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The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 63 (1979)

Issue: 3. (March)

First Page: 465

Last Page: 465

Title: Resedimented Conglomerates in Submarine Channel, Miocene Flysch of Northern Appennines, Italy: ABSTRACT

Author(s): Hugh E. Hendry

Article Type: Meeting abstract

Abstract:

The Marnoso-arenacea Formation (Miocene) near Bologna contains a well-exposed, turbidite-filled channel. Conglomerates are restricted to the basal 50 m of the channel-fill sequence, where they are interbedded with sandstones and a few thin pelites. The beds were studied along an 800-m section running at a high angle to the trend of the channel axis, and although broad correlations can be made between closely spaced sections, individual beds generally cannot be traced from one section to the next. The conglomerate beds are pebble to cobble grade, and are up to 10 m thick; bases are sharp and commonly planar; tops have abrupt gradations to sandstones. Structures indicating bottom traction of clasts are absent, but imbrication of platy clasts indicates southeast-flowing curr nts. Most of the long axes of clasts plunge to the northwest. Most beds are clast supported, but in some, there are so many soft intraformational clasts that the clasts derived from outside of the basin are widely dispersed, and there is no well-developed clast fabric. Graded bedding is very uncommon, but individual beds are not texturally homogeneous from bottom to top. Abrupt changes in sorting, in places marked by layers of intraformational clasts, occur in many beds. In a few exposures, these changes coincide with gently inclined surfaces of lateral accretion. The clasts are considered to have been deposited rapidly from the bases of sandy turbidity currents. Individual beds of conglomerate likely were built by both lateral and vertical accretion of gravel layers deposited from sever l currents.

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