--> ABSTRACT: Quantitative Morphological Analysis of the Northwest Atlantic Mid-Ocean Channel (NAMOC); Comparison with Other Channels and Implications for Flow Conditions, by Ingo Klaucke, Reinhard Hesse, William B. F. Ryan, David J. W. Piper; #91020 (1995).

Datapages, Inc.Print this page

Quantitative Morphological Analysis of the Northwest Atlantic Mid-Ocean Channel (NAMOC); Comparison with Other Channels and Implications for Flow Conditions

Ingo Klaucke, Reinhard Hesse, William B. F. Ryan, David J. W. Piper

The NAMOC is a 100-200 m deep, 1.4-5 km wide and 3800 km long sinuous deep-sea channel. Based on channel geometry three segments can be distinguished:

1. A low sinuosity "equilibrium channel" characterised by up to 100 m high depositional levees: Channel gradient in this segment is 1:1000 and meander radii 17-34 km. The geometry of the channel apparently is in equilibrium with turbidity currents flowing in the channel as average depth, cross-sectional area of the channel and flow velocities constrained by channel geometry decrease strongly in this segment.

2. A very low sinuosity "modified equilibrium channel": Channel gradient in this segment averages 1:2000 and meander radii range from 30 to 60 km. At the confluence with tributaries the channel geometry is altered through levee breaching, erosion and chute pool formation.

3. A straight to medium sinuosity, "basement-controlled channel" developed south of 53°N, where the course of the NAMOC is constrained by oceanic fracture zones and seamounts with an average channel gradient of 1:2000 and no free meanders.

Compared to other submarine channels, rivers and channels on Mars and Venus, the NAMOC behaves generally similar to other sinuous channels, except for being narrower for a given wavelength and more sinuous for given dimensions. According to flume studies the sinuosity of subareal channels is related to channel gradient and the ratio of suspended load to bedload. Although the sinuosity of the NAMOC is low in absolute terms, it appears to be larger than predicted from other submarine channels. This might be related to the high proportion of suspended load transport, which is also evidenced by the build-up of important depositional levees from turbidity current spill-over.

AAPG Search and Discovery Article #91020©1995 AAPG Annual Convention, Houston, Texas, May 5-8, 1995