Chaitén Volcano in the context of Rhyolite

In volcanology, a lava dome is a circular, mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano. Dome-building eruptions are common, particularly in convergent plate boundary settings. Around 6% of eruptions on Earth form lava domes. The geochemistry of lava domes can vary from basalt (e.g. Semeru, 1946) to rhyolite (e.g. Chaiten, 2010) although the majority are of intermediate composition (such as Santiaguito, dacite-andesite, present day). The characteristic dome shape is attributed to high viscosity that prevents the lava from flowing very far. This high viscosity can be obtained in two ways: by high levels of silica in the magma, or by degassing of fluid magma. Since viscous basaltic and andesitic domes weather fast and easily break apart by further input of fluid lava, most of the preserved domes have high silica content and consist of rhyolite or dacite.

Existence of lava domes has been suggested for some domed structures on the Moon, Venus, and Mars, e.g. the Martian surface in the western part of Arcadia Planitia and within Terra Sirenum.

Palena Province (Spanish: Provincia de Palena) is the southernmost administrative area in Chile's Los Lagos Region Los Lagos (X). The area is also called Continental Chiloe or Northern Patagonia, as geographers consider the Palena Province to be the starting point of Chilean Patagonia which extends south from Palena all the way to Tierra del Fuego. Palena Province is remote, beautiful, and difficult to access. In fact, Palena is one of the most sparsely populated provinces in the country and features a stunning geography characterized by steep fjords, wild rivers, hot springs, and numerous snow-capped volcanos. Chile's Austral Highway (Carretera Austral) is not continuous through the jagged geography of Palena Province. Motorists accessing the area by car are required to take two ferries across fjords to cross the province.

Historically, Chaiten was the provincial capital. Due to the eruption of Chaitén Volcano and the subsequent destruction of that town, Futaleufú was named the new provincial capital in March 2009. Major tourist attractions in Palena Province include the Pumalín Park, one of the largest established wilderness protection areas in the world, Yelcho Lake, and the Futaleufu River. Pumalin was the dream of the late US philanthropist and environmental activist Douglas Tompkins, it is nowadays called the Pumalin Douglas Tompkins national park after its founder. The park has excellent infrastructure for camping and is divided into two parts by the Huinay Ranch. Yelcho Lake is considered a prime destination for fly fishing. The Futaleufu River is considered by specialized media to be one of the three greatest whitewater runs in the world.