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Seafloor spreading magnetic anomalies south off Sri Lanka

DRS at CSIR-National Institute of Oceanography

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Title Seafloor spreading magnetic anomalies south off Sri Lanka
 
Creator Desa, M.
Ramana, M.V.
Ramprasad, T.
 
Subject Mesozoic magnetic anomalies
tectonic reconstruction
GEOSAT derived
Magnetic Quiet Zone
 
Description Results obtained from compilation and reinterpretation of about 21,200 line km of bathymetry, magnetic and satellite gravity data between 10oS to 10oN latitudes and 75 to 90oE longitudes south off Sri Lanka are presented here. Magnetic data and the synthetic seafloor spreading model reveal the presence of Mesozoic anomaly sequence M11 through M0 south of Sri Lanka. The oldest magnetic anomaly M11 (134Ma) occurs between 110 and 140 km away from the Sri Lankan coast. The seafloor created during the Early Cretaceous is estimated to have evolved with variable half-spreading rates ranging from 5.5 to 1.53 cm/yr. The trends of the fracture zones inferred from the offsets in the magnetic anomalies have been constrained using the satellite gravity mosaic. The Cretaceous Magnetic Quiet Zone (CMQZ, 121-84 Ma) crust between the isochrons M0 and A34 has an unequal width and widens from about 170 km in the west (80oE longitude) to about 500 km towards east (85oE longitude). Plate reconstruction models for 160 Ma (Fit), 134 Ma (M11), 121 Ma (M0) and 84 Ma (A34) are generated under the constraints of newly identified magnetic anomaly isochrons and fracture zones. The mismatch in the A34 reconstruction is attributed to the emplacement of the Ob, Lena and Marion Dufresne seamounts at the spreading ridge axis and/or the frequent ridge jumps in the Middle Cretaceous during the major plate reorganization.
 
Date 2006-07-14T07:12:30Z
2006-07-14T07:12:30Z
2006
 
Type Journal Article
 
Identifier Marine Geology, vol.229(3-4), 227-240pp.
http://drs.nio.org/drs/handle/2264/214
 
Language en
 
Rights An edited version of this paper was published by Elsevier Copyright [2006] Elsevier
 
Format 3517471 bytes
application/pdf
 
Publisher Elsevier