23. 
GEOCHEMICAL INVESTIGATION 
Carbonate analyses, The carbonate analyses which give espe- 
cially the values of CaCO3 content of the sediments define to some extent 
the lithologic nature of the sediment in question, Over 300 analyses have 
been made, 
For the purpose of this report the following values are selected 
from a core composed of foraminiferal lutite: at the top of the core the 
CaCo3 content was 30%, at 60 cm, 34.3%, at 90 cm, 32%, at 110 cm, 
22, 8%, at 140 cm. 37. 8%. 
No final conclusions have been made, 
Natural radiocarbon (c!4) measurements, Under the direction 
of Dr, J. L. Kulp ee age determinations are made on selected samples 
from the upper parts of cores at the geochemistry laboratory, Lamont 
Geological Observatory, (See under Climatic Optimum, ) The method 
permits relatively precise age determination from the present back to 
about 30,000 years, ; 
Ionium method, This method of age determination is Based on 
the relative amounts of Uranium, ftenium, and Radium in deep sea cores, 
The experimental data consist of the variation of the radium content as a 
function of depth in a sediment, 
Measurements are being made on a variety of cores at the geo- 
chemistry laboratory, Lamont Geological Observatory, in an attempt to 
determine the type of core on which reliable ages can be obtained (Kulp, 
Volchok, Holland, Ericson, 1952), 
