Magmatic lull

A magmatic lull is a period of declined magmatic activity in volcanically active regions. They may occur as a result of underthrusting of hinterland lithosphere beneath a volcanic arc, changes in subduction parameters such as relative velocity, direction and slab dip (e.g. flat slab subduction),^[1] arc-arc collisions^[2] and subduction hinge advance.^[1] Individual magmatic lulls may last tens of millions of years between periods of volcanicity.^[1][2]

Magmatic lulls can be related to volcanic gaps, which are regions lacking volcanic activity that separate two distinct volcanic zones. For example, the Andean Volcanic Belt of South America has three major volcanic gaps: the Peruvian flat-slab segment (3 °S–15 °S), the Pampean flat-slab segment (27 °S–33 °S) and the Patagonian Volcanic Gap (46 °S–49 °S).^[3]

References

1. Schleiffarth, W.K.; Darin, M.H.; Reid, M.R.; Umhoefer, P.J. (2018). "Dynamics of episodic Late Cretaceous–Cenozoic magmatism across Central to Eastern Anatolia: New insights from an extensive geochronology compilation". Geosphere. 14 (5). Geological Society of America: 1990–2008. ISSN 1553-040X.
2. Johnson, Kenneth H.; Schwartz, J.J.; Žák, Jiří; Verner, Krystof; Barnes, Calvin G.; Walton, Clay; Wooden, Joseph L.; Wright, James E.; Kistler, Ronald W. (2015). "Composite Sunrise Butte pluton: Insights into Jurassic–Cretaceous collisional tectonics and magmatism in the Blue Mountains Province, northeastern Oregon". Late Jurassic Margin of Laurasia: A Record of Faulting Accommodating Plate Rotation. Vol. 513. Geological Society of America. pp. 377–398. doi:10.1130/2015.2513(10). ISBN 9780813725130.
3. Stern, Charles R. (2004). "Active Andean volcanism: its geologic and tectonic setting". Revista Geológica de Chile. 31 (2). National Geology and Mining Service: 161–206. ISSN 0716-0208.