H漫画

24 samples of surface sediment from the lower Nova Scotia Slope (2000 - 5000 m depth) are analyzed for benthic foraminiferal content, along with over 100 samples from an 11 m piston core and corresponding gravity core from the same area, at 4046 m depth.

Analysis of the surface samples reveals the presence of 4 assemblages, apparently related to the corresponding ambient water masses. Assemblage I (2000 - 2500 m) is strongly dominated by Elphidium excavatum forma clavata and follows the range of Labrador Slope Water in the study area. Assemblage II (2500 - 3000 m) is a very diverse fauna with up to 70% agglutinated forms, and appears to be associated with North Atlantic Deep Water (NADW). Assemblage III is present on the slope from 3600 - 4000+ m, and is characterized by a strong presence of Epistominella umbonifera. Its areal extent seems to reflect the distribution of Antarctic Bottom Water (AABW) on the lower slope. Assemblage IV,, occurring from 4000+ m down to at least 4925 m (the lower limit of sampling), is a relatively impoverished benthic foraminiferal fauna dominated by small numbers of Saccammina difflugiformis. This biota may be subject to "abyssal storms" described by Hollister and McCave (1984) and exists within the "Cold Filament" water described by Weatherley and Kelley (1982).

Study of the core samples reveals dramatic changes in benthic foraminiferal populations at the sample site through time. The upper 30 or 50 cm of the piston core contain a fairly typical Assemblage III fauna (Epistominella umbonifera dominating), while below 90 cm the core is composed largely of sediments closely resembling the Facies 3b and 4 material described by Piper (1974) from cores in the same region. These sediments contain an assemblage not seen in any surface material, dominated by Elphidium excavatum forma clavata (a smaller, somewhat different variety from that seen in surface Assemblage I samples), Uvigerina peregrina and a few other forms, along with small numbers of an extinct Maastrichtian species, strong evidence of a turbiditic origin for these strata.

Indications are that these changes in fauna reflect the evolution of hydrographic conditions at the core site from the late Pleistocene to the present.

Keywords:
Pages: 213
Supervisor: F. Gradstein / Graham Williams

听

Day of the Mastodon

In October, 1991, the nearly complete skeleton of a young male
mastodon was unearthed in a gypsum quarry in East Milford, Nova
Scotia. Day of the Mastodon presents a fictionalized biography of that
animal as it lived and died some 70,00 years ago. Recreated from
research on what is known of mastodon biology, the tale blends fiction
and science into a plausible, fascinating chronicle of the life of one
individual from a now-extinct species. The animal's early years with a
small family herd of elders and cousins are described in intimate detail,
as are interactions with other prehistoric creatures that shared its
Pleistocene environment.

The mastodon's horrific death, and its aftermath, complete this
compelling and unusual nature story from our dim past.

F.C. Thomas is currently the manager of GSC
Atlantic's MicroAnalysis Facility at BIO in Dartmouth,
N.S. A Halifax native, his childhood fascination
with nature and the science of paleontology
led to an M.Sc. in Geology from H漫画
University. He has written scientific papers on
various invertebrate fossil groups, but this is his
first work of fiction.

Published 1996 - Lancelot Press - All rights reserved.

听

听