10.6084/m9.figshare.3453632.v1
Emanuele Roni
Emanuele
Roni
David Scott Westerman
David Scott
Westerman
Andrea Dini
Andrea
Dini
Carl Stevenson
Carl
Stevenson
Sergio Rocchi
Sergio
Rocchi
Feeding and growth of a dyke–laccolith system (Elba Island, Italy) from AMS and mineral fabric data
Geological Society of London
2016
flow paths
laccolith layers
results show
Strong correlation
AMS data
feeder dykes
field relationships
magma displacement direction
subhorizontal intrusions
Elba Island
flow pathways
tabular particles
magma flow
aid interpretation
mineral fabric data Dykes feed laccoliths
coalescing pulses
magma spread laterally
felsic San Martino laccolith displays
magma flow pathways
influence AMS results
sanidine megacrysts
feeder dyke
Geology
2016-06-21 11:34:09
Journal contribution
https://geolsoc.figshare.com/articles/journal_contribution/Feeding_and_growth_of_a_dyke_laccolith_system_Elba_Island_Italy_from_AMS_and_mineral_fabric_data/3453632
<p>Dykes feed laccoliths and sills; however, the link between feeder and intrusion is rarely observed. The felsic San Martino
laccolith displays a clear feeder–intrusion link, allowing reconstruction of the influence of the size and location of feeder
dykes on magma flow during formation of subhorizontal intrusions. This work uses anisotropy of magnetic susceptibility (AMS)
combined with mineral shape-preferred orientations of sanidine megacrysts to examine magma flow pathways through feeders into
a laccolith. Strong correlation between AMS and K-feldspar datasets indicates that alteration affecting the paramagnetic mineralogy
did not influence AMS results. The well-established field relationships between feeder and laccolith provided a robust ‘geo-logical’
model for flow pathways that we have used as a framework to aid interpretation of AMS data. The position and size of the main
feeder dyke helped to predict the flow paths in the overlying laccolith. Our results show that magma spread laterally from
the feeding system and built the laccolith layers with propagating and inflating divergent flow where tabular particles became
aligned perpendicular to the magma displacement direction. The lack of internal discontinuities indicates that the magma was
injected as a single pulse or a series of quickly coalescing pulses.
</p>