18.1 160 66 440 - 621 982.9971 -18.4

161 63 413 - 588 982.9962 -18.0 162 64 422 - 547* 982.9947 -17.0 163 68 460 - 517 982.9928 -15.0 164 62 405 - 525 982.9920 -15.1 165 58 368 - 495 982.9928 -12.7 166 54 333 - 439 982.9983 -8.5 167 60 387 - 477 982.9955 -11.1 168 66 440 - 468 982.9972 -10.3 169 82 482 - 400 982.9988 -5.1 170 98 418 - 320 982.9990 0.9

171 214 421 - 207 982.9791 17.4 172 334 510 - 176 982.9481 24.3 173 400 572 - 172* 982.9299 27.3 174 392 507 - 115 982.9338 31.2 175 350 468 - 118 982.9441 29.4 Gravity Surface Ice Rock Observed Free Air Station Elevation Thickness Surface Gravity Anomaly meters Elevation gals mgls Meters

176 261 415 - 154 982.9642 23.3 177 137 313 - 176 982.9938 16.5 178 86 563 - 477 982.9824 -12.3 179 241 425 - 184 982.9654 20.4 180 223 403 - 180 982.9697 20.0

181 347 592 245 982.9350 19.9 182 258 630 372 982.9587 14.5 183 238 600 362 982.9666 14.4 184 74 515 500 983.0528 4.6 185 66 441 460 983.0453 - 5.7

-is 186 57 359 441 983.0397 -14.4 0 187 57 359 378 983.0364 -18.1 188 54 333 280 983.0369 -18.9 189 i1 471 360 983.0246 -14.0 190 146 596 450 983.0163 -11.7

191 162 764 602* 983.0152 8.1 192 100 664 564 983.0353 6.5 193 60 591 531 983.0482 5.6 194 81 651 570 983.0421' 7.1 195 79 693 614 983.0436 8.9

196 89 694 605 983.0450 6.8 197 98 745 647 983.0464 5.2 198 101 778 677 983.0472 5.9 199 106 783 677 983.0497 4.3 200 129 800 671 983.0471 1.8

. - m ------m- m--w 91 . m

Gravity Surface Ice Rock Observed Free Air Station Elevation Thickness Surface Gravity Anoma ly meters meters Elevation ga is mgls meters 201 133 876 743 983.0441 -5.6 200 136 952 - 816 983.0413 - 9.5 203 157 1022 865 983.0323 -12.2 204 107 818 -1002 983.0344 -25.3 205 112 872 -1021 983.0314 -26.4

206 112 872 -1048 983.0291 -27.7 207 107 813 -1091 983.0274 -30. 1 208 106 809 -1120 983.0242 -31.5 209 110 847 -1085 983.0240 -28.2 210 105 800 -1065* 983.0257 -25.7

211 100 755 - 931 983.0271 -24.0 212 97 752 - 898 983.0290 -21.1 213 92 670 - 907 983.0285 -21.6 214 85 621 - 911 983.0288 -21.4 215 88 643 - 914 983.0294 -21.3

216 100 755 - 887 983.0273 -18.9 217 96 668 - 957 983.0222 -23.7 218 89 652 -1050 983.0166 -29.9 219 86 625 -1098 983.0129 -33.1 220 84 607 -1120 983.0111 -34.2

221 81 578 -1155 983.0086 222 -36.4 79 560 -1163 983.0076 -36.7 223 74 515 -1172 983.0075 -37.0 224 73 506 -1143 983.0091 -34.4 42

APPENDIX II

Seismic Reflection Records ------m m m -m m------m-m m -mmI -

......

Station 1 Ellsworth Shot Location: 20 m from #1 Record: 1-7 Spread: In line Date: 16 Oct., 1957 Geophones: odd numbers vertical; even numbers horizontal transverse Shot Depth: 8 m Sensitivit,;: #1-#12, 7; #13-#24, 8 (sensitivity range in 10 db steps) Charge: 200 g TNT Filters: High cut KK215, Low cut KK30 RI = first reflection from bedrock 4I '. ..." ."." ., .' ." ,.i"0,- . , . " .. .. ' ., .+' ;' b '" .:. ------N"O%,' -,%0. ' ," , ;- . ' , ,q : '., IVI . /~MA V .M~w ~ ~ . Sw ....MY . . . . - . + -% %A% * - f - - ' W+ ~~~~~~~~~~~~1." '" " " "'",.,,,. ,.i .. t T- , " i : . . , - ". ' " ;.. " "' ' : ' " ' .. VIqqoiIqq-- -- +- =_ .. . . Of.. ,' . . . . ,' , ''',: - . f...... --VFI tov Win%- q 4 % bI FJ lblbI +lb6+b4 bb : .i ,.+ q v'Vtiv,.v'f w - 0 - - % - 1 % . ! . . :2 ;.. . .,,, 4t...... r 1 ' '-- '..,'-,..k -...4.',--" lbpw6 ra 1% -; ...... , .. . . .ow', :, ". ' ,, +.,, , •.0-1W i4- %%P4ilbl V '+40-0 w - -I-"- % 4 - %- 6 % 'i 1 WOO w-- vi a - 0 , 6 1 %- , -%- 06zN-, Rpm_- i ... - ""'. F------4 4 t lbM 4pw.." -1V *.,- -I.' I ,I • _.PP • , A- t

, W'opo ,"11", - - .----- 4-~Lw. jA~' 4' b. Izz1uiizuI~~ -~ - • . ..- ...... - ,?....ko

..,-.. , -.-.-.-.--.- .-.ONoftt , " , t %Ov,vv v%4.4w%p -m a, 4 4-4M4 -. ww A'- Ml- I- - -- 0. --400%^%%4 v Aoj0 -1% %im 04 t - & % ow% 4 - % m& L ...... J...... J.__ "...... I - - - - I v I,WV WV..... vv .v ,, , , %%-%-lb------,' !,iI,} - 1l.. t...,....+.....,..,. __:. _,_...._- _ ... :7 .:,/1- .!.2.TI ..!.h ._.. ow.,..._,.._.. . -

%AV4 V,* 1%0 %" 4 Niblb A -%0-"

i 4

Station 2 Shot Location: 300 m from #13, in line with #1-#12 Record: 2-7 Spread: L with #13 at apex, #12 20 m from apex Date: 29 Oct., 1957 Geophones: Alternately vertical and horizontal transverse to Shot Depth: 8 m shot azimuth, most remote vertical Charge: 200 g TNT Sensitivity: 8 Filters: HC, K215

- -mm mmiI ------m - m - m I ------m m m ------I I =

-I Ir Ir "f f I-IFlL I II II

I v 7 IIli U,

[M1 i l Lki go If r 11

Station 3 Shot Location: 300 m from #13, in line with #13-#24 Record: 3-4 Spread: L with #13 at apex, #12 20 m from apex Date: 1 Nov., 1957 Geophones: Alternately vertical and horizontal trans- Shot Depth: 8 m verse to shot aximuth, most remote vertical Charge: 200 g TNT Sensitivity: 8 Filters: HC K215 its., , .I', ki4,., A +iL,6 i,~1!4,rik .....,i'+....'i,. Ovo 4.-pAimI - - 06k op- 0 tjowt _ _ .Ii .- 'Im I Vil 'III, k' ..L,,.,i,.,.,, 1,. f ! 0. %*V .W.- ^44VAN. -W-V"W",W.F....- Jr%:. PIVOW -dkA. - 4 A- '*I&-+.r_- -A--- - I IAAAVI%L.VAOU'k%mr 1 j v ; % . - 4~uL . -. Pm %440. LZ604. ti ':i L[I:, ~ ,o .il. I .4' it ~i .4",, -'**'.." .: ." "I - - .. -. . III, _ bl g .*vi I- 1.1,1,, i ] I#1 ml ' l r '| I IF n lM I .1 lr, m 1 %1J"l.lk •,ima r vwltl',K" IIT r.. 1I 0p AID, tJ..' A''1k, __,_ + 4 _,__. . #I-F ir

I ',T -h1IA lt 'WWjI VA( ffl ,le 1, mI .,I I I,,,, foio 'I -YAA W~oo~6swr% ----I - U' . ... 0.W -. I, ! ',- I t ' 0' - w.**.*Nb WAMOVO. 1,11 4 r IA U "'A. " -I,,'I'' ~ Jit " ,'.Ai,,'' " MW WAAAMW. ,_~ ~ ~_ ]_*Okg I-*4w14po*.p-*-1po*,&L T" II PN~VA ~AJ ~ JL~ AAU. ~ ~AAAJ#~I r . 2•.,I , 1 . II --i-- ! I, -- +-, " - , -1,! " , , o- - t ! ! iA~ ,t I ~~*-'~' 1'--~ ~ - - ±-~ ~ I.~4 ~EMWI,SYM~ ~.Ku ~ &~~'.v~s-4 .'~"~"iAw ~. -. -~i~- ~~4 I - L - l,o,t,i,lll,- i...I .., . '4'. I - - -. I - "I -

'I I 2_ ,, I!..i I ~-~~&---~-- -

Station 4 Shot Location: 300 m from #13, in line. with #13-#24 Record: 4-3 Spread: L with 13 at apex, #12 30 m from apex Date: 3 Nov., 1957 Geophones: Alternately vertical and horizontal transverse to shot azimuth, Shot Depth: 8 m most remote vertical Charge: 200 g TNT Sensitivity: 9 Filters: HC, K215

------m - m - --- m- I m= - = ------= -m-- m I m

_ Ll,1I i-- - i~f~; r U111911111•II I lMUlL,[li IdllT k .M ...... ,I r;!, ill 1, TITTifiw 'F'i! I'i ' 91',l ,.'

I Ii" ', IM'I I' 1 dI "i " '81lt.,, 171 .v

Va s i, .1O v11. '-4! IIi II ii I II11Ull '1 II!!111' ,_u-J,F;;~ ,; EU I Fl ;I :![l ! I IIIII I. m I I j ][[.A-Aal [.Jr- :~~~ ii;! T~!F F I T T . I I • ,i ,! ,! 1 , Ill!j T-1TT£I 71 -. . ._ITifI -111- 1111 i Jil ___f ___1 . " i l l rT- 'IVP 1I1 il' -J A"A-L-j -7-r-l T-r-r7 Ii, -1 T I IFF TT-I JT Ii;"" ILA, -,A- LI -. "- - ... I I I,i'II.f I i ImI uI .,ii M ; opt! - , - 4- 1 .1f ~ -fri F ,{vY~tTht1tt~ ~-~4I4 ~ -A l__T T7 7T7_ O -00 0 0 LOOW0 0, " ., -T,T 'i --rr-r..rr. . n

Station 5 Shot Location: 300 m from #13, in line with #13-#24 Record: 5-3 Spread: L with 13 at apex, #12 30 m from apex Date: 6 Nov., 1957 Geophones: Alternately vertical and horizontal transverse to shot aximuth, most remote vertical Shot Depth: 8 m Sensitivity: 8 Charge: 200 g TNT Filters: HC K215 4

SAW.1 & JU Urwl(u2u,kwlrmwl, ;I6 I ___ 1 Tr~r~r~ P 1L#XF-I~I t.'| if, . -t MLF'd || L'IIlr.! 1 %-1IA wylom _ T ? 4L1.. . - 4-- +-i ,- + ~ F~- '1 A ,, ,t ov. ~ 4 ~ I I I IbK~Wvt I1 vf~tI ACI :'LI t ti V S I I,I1II- LI.! F-Id il Iril m, I T' ' I "T ".. .. ' rfb ILI-,- Y. F.ji1 iP IFl--TlI 1 wIn,- Ii-IT Ll I J L ___ A. .1. * .L~~' L L .~LL LI63 Will El I') TITl 17 I'-r _I1;z L [I2 F I &w,IFal I t i I- rT'T Mll,'l IIII, [IJT[J. Z .. ..,. -! -Ilvyy ;lIf C') ~II .lIll TI Tu 1, .-I&LIJL"Ll A LLLIL Li J-JJ-l I I t.ii T77-I : II,lN IJ-I-. ,III III III I I I ~ B~LLIJ{rptif ~LbJ~ti IAIILU 4~ I , .Ol , Fl' R.EF I Jf T111 FFTTTIM Iii . LIT t ' I , ,;i 'Fr'I,o li L1.2 - 11.111 .i:' (I! ;!i, . " " : ', ... . .lt -...... , -i , IRA&lI ,III,,,, I- AlmI!! . .. Ir1-d r rI -1 F - I [ l . .. rt t i' t t , . . II I I 11 11 7ii i ;:1 , ilik l il I II A'tV3 ,i_l

Lij ,I -.11 1 1i1 i i ,i; ~LJiL .. I.-, Station 6 Shot Location: 300 m from 13, in line with #13-#24 Record: 6-3 Spread: L with #13 at apex, #12 30 m from apex Date: 9 Nov., 1957 Geophones: Alternately vertical and horizontal transverse to shot azimuth, Shot Depth: 8 m most remote vertical Charge: 1.4 kg petrogel Sensitivity: 6 Filters: HC K215

m - -- m - m m - m - I = - - - m- mm m - - I nm

III kh,I,',,iAIk -. l ,tll i -T-- ,1 i-1 - 1161l .71j, I ' T-111 I , . ... 1,3RVI/l | , i I I I I I I I I JE.I l I.T:I . T ,! ]/ , TT -T,-77-7 r :IT T I 7 TT 1.

II!, A, ' I i : " [ : ' : j r : " : : ' " 1 'J-J ...... ] ' li J:l " ill ] l " l . ... -. J JJJ oilJJJj. J.jjj- j j " ?V t , l i r t l tI T.lT I t ;l-tt

[ill]tlIlllI iiii 'I '' " li ' ] 71T 111T 1-1 11 l Villl ' ,, I I r -r-- T T-Ir T j"" , '"' i ;;; ;; ;... ;lW l;i i i

'I TT I] --- _- _+. ,l I Ii l 1 I'{'i ll - T I 'fIiji( [I I iii I 1 1 ! ,II LIP ~~~~~~d~~~~~- +v+MJ # I II bU I",IiI T4 l4lJ, I.- ,11LU III_ W~ woo. ..,,. v.hill '?WWIIi-I 71 -1IT I ITTI 7 J Ao I I f-i 111M L - .1 1 i.: I rITNUTIP"W IRTF1r.1LlN.O. I I TT T iI~

Iill~ 1'!l>11 'Iiri~ J~H~l~Hi JlLh 1-1i 1 Station 8 Shot Location: At apex Record: 8-2 Spread: L, #12 and #13 15 m from apex Date: 29 Nov., 1957 Geophones: Vertical Shot Depth: 8 m Sensitivity: #1-#7 and #18-#24, 8; #8, #9, #16, #17, 7; #10-#15, 6 Charge: 200 g TNT Filters: LC KK30, HO KK215 4I

C

Station 9 Shot Location: 15 m from #1 Record: 9-2 Spread: In line Date: 1 Dec., 1957 Geophones: Vertical Shot Depth: 8 m Sensitivity: 9 Charge: 200 g TNT Filters: LC KK30, HC KK215

- -- m-mm -- =m= m m-- -5 Im - - mm -mm-=- m--I I -

I I I I I , i I I I 1 I I I I *JVA\ V. I VJWdVA~1 ~~4AIv ~~ 4 ~ ~I I JI II- -.. . t~Wh1~~"L4".t V V%I'P~ 1 ~ I ~ %Av 4-... ., pw -4'---- . 1%* *1 ,i 0# Al Ik T ~ ~1 -K if I ~' I ('JV"~ {-~--p.- + - - L.....UJ.....± - .. . a, 0:A , Pvv~iU 'tLi~ 1w : -. , . • . . ... _l . : . . z ,.a , . n , , , ~vv~v~ .~v Ln Z'N~:4 "I11,,t r*l MPVvr, VA.,A _-Z-_i/iL- __7~ ~7 I[IIi,- I]TrI 4.- ~tmW

,,,Sli' v-A r,, I' " ur.. - -rrl- v W Ir .wI~LA...J.L .. 7" JIMI1JA Ili NL11' Lw. I LJ-L2 I i I . . I I I I - . l IlI l iLL. 4.L~-~ .ini I h~

Station 11 Shot Location: 300 m from #13, in line with #1-#12 Record: 11-3 Spread: L with #13 at apex, #12 30 m from apex Date: 3 Dec., 1957 Geophones: Vertical Shot Depth: 8 m Sensitivity: 8 Charge: 200 g TNT Filters: HC K215 4I

Station 12 Shot Location: 300 m from #12, in line with #1-#12 Record: 12-4 Spread: L with #1.2 at apex, #13 30 m from apex Date: 5 Dec., 1957 Geophones: Vertical Shot Depth: 8 m Sensitivity: 8 Charge: 200 g TNT Filters: LC KK30, HC KK215

mmmm- -- -m m - mmm I = i m - - m - - -= -- - I n=m

$+

I L .1 I I I I ! I

_ _-Ok_AP _ _ _ _ .,,*,*.l%v*,' --- L - I I ~4 . . . .. - ';-..,r.__,,_,_.,_._ IF vw J . .NJ lv4vAv\l 4 OwJ~v

.,.....%.W_vre,l,wJ,,wlNV ,.,

j ~L r%

.. U M,\ m& Ap PAA 1 --_--- .!. it V ,---A- -

ILI1 11 1 1 1 11 IIIII1! 11[11111 pip I d00 1 W'Af~vA -No 7 'T- 4H444o o 11-- 1 -4 W614 1II1

i IiA IIld! I I I I i I A . ~LLL .. _ LL__._ i -Ii-A-ik I Li I4 1 , I - ,I j.,. .L4I4I.II I UI I . LI .I II-I,

Station 13 Shot Location: 300 m from #24 Record: 13-2 Spread: In line Date: 6 Dec., 1957 Geophones: Vertical Shot Depth: 8 m Sensitivity: 7 Charge: 200 g TNT Filters: LC KK30, HC KK215 - -4 -.. ..

,4, tI

4 ,-, i " ... .-. .~. i w. - . . , - ,f,,i ,.lp "- , ...-.....hi-= - . . .. *1 U, Pi

.. - I I I I 1 ,0. . I h LillIL Station 15 Shot Location: At apex Record: 15-3 Spread: L with #12 and #13 Date: 9 Dec., 1957 15 m from apex Shot Depth: 9 m Geophones- Vertical Charge: 200 g TNT Sensitivity: 5 Filters: LC KK30, HC KK215

m - m- -m-m-minim 0 I m -= m m m -M------I =

I , I I -I I V~I~IVV'rAP~'l ~ r-- 7iT_ii J ... __ - .. . . +. -.. . .. 7 - ./A IRA_ 0 7.-- ...... - ',..

---:-:- 1-7 _ --; 7 .-_1 Am ' - . - . ',1,q " IP' Iof i:]L_ , WAN% t '!'.,. .& . . ------l.. . "

jI f -- fiA- v -- r-I 1- - - i &- H- - I - ~ ~ L'V--4'--'--'. ~ -- *---~ 4 .---.---- 4 - 4 - 4 - L ,'i iI L[1 ": -Il i? i A~ -PU F--- U,l N'trl Ull ,A.AL, K

------oi' ol, F 7 4 ii22 i:i 2_ "i2:12 2i2 ?" ,i,Iq V,.-, Pona 0

ELLi WIM I I I I I Pw, tTvvkiALIIALkj- - -- i - A IA I I i io 1.11 airlU'Iallr -1 . . t" - r I 'I I I I TIT' L- I-L-L_ __-___ - [ L _ _l 1 -.. L ._ l A,, _. [_ W" ,' -____i -.-.: - -. _-. 7 .-117[ _ T; J I 6P4,

IAsisa I - W, Nqlv It , VI 77FII11iil I,I ll 1T11fii17 KJIIH ~ Station 16 Shot Location: 300 m from #13, in line with #l-#12 Record: 16-2 Spread: L with #12 30 m from apex Date: 16 Dec., 1957 Geophones: Vertical Shot Depth: 9 m Sensitivity: 8 Charge: 200 g TNT Filters: LC KK30, HC KK215 R R I

ThjmThi7T~i IL . . . . . V w.bT...... w. i...... m ------

4 ~~fl 4~%~ MA ~w 'I'~ - • . . ,.I .1..;'L. ,.*,SIVA,"a ~ I ,ro il;I" ";'"1 t ------

AON~-"owoqA 1 "I . ,, . ... -FAA-'m-MAR W Ip6mo-A VOI-A&P I-MAI-A-104 AIM A IAl MAM-w Ti, 7-7 777-- T7 $ , ' r~f; ~7't i-l AIR&AR-AA Mo Pim A,M- 0-1 -,-,. ,,f'., ' " i: .l. . ... ,, . , I Frri I I --- A WNW r.1 OA'. ,' Ul ~ r ,,A,i , , - ---- ,,,, - ,,...,, . M,0 -w Ii 101 ------T:.-I .TIT _ _T-_ -I &AAVA MWA

- - 164 -1- -A I, A"&%4TL --

Station 16 Shot Location: 300 m from #13, in line with #1-#12 Record: 16-3 Spread: L with #12 30 m from apex Date: 16 Dec., 1957 Geophones: Horizontal, alternately transverse and longi- Shot Depth: 9 m tudinal, #12 and #13 transverse Charge: 200 g TNT Sensitivity: 9 Filters: LC KK30, HC KK215 R = S-S reflection from base of ice shelf S

-mm m -=-m-=-M-M 0 I m m - m ------I m

,

-MOWN-mmona adoww

-"

~ ~1 *Iwo.

~~ -oo""- "-wmpa.Wi u,l

TJ-JT - - TI,

i

1401;

Liiij-.

IT FT-

Station 17 Shot Location: 300 m from #13 in line with #13-424 Record: 17-2 Spread: L with #12 30 m from apex Date: 18 Dec., 1957 Geophones: Vertical Shot Depth: 9 m Sensitivity: 8 Charge: 1.4 kg petrogel Filters: LC KK30, HC KK215 RI \A-WVO A ~Ti' ,' i %sv+f%eftd.4~bmf~r%..rnsmP%i t- NO a - I - h - M44~ -n j d~-~ ':1.,, Lh I f 1 to to I eA ~ ~ IN * IWif,wiizc~'~i~:v L~ roo o= 00880 , m.lllJ ' - " NI .-~ d~' ."-, ,jt."~ Iqw-RAIN .l....LL1A --A4- , oo. I1. - 1... L, . .-Lp....r.. --.. JL , 1mW"1!AMIMli iEiE l Ba]IllIJiEliiq il.l illllll lPm lb !' . ) • _ .|.-iI sIAJl, _'-'_l Ak Rl A~f-AAM~~U WblI 0 - i+ (-n set. IF 116' L L" A~I~i ,-v' hlll Jit MNLMInAl iJ~Y~ ONwN ro; I'A AlrMP! vo'atl I14 1!Av r "rl t

90'Ii AA V V" lv ~I Ak IAA#,0 ~iLflL~Z WrN*V h1~ jNmlNv,vwh*%rl -po - - Lru .J Lid 6j, A I -L , I)l - - - w-m-m--ma-- - ? "Im. yt 471"XI If ~~'FVLII1.V I 1 ,iliit UII~V'i I~. I ~ | 1.* jAli. Ii I I - - A , -I iii _.__..L__ LL! ± w.r g ~ ~ ~ J ~ L~J~L~LJMI 111 .W.A llti:t 1 i -- , - I= - - . I I I- I I I i I I "- - 61-11,111WE"ili 1.11,

Station 18 Shot Location: At apex Record: 18-3 Spread: L with #12 and #13 15 m from apex Date: 19 Dec., 1957 Geophones: Horizontal, alternately transverse and Shot Depth: 9 m longitudinal, #12 and #13 transverse Charge: 200 g TNT Sensitivity: 8 Filters: LC KK30, HC KK215

mm ml ;m - - - m -=I I m m -mm -M- m m -= --m-- i--

11*"' "1 *~*~ A e 4AtN - -- -oo -- *1~$ ~ ,,I I . ' N-"-NW . . si ~'i~rrrrr__ - ~ g,, , I '~~' Ilr7TT1'

i - ~;i:~* '-T_'T l 1*11 oil..-+t.[kTI IT ! 1" 1- W~ v 'Il l,r- 7-7U "4* &Ct'fI AVI,V' I i --0PAV*PWo __

U, ,t~ '1114l9444,1.11lfflirI'IT AA&Aw

ALii r ,." '04( .0 i ------I ,i~ L11",'1. ,ii+,i,l ,,,i,,i T I _T lI+ i LILL_IL T I F-FFIl •..T= TTTTr v-,,r-- rT, - *~' ~,' .- r-T ON T.fl *IW hLIL. 7

Station 19 Shot Location: At apex Record: 19-1 Spread: L with #12 and #13 Date: 21 Dec., 1957 15 m from apex Shot Depth: 9 m Geophones: Vertical Charge: 200 g TNT Sensitivity: 9 Filters: LC KK30, HC KK215 O

Station 21 Shot Location: At apex Record: 21-2 Spread: L with #12 and #13 Date: 23 Dec., 1957 15 m from apex Shot Depth: 8 m Geophones: Vertical Charge: 200 g TNT Sensitivity: 9 Filters: LC KK30, HC KK215

=-m-- - - - m mM Mm-- I m m m m m - m m m- m m m m - m m - Smm

R'

C'

Station 22 Shot Location: At apex Record: 22-3 Spread: L with #12 and #13 Date: 24 Dec., 1957 15 m from apex Shot Depth: 9 m Geophones: Vertical Charge: 200 g TNT Sensitivity: 7 Filters: X KK30, HC KK215 t'3

Station 23 Shot Location: At apex Record: 23-2 Spread: L with #12 and #13 15 m from apex Date: 30 Dec., 1957 Geophones: Vertical Shot Depth: 9 m Sensitivity: A G C, ultimate -30, initial 0 Charge: 200 g TNT Filters: LC KK30, HC KK215

m ------m ------I - ON

• . " . .. f

' ______f - - - I"__ ' " L ' I . " ' ' " I...... ______L - --- - . . .• " ______,._ _ ., ...i ",,.. ":'., '-5- ,, lr ,______,... %,:.., v, , iii T"___-'_"___-__...__'7 ,_[ ___ POW4L

Station 24 Shot Location: 15 m from #24 Record: 24-2 Spread: In line Date: 2 Jan., 1958 Geophones: Vertical Shot Depth: 9 m Sensitivity: 9 Charge: 200 g TNT Filters: LC KK30, HC KK215 R

-- -- ou . .N.,.% -v

.. ...F\- ."...v

rep., 0' 10 V,--**%,..r,,v ,;-%.Wt.

Is• . . . "V*%. - ., -

Station 26 Shot Location: At apex Record: 26-3 Spread: L with #12 and #13 15 m from apex Date: 8 Jan., 1958 Geophones: Vertical Shot Depth: 9 m Sensitivity: 8 Charge: 200 g Filters: LC KK30, HC KK215

- - - - m -m ------m - - - I m r - -m----rn ------Irm

R

0~, t -, 0^00,44 $nw

*~. ' IV~ I 91~ ...... ri,t.j I ~ ;LWA W~J r,'+l"J'][i_.. • A ~~~!L : W-WA WW,0JW'-Vlp t.n 4I.... ±~fl: --"w ]-w r,'U' ''I b IN I1 . i. MW 'indA IT".7 +.. ,,'4I'm'+],,,+,t,"..., _ '.1 r.v" .g ,,. ,, .-,. . I T ~i 0!'. It~ --rf*l lif 041toidwbio AL t:~~ ~

. II, va. i *I m Fur

______J -~---4 -*.~-- ~, 1rt

Station 27 Shot Location: At apex Record: 27-1 Spread: L with #12 and #13 15 m from apex Date: 14 Jan., 1957 Geophones: Vertical Shot Depth: 9 m Sensitivity: 9 Charge: 200 g Filters: LC KK30, HC KK215 ~,1' ~\t Ai... >AA

/N~ ~

JNyN~7NY~N

3v dv

ol...... 1 /NIN N ,,,,", /'k \jA

• m

300 Lv 100 Lv 30 iiv

Oscillator Test Record Frequency: 30 cps Sensitivity: 8 (sensitivity range in 10 db steps)