Sedimentation of New Ocean Crust: The Mid-Atlantic Ridge, 37 deg N.
Abstract
A study of sediments from the FAMOUS area near 36 deg 50 min N lattitude on the Mid-Atlantic Ridge reveals a great range of physical, chemical, and biological parameters over a small area of the sea floor. Inside the rift valley, sediment cover patterns reflect asymmetrical spreading rates and general transport of sediments from topographic highs to low areas. A clear relationship between grain size and depth can be described by a simple linear function, with progressively finer sediments found at greater depths. The primary mechanism responsible for this distribution is thought to be gentle gravity transport of finer sediment fractions which are resuspended by bioturbation. Episodic processes, such as slumping, are believed to be less important to observed grain-size patterns than this slow but continuous process. Bottom currents are also active in the rift valley, but their primary effect is the localized formation of transient ripple and scour features. The CaCO3 content is anomalously low in rift valley sediments, probably because of dilution of calcareous sediments by volcanic debris. The high clay content in rift valley sediments suggests that this component is mainly very fine-grained. An examination of benthic foraminifera in the FAMOUS sediments reveals suprisingly high variability.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1979
- Accession Number
- ADA068306
Entities
People
- Nancy Sharman Marks
Organizations
- Stanford University