Fault structure and detailed evolution of a slow spreading ridge segment: the Mid-Atlantic Ridge at 29°N

Details Fault structure and detailed evolution of a slow spreading ridge segment: the Mid-Atlantic Ridge at 29°N Fault structure and detailed evolution of a slow spreading ridge segment: the Mid-Atlantic Ridge at 29°N

Jan 1998

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1998e%26psl.154..167s&link_type=abstract

Earth and Planetary Science Letters, vol. 154, Issue 1-4, pp.167-183

Computer Science

20

Mid-Atlantic Ridge, Median Valley, Sea-Floor Spreading, Acoustical Surveys, Magnetic Anomalies, Faults

Scientific paper

We present preliminary results of a detailed near-bottom study of the morphology and tectonics of the 29°N "Broken Spur" segment on the slow spreading Mid-Atlantic Ridge, using principally the TOBI deep-towed instrument. The survey covered two-thirds of the segment length, including all of its southern non-transform boundary, and extended off-axis of 40 km (3.3 Ma) on either side. We obtained nearly complete near-bottom sidescan sonar coverage and deep-towed three-component magnetic observations along 2-km-spaced E-W tracks. Sidescan data reveal new details of fault structure and evolution. Faults grow by along-axis linkage. In the inside corner, they also link in the axis-normal direction by curving to meet the next outer (older) fault; this leads to wider-spaced faults compared to segment centre or outside corner. Outward facing faults exist but are rare. The non-transform offset is characterised by faults that are highly oblique, not parallel, to the spreading direction, and show cross-cutting relations with ridge-parallel faults to the north, suggesting along-axis migration of the offset. Almost all volcanic activity occurs within 5 km of the axis. Most fault growth is complete within 15 km of the axis (1.2 Ma), though large scarps continue to be degraded by mass-wasting beyond there. Crustal magnetisation is strongly three-dimensional. The current neovolcanic zone is slightly oblique to earlier reversal boundaries, and its magnetisation rises to a maximum of 30 A m -1 near its southern tip. The central magnetisation high tapers southwards and is asymmetric, with a sharp western but gradual eastern boundary. We infer a highly asymmetric accretion of layer 2 near the segment end. Older magnetic anomalies are kinked and sometimes missing. We interpret these observations as evidence of a rapid, 18 km southward migration of the segment boundary during the past 1.8 Ma, and present a series of reconstructions illustrating this tectonic history.

Affiliated with

Also associated with

No associations

Rating

Fault structure and detailed evolution of a slow spreading ridge segment: the Mid-Atlantic Ridge at 29°N does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Fault structure and detailed evolution of a slow spreading ridge segment: the Mid-Atlantic Ridge at 29°N, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fault structure and detailed evolution of a slow spreading ridge segment: the Mid-Atlantic Ridge at 29°N will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1655102