Sheathfolds in rheomorphic ignimbrites

@article{Branney2004SheathfoldsIR,
  title={Sheathfolds in rheomorphic ignimbrites},
  author={Michael J. Branney and Tiffany L. Barry and Martha M. Godchaux},
  journal={Bulletin of Volcanology},
  year={2004},
  volume={66},
  pages={485-491}
}
Structural reappraisal of several classic rheomorphic ignimbrites in Colorado, Idaho, the Canary Islands and Italy has, for the first time, revealed abundant oblique folds, curvilinear folds and sheathfolds which formed during emplacement. Like their equivalents in tectonic shear-zones, the sheathfold axes lie sub-parallel to a pervasive elongation lineation, and appear as eye structures on rock surfaces normal to the transport direction. With the recognition of sheathfolds, ignimbrites… 
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References

SHOWING 1-10 OF 16 REFERENCES
A reappraisal of ignimbrite emplacement: progressive aggradation and changes from particulate to non-particulate flow during emplacement of high-grade ignimbrite
We propose a mechanism by which massive ignimbrite and layered ignimbrite sequences — the latter liable to have been previously interpreted as multiple flow units-form by progressive aggradation
Marine emplacement of welded ignimbrite: the Ordovician Pitts Head Tuff, North Wales
The Pitts Head welded ignimbrite records a subaerial, large‐volume eruption and associated pyroclastic current that flowed into the sea. The current 15 km from source was steadily sustained with high
Geology of the peralkaline volcano at Pantelleria, Strait of Sicily
Situated in a submerged continental rift, Pantelleria is a volcanic island with a subaerial eruptive history longer than 300 Ka. Its eruptive behavior, edifice morphologies, and complex, multiunit
Distinguishing strongly rheomorphic tuffs from extensive silicic lavas
High-temperature silicic volcanic rocks, including strongly rheomorphic tuffs and extensive silicic lavas, have recently been recognized to be abundant in the geologic record. However, their
Quartz latite rheoignimbrite flows of the Etendeka Formation, north-western Namibia
The Etendeka Formation of north-western Namibia consists of a sequence of interbedded quartz latites and tholeiitic basalts and forms part of the Karoo Igneous Province in southern Africa. The age of
Pyroclastic rocks and calderas associated with strongly peralkaline magmatism
Strongly peralkaline volcanic complexes tend to be shieldlike due to coalescence of low-viscosity lavas from numerous vent areas and blanketing by pyroclastic flows and falls. Dense welding and
Laminar Viscous Flowage Structures in Ash-Flow Tuffs from Gran Canaria, Canary Islands
At least $$100 km.^{3}$$ of trachytic and peralkaline soda rhyolitic ash flows were erupted during late Miocene to early Pliocene time from a source near the center of Gran Canaria, Canary Islands.
...
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