The Greenland gravitational constant experiment

Journal Article · Mon Sep 10 04:00:00 EDT 1990 · Journal of Geophysical Research; (USA)

DOI:https://doi.org/10.1029/JB095iB10p15483· OSTI ID:6096396

Zumberge, M A; Parker, R L; Hammer, P; Sasagawa, G S; Stevenson, J M ^[1]; Ander, M E; Nieto, M M ^[2]; Lautzenhiser, T V; Wirtz, J ^[3]; Aiken, C L.V.; Ferguson, J F; Fisher, E; McMechan, G A ^[4]; Gorman, M R; Cooper, A P.R. ^[5]; Greer, J ^[6]; Hansen, B L ^[7]

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1. Univ. of California at San Diego, La Jolla (USA)
2. Los Alamos National Lab., NM (USA)
3. Amoco Production Co., Tulsa, OK (USA)
4. Univ. of Texas at Dallas, Richardson (USA)
5. Univ. of Cambridge (England)
6. Univ. of Colorado, Boulder (USA)
7. Univ. of Nebraska, Lincoln (USA)

An Airy-type geophysical experiment was conducted in a 2-km-deep hole in the Greenland ice cap at depths between 213 m and 1,673 m to test for possible violations of Newton's inverse square law. The experiment was done at Dye 3, the location of a Distant Early Warning Line radar dome and the site of the deepest of the Greenland Ice-Sheet Program (GISP) drill holes. Gravity measurements were made at eight depths in 183-m intervals with a LaCoste and Romberg borehole gravity meter. Prior to the experiment the borehole gravity meter was calibrated with an absolute gravity meter, and the wireline depth-finding system used in the borehole logging was calibrated in a vertical mine-shaft against a laser geodimeter. The density of the ice in the region was calculated from measurements taken from ice cores obtained from earlier drilling observations. Ice penetrating radar was employed in order to correct the gravity data for the topography of the ice-rock interface. Surface gravity observations were made to assess the extent to which density variations in the sub-ice rock could affect the vertical gravity gradient. The locations of the gravity observation points were determined with a combination of GPS recording, first-order leveling, and EDM surveying. An anomalous variation in gravity totaling 3.87 mGal (3.87 {times} 10{sup {minus}5} m/s{sup 2}) in a depth interval of 1,460 m was observed. This may be attributed either to a breakdown of Newtonian gravity or to unexpected density variations in the rock below the ice.

• OSTI ID: 6096396
• Journal Information: Journal of Geophysical Research; (USA), Journal Name: Journal of Geophysical Research; (USA) Vol. 95:B10; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
AIRY FUNCTIONS
BOREHOLES
CALIBRATION
CAVITIES
CLASSICAL MECHANICS
DENSITY
DEPTH
DIMENSIONS
DRILL CORES
EQUIPMENT
FUNCTIONS
GRAVITATION
GRAVITATIONAL FIELDS
GRAVITY LOGGING
GREENLAND
ICE
ICE CAPS
MEASURING INSTRUMENTS
MECHANICS
PHYSICAL PROPERTIES
RESERVOIR ROCK
WELL LOGGING
WELL LOGGING EQUIPMENT