All holes drilled during Leg 114 (1987) of the Ocean Drilling Program (ODP) contained ice-rafted debris (IRD) as defined by Bornhold (1983). Samples from Hole 699A, Site 701, and Hole 704A were analyzed through mechanical laboratory techniques (Allman and Lawrence, 1972; and Head, 1980), and yielded a nearly complete history of ice-rafting episodes recorded at these drill sites. Approximately 20 cc of sediment taken about every 50 cm from cores of ODP Leg 114, Sites 699 and 701, and about every 150 cm from Site 704, were processed and analyzed for IRD content. The course fraction (250 mu m-2 mm) was isolated, split into representative subsamples, and examined under a binocular microscope to identify and count the various components. The ratio of biogenic to terrigenous material was determined and, in conjunction with sample volume, weight, and sedimentation rates, used to calculate the apparent mass-accumulation rate (AMAR) of IRD. The data generated from the analysis of fifty-two cores (444 plugs) provide the basis for this thesis. The first influx of IRD at Hole 699A on the northeastern slope of the Northeast Georgia Rise occurred at a depth of 69.94 meters below sea floor (mbsf) in sediments of early Miocene age ( approximately 20 Ma). This material is of the same type as early IRD, but represented only a small percentage of the coarse fraction. Minor amounts of IRD first reached Site 701 on the western flank of the Mid-Atlantic Ridge in the late Miocene (5.9 Ma). The first significant quantity of sand and gravel appeared at a depth of 107.76 mbsf (4.4 Ma), and is about the same age as at Hole 699A (4.5 Ma). Hole 704A on the southern portion of the Meteor Rise received very little or no IRD prior to 2.46 Ma. This was also the time of greatest influx of IRD at this hole, and correlates favorably with greatest influxes of IRD at Site 701 (2.44 Ma) and Hole 699A (2.48 Ma). These prominent peaks, recorded at all sites, are probably the Sirius-till equivalent.

West: -62.0000 East: 7.2515 North: 60.0000 South: -57.0000

West: NaN East: NaN North: NaN South: NaN

Expedition: 114

Site: 114-699

Site: 114-701

Site: 114-704

Provider: SEDIS Publication Catalogue

Data set link: http://sedis.iodp.org/pub-catalogue/index.php?id=1992-050732 (c.f. for more detailed metadata)

This metadata in ISO19139 XML format