Another effusive activity generated the Carb�n Qullu lavas " ( Carbon Kollu ) " and finally the Pukara lava dome, whose collapse generated the Thuwas Ventilla pyroclastic flow.
12.
Other than that, potassium-argon dating has indicated effusive activity between 20 and 14 million years ago with a peak between 12.2 and 3.9 million years ago.
13.
The middle unit, which is early Amazonian in age, makes up the flanks of the main Alba edifice and records a time of more focused effusive activity consisting of long tube-and channel-fed flows.
14.
Throughout its history, volcanic activity at Furnas has been essentially explosive but eruptive styles have varied from mild effusive activity to at least two caldera-forming eruptions 30, 000 and 12, 000-10, 000 years ago.
15.
On the rim of the caldera left by this eruption is a lava dome complex named the Old Complex Unit . 0.3 ?0.1 mya ago effusive activity commenced with the Pre-platform and Platform units that were then followed by a tectonic event that dissected these units.
16.
The volcano originated as a stratovolcano in the Garigliano rift valley, with a group of eructive mouths spread in a area; later an effusive activity concentrated in the central area, forming a volcanic cone some 1, 800 m-high, mostly formed of tephra and accompanied by minor cones such as the Monte Ofelio at south-west.
