| James Ross Island Volcanic Group | |
| Type: | Group |
| Age: | Cenozoic |
| Prilithology: | Alkali basalts |
| Otherlithology: | Hawaiites, benmoreites, mugearites |
| Namedfor: | James Ross Island |
| Region: | Antarctica |
The James Ross Island Volcanic Group is a stratigraphic unit of Cenozoic age distributed on James Ross Island and Vega Island of the James Ross Island group, the Tabarin and Trinity peninsulas of Graham Land and surrounding islands in the Prince Gustav and Antarctic sounds.[1]
The volcanic group consists predominantly of alkali basalts with minor hawaiites, benmoreites and mugearites. They are interpreted to have been deposited by volcanic eruptions in an extensional back-arc setting after subduction had ceased along the western margin of the Antarctic Peninsula. K–Ar dating of these rocks suggest that they were erupted from about 7 million years ago up until about a few hundred thousand years ago.[1] However, volcanic rocks as young as only a few thousand years old may exist on James Ross Island.[2]
Rocks of the James Ross Island Volcanic Group comprise Surtseyan tuff cones and Strombolian cinder cones, as well as lava deltas and overlying subaerial lava flows.[1] The dominating feature of the James Ross Island Volcanic Group is Mount Haddington, a massive shield volcano of Miocene-to-Pliocene age on James Ross Island.[2] [3]
The James Ross Island Volcanic Group includes the following geological formations:[4]
The James Ross Island Volcanic Group includes the following volcanic features:[4]