Open AccessA palaeomagnetic study of the Upper Mesozoic succession in Northern Tunisia
Author(s) -
Nairn A. E. M.,
Schmitt T. J.,
Smithwick M. E.
Publication year - 1981
Publication title -
geophysical journal of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0016-8009
DOI - 10.1111/j.1365-246x.1981.tb02697.x
Subject(s) - cretaceous , geology , paleontology , mesozoic , sequence (biology) , outcrop , ecological succession , anomaly (physics) , magnetic anomaly , structural basin , genetics , physics , condensed matter physics , biology , ecology
Summary. The Upper Mesozoic section from Northern Tunisia provided an Upper Jurassic palaeomagnetic pole of 65.2°S 20.3°E α 95 = 6.1 calculated from the means of normal and reversely magnetized samples from the uppermost Callovian, Oxfordian, Kimmeridgian and Portlandian rocks. In general the only Cretaceous rocks to yield acceptable results were the few samples collected from fresh outcrops. A polarity sequence can be established for the Upper Jurassic which can be correlated with the oceanic Keathley anomaly sequence. One consequence of the proposed correlation of the oceanic anomaly with the terrestrial palaeomagnetic sequence is to suggest a slightly different age for the Oxfordian‐Kimmeridgian boundary. One interpretation of the frequent intermediate directions of magnetization in the Cretaceous sequence is that there may be a number of unrecognized short period reversals within the Cretaceous and, more particularly, during the so‐called Cretaceous normal period.