ISSN:
1365-246X
Quelle:
Blackwell Publishing Journal Backfiles 1879-2005
Thema:
Geologie und Paläontologie
Notizen:
To evaluate suggestions from earlier work that a reversal of magnetization is present in the Rajmahal Traps of mid-Cretaceous (probable Aptian) age in north-eastern India, we have sampled a 140 m thick section comprising a minimum of nine flow units at 25 sites in the north-western part of the outcrop. A coherent N→R→N magnetostratigraphy is identified, with evidence for transitional behaviour at the top and bottom of the succession.The mean characteristic remanence direction of the reversed sites (D/I= 145.7°/63.5°, α95= 6.0°) is approximately antiparallel to that of the normal polarity sites (D/I = 300.2°/-55.7°, α95= 12.4°), and the group mean confirms a palaeomagnetic pole position near 125°E, 9°S (A95= 10.5°) for the time of eruption of the traps. From 40Ar/39Ar evidence that the Rajmahal-Bengal Traps were emplaced over a short interval at ca, 117 Ma, we interpret the brief reversed episode identified near the base of the succession as a record of the JSEA event. The polarity evidence therefore supports the view that the Rajmahal Traps were fed by the Crozet Hotspot at the beginning of the Cretaceous Normal Superchron (∼ 119–83 Ma).
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1111/j.1365-246X.1996.tb07030.x
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