A SEARCH IN NORTH GREENLAND FOR A NEW ICE-CORE DRILL SITE

A new deep ice-core drilling site has been identified in north Greenla nd at 75.12 degrees N, 12.30 degrees W, 316 km north-northwest (NNW) o f the GRIP drill site on the summit of the ice sheet. The ice thicknes s here is 3085 mi the surface elevation is 2919 m. The North GRIP (NGR IP) site is identified so that ice of Eemian age (115-130 ka BP, calen dar years before present) is located as far above bedrock as possible and so the thickness of the Eemian layer is as great as possible. An i ce-flow model, similar to the one used to date the GRIP ice core, is u sed to simulate the flow along the NNW-trending ice ridge. Surface and bedrock elevations, surface accumulation-rate distribution and radio- echo sounding along the ridge have been used as model input. The surfa ce accumulation rate drops from 0.23 m ice equivalent year(-1) at GRIP to 0.19 m ice equivalent year(-1) 50 km from GRIP. Over the following 300 km the accumulation is relatively constant, before it starts decr easing again further north. Ice thicknesses up to 3250 m bring the tem perature of the basal ice up to the pressure-melting point 100-250 km from GRIP. The NGRIP site is located 316 km from GRIP in a region wher e the bedrock is smooth and the accumulation rate is 0.19 m ice equiva lent year(-1). The modeled basal ice here has always been a few degree s below the pressure-melting point. Internal radio-echo sounding horiz ons can be traced between the GRIP and NGRIP sites, allowing us to dat e the ice dawn to 2300 m depth (52 ka BP). An ice-flow model predicts that the Eemian-age ice will he located in the depth range 2710-2800 m , which is 285 m above the bedrock. This is 120 m further above the be drock, and the thickness of the Eemian laver of ice is 20 m thicker, t han at the GRIP ice-core site.