Minerals Report - International Seabed Authority

Basin groups are subdivided into types depending on their
geologic history and structural framework. In terms of geologic history,
basins are subdivided into cratonic, cratogenic, and post-platform,
collisional, subduction-related, and some other basin types. Cratonic
basins are those with Archean-Early Proterozoic basements, whereas
cratogenic basins are underlain by younger (Baikalian, Caledonian,
Hercynian and Mesozoic) basements. The basins located on micro
continents are interpreted as continental. Depending on basement ages,
they are classified as either cratonic or cratogenic.
In terms of structural framework, basins are subdivided into types
such as synclinorium; rift; block; intrafolded; folded platform; inner deepsea;
European-type pericontinental back arc; Pacific-type back arc, fore arc
and inter arc; marginal-sea; and some other basin types. Some types,
intrafolded for example, are divided into subtypes. Folded platform-type
basins related to foredeeps were recognized for the Alpine orogenic belts
only.
The basins of active oceanic margins – fore arc, inter arc, and back
arc – were recognized only at the junctions of the oceanic sectors of
lithospheric plates, for example, the Pacific and Indian-Australian plates;
the Philippine Sea and North American plate; the Caribbean and the North
and South American plates. At the junctions of oceanic and continental
plates, active continental margins were recognized without further
subdivision into fore arc, inter arc, and back arc basins.
The classification of sedimentary basins is supplemented by
geologic models of all recognized basin types, and correlated with the
classifications most frequently used in western countries 4, 5 .
Detailed investigation of basin structures and hydrocarbon
distribution based on the new classification enabled us to fulfil our
principle objective, a quantitative estimate of total hydrocarbon resources
in all prospective petroleum regions of the world.
A total of 120 petroliferous basins occur partly or entirely within
the abyssal zone of the World Ocean floor (figure 2). Deep-sea areas with
more than 500 m of seawater form parts of various basin types. These
include primarily those basin groups and types that are conveniently
classified as typically continental structures. Secondly, they include the
basins confined to the troughs and depressions in pericratonic sag zones
INTERNATIONAL SEABED AUTHORITY 488