About This Item

Share This Item

The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 37 (1953)

Issue: 9. (September)

First Page: 2119

Last Page: 2162

Title: Rational Theory of Delta Formation

Author(s): Charles C. Bates (2)

Abstract:

From the approach of the geological oceanographer, this paper attempts to develop rational lines of reasoning for hindcasting how nature disposed of sediments brought into a lake or ocean at a particular place and time. By assuming the ocean to be a currentless, tideless, wave-free basin, jet theory as developed by Tollmien and subsequent workers is utilized in determining the magnitude and interrelations of limnological and oceanographic phenomena observed off mouths of sediment-laden rivers. To do this, the basic theory of jets is modified by introducing a rotating fluid system and postulating a hydraulic head at the orifice.

If a delta is defined as a sedimentary deposit built by jet flow into or within a permanent body of water, these modifications allow for the existence of three basic types of deltaic deposits, depending on the density contrast between entraining and entrained fluids. Examples of these different types of inflow are cited from the Mississippi Delta region. In the case of hyperpycnal inflow (inflow more dense), it is suggested that turbidity currents carrying coarse-grained material during glacial stages eroded the Mississippi Submarine Canyon and supplied the material for the submarine delta off the canyon's mouth. Homopycnal inflow (inflow equally dense), which gives rise to the deltaic deposit characterized by classical top-, fore-, and bottom-set beds, is described for the Lake Ponch rtrain, Louisiana, area when the Bonnet Carre Floodway is in operation and for crevasses in the Lower Mississippi River. Hypopycnal inflow (inflow less dense) is discussed in some detail, including such aspects as flocculation effects, lunate bar development at river mouths, development of distributaries and flank depressions, the seaward movement of river water upon leaving the river's mouths, and effects of the earth's rotation. Modifying effects of wind, waves, and tides on deltaic deposits are discussed briefly.

Pay-Per-View Purchase Options

The article is available through a document delivery service. Explain these Purchase Options.

Watermarked PDF Document: $14
Open PDF Document: $24

AAPG Member?

Please login with your Member username and password.

Members of AAPG receive access to the full AAPG Bulletin Archives as part of their membership. For more information, contact the AAPG Membership Department at [email protected].