10.6084/m9.figshare.3453137
Alan P. M. Vaughan
Alan P. M.
Vaughan
Craig Storey
Craig
Storey
Simon P. Kelley
Simon P.
Kelley
Tiffany L. Barry
Tiffany L.
Barry
Michael L. Curtis
Michael L.
Curtis
Synkinematic emplacement of Lassiter Coast Intrusive Suite plutons during the Palmer Land Event: evidence for mid-Cretaceous
sinistral transpression at the Beaumont Glacier in eastern Palmer Land
Geological Society of London
2016
Palmer Land New
Palmer Land Event
deformation
biotite
Eastern Palmer Land Shear Zone
emplacement
Ma
Beaumont Glacier shear zone
Beaumont Glacier
Phase 1
quartz tonalite cuts
Lassiter Coast Intrusive Suite plutons
transpression
quartz tonalite sheet margin
cooling
NW
sinistral
evidence
Lassiter Coast Intrusive Suite magmatism
dyke
Ar
Geology
2016-06-21 11:10:11
Dataset
https://geolsoc.figshare.com/articles/dataset/Synkinematic_emplacement_of_Lassiter_Coast_Intrusive_Suite_plutons_during_the_Palmer_Land_Event_evidence_for_mid-Cretaceous___sinistral_transpression_at_the_Beaumont_Glacier_in_eastern_Palmer_Land/3453137
<p>New structural and geochronological data from the Eastern Palmer Land Shear Zone, in the vicinity of Beaumont Glacier, provide
the first evidence of dated structural control on emplacement of the 119–95 Ma, >13000 km<sup>2</sup> Cretaceous Lassiter Coast Intrusive Suite, during the accretionary mid-Cretaceous Palmer Land Event orogeny. A previously
undated >100 m thick dyke-like quartz tonalite intrusion was emplaced at 116.5 ± 1.5 Ma (Ar–Ar biotite cooling age) along
a NW–SE axis, coeval with NW–SE compressional deformation, and possibly controlled by sinistral transpression along the Beaumont
Glacier shear zone. The quartz tonalite preserves two styles of deformation and was probably progressively deformed by normal-sinistral
shearing during magmatic cooling with initial deformation of mafic enclaves in the dyke interior and final formation of proto-mylonite
to mylonite on the dyke margin. The quartz tonalite cuts folding associated with Phase 1 of the Palmer Land Event, indicating
that this folding is older than 116 Ma, extending the onset of Phase 1 back in time. Mylonite on the quartz tonalite sheet
margin was subsequently thermally reset at <em>c</em>. 107 Ma (Ar–Ar biotite method), during a peak in Lassiter Coast Intrusive Suite magmatism.
</p>