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40Ar/39Ar isotopic dating of Etna volcanic succession
Author(s)
Language
English
Obiettivo Specifico
3.5. Geologia e storia dei vulcani ed evoluzione dei magmi
Status
Published
JCR Journal
JCR Journal
Peer review journal
Yes
Title of the book
Issue/vol(year)
3/130 (2011)
Publisher
Società Geologica Italiana
Pages (printed)
292-305
Issued date
2011
Keywords
Abstract
Since the 1970’s, about 50 radio-isotopic ages have been determined
on Etna volcanics using different techniques: Th-U and K/Ar.
Unfortunately, these ages cannot be readily used to constrain the
new stratigraphic setting of the volcano, because of the uncertainty
in sample locations or, sometimes, the large errors affecting the calculated
ages. For this reason a program of radio-isotopic dating
applying the 40Ar/39Ar incremental heating technique to date the
groundmass of basaltic samples has been carried out from 2002.
Forty samples (22 of which are of new publication) were collected
from key outcrops on Etna volcano, selected on the basis of their
stratigraphic position, while one sample was collected from the
Hyblean plateau volcanics. We have obtained reliable results from
all volcanics analysed from 542 ka up to 10 ka with the MSWD’s
(Mean Square of Weighted Deviates) ranging from 0.03 up to 1.7
excluding IS sample (MSWD = 6.28). These new results allow us to:
i) assign an age to 19 of the 25 lithostratigraphic units defined in the
new geological map of Etna volcano; ii) clarify the uncertain stratigraphic
position of isolated volcanic units; iii) constraint the temporal
hiatus that matches the main unconformities; iv) outline the
lapse of time between the end of the Hyblean volcanism and the
beginning of eruptive activity in the Etna region.
on Etna volcanics using different techniques: Th-U and K/Ar.
Unfortunately, these ages cannot be readily used to constrain the
new stratigraphic setting of the volcano, because of the uncertainty
in sample locations or, sometimes, the large errors affecting the calculated
ages. For this reason a program of radio-isotopic dating
applying the 40Ar/39Ar incremental heating technique to date the
groundmass of basaltic samples has been carried out from 2002.
Forty samples (22 of which are of new publication) were collected
from key outcrops on Etna volcano, selected on the basis of their
stratigraphic position, while one sample was collected from the
Hyblean plateau volcanics. We have obtained reliable results from
all volcanics analysed from 542 ka up to 10 ka with the MSWD’s
(Mean Square of Weighted Deviates) ranging from 0.03 up to 1.7
excluding IS sample (MSWD = 6.28). These new results allow us to:
i) assign an age to 19 of the 25 lithostratigraphic units defined in the
new geological map of Etna volcano; ii) clarify the uncertain stratigraphic
position of isolated volcanic units; iii) constraint the temporal
hiatus that matches the main unconformities; iv) outline the
lapse of time between the end of the Hyblean volcanism and the
beginning of eruptive activity in the Etna region.
Type
article
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