Central volcanoes as sources for the Antarctic Peninsula Volcanic Group

• Published in: Antarctic Science
• Main Authors: Leat, Philip T., Scarrow, Jane H.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 1994
• Subjects: Geology; Ecology, Evolution, Behavior and Systematics; Oceanography; Antarctic; The Antarctic; Antarctic Peninsula; Palmer Land; Edgell; Mount Edgell; Wright Spires; Zonda Towers; Antarc*; Antarctic Science
• Online Access: http://dx.doi.org/10.1017/s0954102094000568; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102094000568

From at least the Early Jurassic to the Miocene, eastward subduction of oceanic crust took place beneath the Antarctic Peninsula. Magmatism associated with the subduction generated a N-S linear belt of volcanic rocks known as the Antarctic Peninsula Volcanic Group (APVG), and which erosion has now exposed at about the plutonic/volcanic interface. Large central volcanoes from the APVG are described here for the first time. The structures are situated in north-west Palmer Land within the main Mesozoic magmatic arc. One centre, Zonda Towers, is recognized by the presence of a 160 m thick silicic ignimbrite, containing accidental lava blocks up to 25 m in diameter. This megabreccia is interpreted as a caldera-fill deposit which formed by land sliding of steep caldera walls during ignimbrite eruption and deposition. A larger centre, Mount Edgell-Wright Spires, is dominated by coarse-grained debris flow deposits and silicic ignimbrites which, with minor lavas and fine-grained tuffs, form a volcanic succession some 1.5 km thick. Basic intermediate and silicic sills c. 50 m thick intrude the succession. A central gabbro-granite intrusion is interpreted to be a high-level magma chamber of the Mount Edgell volcano.