Open AccessPalaeomagnetic Studies of Miocene Ignimbrites from Nevada
Author(s) -
Gose Wulf Achim
Publication year - 1970
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.1970.tb06068.x
Subject(s) - geology , polarity (international relations) , paleomagnetism , demagnetizing field , paleontology , geometry , mineralogy , magnetization , physics , magnetic field , chemistry , mathematics , biochemistry , quantum mechanics , cell
Summary A detailed palaeomagnetic study of a single ignimbrite shows marked variations in intensity, susceptibility, Koenigsberger ratio Q , and direction of magnetization. The behaviour of the intensity and Q can in part be explained as a change in grain size. A second profile through part of the same flow agrees well in its scalar properties, but the directions are very different. Six to fourteen samples have been collected from each of six additional ignimbrites in the same sequence. Their magnetic stability has been established by a.c. demagnetization and by lateral consistency over a distance of 60 km. Of all flows four are normally magnetized while the remainder have reversed polarity. The palaeomagnetic poles of two of these ignimbrites lie at 33°N and 49°N, the others lie within 20° of the rotational pole. Six of these ignimbrites have K‐Ar ages between 29.7 and 17.8 My.