90 NATIONAL OCEANOGRAPHIC PROGRAM—1965 
SCIENTIFIC BACKGROUND OF DRILLING PROGRAM AS PRESENTED IN A PROPOSAL TO: 
THE NATIONAL SCIENCE FOUNDATION 
(Excerpts selected by F. F. Koezy from proposal written by C. Hmiliani, 
June 1964) 
The earth is a geophysical, geochemical, and biological system of such com- 
plexity that less is known about its structure, composition, and dynamics than. 
about those of most other celestial bodies. The complexity of the earth as a 
planet rests essentially upon a threefold basis: (1) its mass, large enough to: 
have permitted the differentiation of a core, mantle, and crust, and the produc- 
tion and retention of a substantial hydroatmosphere; (2) its heat balance, per- 
mitting surface water to exist in all three phases; and (3) its angular velocity 
and axis orientation resulting in a diurnal cycle of convenient frequency. <A 
perhaps unavoidable consequence of these things has been the development of 
life, a phenomenon of considerable interest even from a purely physicochemical 
point of view. 
Whereas processes operating over short-time intervals (up to a few hundred 
years) are easily studied by direct observation, those operating over longer time: 
intervals can be understood only if, in addition to direct observation (when feasi- 
ble), their effects through periods of time proportionate to their durations are: 
studied. Many of these effects are recorded in the sections of sedimentary rocks 
available in the upper crust. 
The thickness of soft sediments in “normal” ocean areas; that is, in the areas 
between the foot of the continental slopes and that of the midoceanic ridges, 
ranges from about 300 meters in the Pacific to about 10,000 meters in areas of 
the Atiantie. 
Three main types of sediments occur on the ocean floor. The most common 
is Globigerina-ooze, covering about 48 percent of the ocean floor and consisting 
essentially of a clay matrix with embedded abundant shells of planktonic Foram- 
inifera, skeletal elements of Coccolithophoridae, diatom valves, and skeleta of 
Radiolaria (see appendix). The clay matrix consists of the finest continental 
Getritus brought to the ocean by rivers and wind and distributed by ocean cur- 
rents. Magnetic spherules of cosmic origin are also abundant. 
The second type of sediment is red clay, covering about 38 percent of the ocean: 
floor. Red clay consists of the same matrix as Globigerina-ooze, but the eal- 
careous elements (foraminiferal shells and Coceclithcphoridae platelets) have: 
been removed by solution. This solution occurs on the portions of the ocean 
floor which are deeper than about 4,800 meters in the Atlantic and 4,300 meters 
in the Pacific. Before glaciation of Antarctica and subsequent cooling of the 
ocean bottom water (that is before a few million years ago) solution was prob- 
ably restricted to depths greater than those at which it occurs today. 
The third type of deep sea sediments is silica-ooze, consisting again of the 
usual clay matrix, but including large amounts of siliceous shells of Diatoms and 
Radiolaria. Diatom ooze is common at high southern latitudes in both the 
Atlantie and the Pacific, while Radiolaria ooze is restricted to a belt along the 
central and eastern equatorial Pacific. 
Deep sea sediments provide a record which, although most likely not continu- 
ous at any given place, is believed to be far more complete, for the time interval 
covered, than that provided by marine sediments outcropping on land. Further- 
more, deep sea sediments integrate the changing picture at the surface of the 
earth over very great areas, while epicontinental marine sediments are greatly 
influenced by conditions in the immediate neighborhood. Finally, cosmic ele- 
ments are remarkably concentrated in deep sea sediments, while they are enor- 
mously diluted in epicontinental sediments and nearly impossible to find and 
isolate. 
These considerations suggest that deep sea sediments are especially useful for 
rate studies; that is, for the study of the first and second derivatives, with 
respect to time, of a large number of geophysical, geochemical, and biological 
processes of regional, worldwide, and cosmic significance. The factors involved 
are the influx of various mineralogical and geochemical phases from the conti- 
nents and also from the water column above (by direct precipitation) ; the 
influx of biological phases from the water column above and the formation of 
such phases in situ; and the influx of cosmic elements from outer space (prin- 
cipally cosmic spherules, but also cometary material which may be detectable by 
solid-source mass-spectrometry ). 
