In 1983 three directional surveys were made in the bore hole from which a deep ice core was obtained in the summers of 1979–81. The inclination and azimuth of the bore hole were measured on three surveys, temperature was included on two surveys, fluid pressure and hole diameter on one of the surveys. Fluid-pressure measurements show that the ice-overburden pressure was undercompensated in the upper few hundred meters and overcompensated at the bottom of the hole. Diameter measurements show closure in the upper portion and expansion near the bottom beginning at the transition from the Holocene to Wisconsin ice at 1784 m. The hole expansion and increase in inclination correlate with dust and silt content in the Wisconsin ice. Changes in azimuth are due to flow of the ice and are consistent with the direction of flow at the surface. Temperature measurements show that the hole is at or near equilibrium. The gradient of 0.012 K/m below 1400 m is less than the 0.018 K/m at Camp Century. There is a slight reduction in gradient near the bottom from internal friction in the silty ice.

In 1983 three d irec ti o nal su rveys were m ade in th e bore hole from whi ch a dee p ice core was o bta ined in the sum mers of 1979-8 1. The in clin a tion and azim ut h of th e bo re ho le were measured o n three surveys, tem perature was in cluded on two surveys, nuid press ure a nd ho le diameter on o ne of th e surveys. Fl uid-pressu re measu remen ts show th at th e iceoverbu rden pressure was undercom pensated in the uppe r few hundred meters a nd overcompensated at the bo tt om of th e ho le. Dia meter measure mf' nts sh ow cl osure in th e uppe r porti o n and ex pa nsio n nea r th e bo tt om begin ning at the trans ition from th e Ho locene lO Wisconsin ice at 1784 m. Th e hole expansion and in crease in in clin ati on correla te wi th d ust and sil t content in the \\'isconsin ice. C ha nges in azimuth are d ue to Row oflhe ice an d a re co nsis tent wi th the direc ti on of Aow at the surface. Temperatu re measure m e nts show that th e ho le is a t or nea r eq uilib rium. Th e g radient of 0,012 K /m below 1400 In is less th a n the 0.018 K/m a t Ca m p Century.T here is a sl ig ht reduction in grad ient near the bottom from internal fricti on in the silt y ice. (Rand, 1980), and the hole was drilled from 8l.7 m to the bottom with an electromechani cal drill (Gundestrup and others, in pres s). The drill, using neither melting nor solve nt s , produ c es a hole with a uniform diameter. The hol e i s filled with a liquid in order to minimize hole closure from the overburden pre s sure of the ice. R ESU ME. Relevis dll trOll deJorage a DyeA fter the dri 11 i ng s t opped in 1980 at 901 m, a temperature profile "was meas ured. Shortly before the end of the 1981 s eason, an inclination profile (Gundestrup and others, in press) was obtained using the inclinometers in the drill. The ne xt day the drill was trapped at the bottom while drilling in silty ice. Fo ur hundred liters of per c hlorethylene (pCEl were added to the hole, and the drill was left with tension in the cable. In 1982, the drill had become loose. After recovery of the drill, a temperature profile wa s measured. Soni c logging wa s performed (Tay lor, unpubli s hed) and a 5 m by 0.08 m probe was used as radar target in an attempt to measure the azi muth of the hole inclination s , and the velocity of radar wave s in ice (Jeze k and Roeloffs, 1984). In 1983 three indepe ndent bore-hole surveys were made usin g different tools to measure inclina- tion and azimuth. The hol e diameter, fl uid temperature, and pressure were also measured.While drilling, depth was measured as accumulated core length. The hole length changes with time due to the ice movement. In this work all slant hole depths measured on the logging winch in 1983 were scaled to comply with the 198 1 core length which we believe to be the most accurate meas urement of the lengt h of the hole. This corresponds to a true vert i cal depth (TVD) of 203 3. 2 m as the difference between s lant hole length and TVD was 4.4 m in 198 1. In 1983, the difference was 7.4 m.At the end of ...

A hole was drilled through the Ross Ice Shelf 450 kilometers from the barrier. Scientific sampling through this hole revealed a sparse population of crustaceans, fish, and microbial biomass. The seabed consists of mid-Miocene glaciomarine mud. Geothermal heat flow is average. Oceanographic data indicate an active circulation and melting at the base of the ice.

An Airy-type geophysical experiment was conducted in a 2-km-deep hole in the Greenland ice cap at depths between 213 and 1673 m to test for possible violations of Newton's inverse-square law. An anomalous gravity gradient was observed. We cannot unambiguously attribute it to a breakdown of Newtonian gravity because we have shown that it might be due to unexpected geological features in the rock below the ice.PACS numbers: 04.80,+z, 04.90.+e, 93.30.Kh Some unified field theories 1 raise the possibility that forces exist in nature with ranges on the order of 10 2 -10 5 m and coupling strengths close to that of gravity. If they exist, these new forces would be apparent as violations of Newton's inverse-square law. Recent geophysical measurements in a mine 2 and on a tall television antenna 3 have reported small deviations from the classical law. This paper describes a geophysical experiment to search for possible finite-scale, non-Newtonian gravity over a vertical distance of 213-1673 m in the glacial ice of the Greenland ice cap. The principal reason for the choice of experimental site is that the uniformity of the ice eliminates one of the major sources of uncertainty arising in the first of the earlier studies, 2 namely, the heterogeneity of the rocks through which the mine shaft passes. Our observations were made at Dye 3, Greenland, in a 2033-m-deep borehole, which reached the basement rock. The site is 60 km south of the Arctic Circle, 125 km inland from Greenland's east coast, and at a 2530-m elevation.The Newtonian prediction of the gravity profile in the borehole, based on a density model of the ice and the topographic relief of the bedrock developed from geophysical measurements, was compared with measured values. Differences in gravity g were measured at several depths z and modeled bylaboratory experiments, p, is the ice density, and g r is a correction to the gravity differences based on the attraction of the subice terrain. (The effect of the ice-surface topography is negligible.) Although Eq. (1) is adequate within the uncertainties of our experiment, a more exact expression 4 which accounts for p, ?=^p/(z), /« y(z), and the Earth's ellipticity was used in the calculations. The gravity anomaly Ag is defined as the difference between the modeled gravity g m and the observed gravity in the borehole g obs , Ag=g obs (z)-g m (z) .(2)where / is the theoretical free-air gravity gradient, G is the Newtonian gravitational constant as determined in Now we describe the steps taken to obtain the experimental observations and model calculations given in Table I. The uncertainties in this table include contributions from the measurements themselves and from imperfect knowledge of the ice density and the terrain, with the latter effect dominating. They do not reflect our ignorance of the density inhomogeneities in the underlying rock. This issue, which in the end has the least controlled systematic uncertainty, will be discussed below.Before the measurements were made in Greenland, the borehole gravity meter was...