Sedimentation rates calculated on surface sediment samples from different site of the Atlantic and Pacific Oceans (Table 1)

Radiocarbon ages on CaCO3 from deep-sea cores offer constraints on the nature of the CaCO3 dissolution process. The idea is that the toll taken by dissolution on grains within the core top bioturbation zone should be in proportion to their time of residence in this zone. If so, dissolution would shift the mass distribution in favor of younger grains, thereby reducing the mean radiocarbon age for the grain ensemble. We have searched in vain for evidence supporting the existence of such an age reduction. Instead, we find that for water depths of more than 4 km in the tropical Pacific the radiocarbon age increases with the extent of dissolution. We can find no satisfactory steady state explanation and are forced to conclude that this increase must be the result of chemical erosion. The idea is that during the Holocene the rate of dissolution of CaCO3 has exceeded the rain rate of CaCO3. In this circumstance, bioturbation exhumes CaCO3 from the underlying glacial sediment and mixes it with CaCO3 raining from the sea surface.

Oxygen and carbon isotope ratios for six planktonic foraminifer species from different water depth, Ontong-Java Plateau, Pacific (Table 2)

Stable isotope analyses and scanning electron micrographs have been carried out on six planktonic forminifera species, Pulleniatina obliquiloculata, Globorotalia tumida, Sphaeroidinella dehiscens, Globigerinoides ruber, Globigerinoides sacculifer and Globigerinoides quadrilobatus from eleven box-cores taken at increasing depths in the equatorial Ontong-Java Plateau (Pacific). This allows us to describe the way dissolution affects the microstructures of the tests of the different species and to quantify the changes of isotopic composition. We may conclude that: 1) dissolution effects on test morphology and stable isotope compositions are species dependent, species with a similar habitat showing a similar trend; 2) the shallow water, thin-shelled species are the first to disappear: scanning electron microscope (SEM) work shows alteration of outer layers. Deep water, thick-shelled species are present in all samples: SEM work shows breakdown and disparition of inner layers; 3) for all species there is a similar trend towards increasing delta18O values with increasing water depths and increasing dissolution. This effect may be as high as 0.6 ? per thousand meters for Globorotalia tumida; 4) below the lysocline, around 3500 m, it appears that 13C/12C ratios slightly increase towards equilibrium values for thick shelled species: G. tumida, P. obliquiloculata and S. dehiscens. 14C dates and isotope stratigraphy of two box-cores show that all samples are recent in age, and exclude upward mixing of glacial deposits as an important factor.

Orpheus: myths of the world.

Illustrated t.-p.

Orpheus glee book; a collection of glees selected from the best composers.

[v. 1] 1st tenor.--[v. 2] 2d tenor.--[v. 3] 1st bass.--[v. 4] 2d bass.--[v. 5] Piano.

Orpheus; Untersuchungen zur griechischen, römischen, altchristlichen Jenseitsdichtung und Religion,

Mode of access: Internet.