Open AccessMagnetic polarity stratigraphy of the Tertiary igneous rocks of Skye, Scotland
Author(s) -
Dagley P.,
Mussett A. E.,
Skelhorn R. R.
Publication year - 1990
Publication title -
geophysical journal international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0956-540X
DOI - 10.1111/j.1365-246x.1990.tb06577.x
Subject(s) - igneous rock , geology , stratigraphy , polarity (international relations) , radiometric dating , paleontology , geochemistry , tectonics , genetics , biology , cell
SUMMARY Palaeomagnetic results are given for 115 sites, mainly from the central igneous intrusive complex, and also radiometric dates by the 40 Ar −39 Ar step‐heating method. These are combined with published dates and palaeomagnetic results for the lavas and regional dyke swarms with the aim of establishing the magnetic polarity stratigraphy. Igneous activity spanned at least the approximate interval 61‐54 Ma, and a polarity sequence of at last R‐N‐R‐N‐R, but could span seven polarity intervals, R‐N‐R‐N‐R‐N‐R, depending on the age of the Loch Ainort Epigranite. However, these polarities cannot be identified with specific chrons of either the Harland et al. (1982) or Berggren et al. (1985) polarity time‐scales. The Skye igneous activity, therefore, spans more polarity intervals than in Mull, Ardnamurchan or Rhum and this is consistent with the radiometric ages. Interpretations of the results for the Coire Uaigneich and related granites and for the Loch Ainort Epigranite present problems, and partial solutions are offered.