Fig. 8.40. Intraformational conglomerate of oil-cemented sand cobbles on a Lower Cretaceous fluvial channel floor, adjacent to the Mupe Bay paleo-seep, Dorset. (For further details see Selley, 1992b).
l ......
,
-
..~......--~..~.'-. :..
Shale flake conglomerate
Fig. 8.41. Intraformational conglomerate of claystone pellets. The channel cuts through a clay unit, demonstrating the penecontemporaneous origin of the conglomerate.
Table 8.4
Nomenclature of Conglomerates
I.
Texture
II. Composition
III. Source
Orthoconglomerate- grain-supported
Paraconglomerate (syn. diamictite)-- mud-supported
Polymictic-- pebbles composed of several rock types
Oligomictic--pebbles composed of one rock type
Intraformational--pebbles originate within the basin
Extraformational (syn. exotic)--pebbles extrabasinal in origin
There is no satisfactory classification of conglomerates. Nomenclature and description are based on the criteria of texture, composition, and source.