McNeill, Donald F. (1997): Facies and early diagenetic influence on the depositional magnetization of carbonates

Leg/Site/Hole:
Identifier:
1997-072400
georefid

10.1130/0091-7613(1997)025<0799:FAEDIO>2.3.CO;2
doi

Creator:
McNeill, Donald F.
Rosenstiel School of Marine and Atmospheric Science, Marine Geology and Geophysics, Miami, FL, United States
author

Identification:
Facies and early diagenetic influence on the depositional magnetization of carbonates
1997
Geology (Boulder)
Geological Society of America (GSA), Boulder, CO, United States
25
9
799-802
Rock-magnetic data from a core (Clino) on the margin of Great Bahama Bank show that both depositional facies and early diagenesis contribute to preservation of depositional remanent magnetization. This primary magnetization, carried by single-domain magnetite, and resultant directional data recorded in carbonates are influenced by diagenetic alteration that is largely controlled by facies and to a lesser degree relative sea level. Although polarity does not change, there is usually inclination shallowing relative to the axial dipole value, and the inclination values are more dispersed as a result of cementation. Four magneto-diagenetic zones were identified in Clino; from top down, these are (I) a low-Mg calcite, a cemented, shallow-water facies with dispersed inclinations, relatively high remanence coercivity, and magnetostatic interaction; (II) an upper-slope facies, moderately cemented, that has original aragonite mineralogy, produced more statistically consistent inclination angles, lower magnetostatic interactions and coercivity, and higher remanence intensity; (III) a cemented, lower-slope facies having characteristics of both the overlying zones, but containing some dolomite and abundant fractures; and (IV) a partially dolomitized, basal lower-slope interval with magnetic characteristics (dispersed inclination, weaker intensity, higher coercivity, higher magnetostatic interaction) similar to the shallow-water facies. The relatively uncomplicated diagenetic history, excellent age control, and depositional facies provide a spectrum of magnetization destructive processes and characterization of polarity data from platform carbonates.
English
Serial
Coverage:Geographic coordinates:
North:25.0000
West:-79.0000East: -78.3000
South:24.3000

Oceanography; anhysteretic remanent magnetization; Atlantic Ocean; carbonate sediments; cementation; Cenozoic; Clino Core; cores; depositional remanent magnetization; diagenesis; early diagenesis; facies; Great Bahama Bank; isothermal remanent magnetization; magnetization; marine sediments; North Atlantic; paleomagnetism; remanent magnetization; sediments; zoning;

.