Open Access40 Ar/ 39 Ar dates of eastern Iceland lavas
Author(s) -
Mussett A. E.,
ROSS J. G.,
Gibson I. L.
Publication year - 1980
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.1980.tb02579.x
Subject(s) - geology , plateau (mathematics) , stratigraphy , period (music) , paleontology , geochronology , tectonics , mathematical analysis , physics , mathematics , acoustics
Summary. Twenty‐two plateau ages obtained by the 40 Ar/ 39 Ar step‐heating method span most of the time of formation of eastern Iceland. With one exception the dates are consistent with the stratigraphy, the exception having a very unusual argon release pattern. It is concluded that the 40 Ar/ 39 Ar step‐heating method can give correct dates on hydrothermally altered samples the total fusion ages of which are not correct; however, it is not possible to conclude from the results obtained that the method is inherently more accurate than the conventional method using carefully selected samples. Though it is known from geological evidence that minor irregularities of spreading have occurred the results show that, within the resolution of the dates, spreading has been steady and symmetrical; in particular, neither a large eastward jump nor repetitive westward jumps can have occurred. The average half spreading rate for the period 2Myr to 12 Myr ago was 0.78 ± 0.16 cm yr‐ 1 .