deception Island is an island in the South Shetland Islands close to the Antarctic Peninsula with a large and safe natural harbor. This island is the caldera of an active volcano, which seriously damaged local scientific stations in 1967 and 1969. The island previously held a whaling station; it is now the most popular tourist destination with over 15,000 visitors per year. Two research stations are operated by Argentina and Spain during the summer season. While various countries have asserted sovereignty, it is still administered under the Antarctic Treaty System.
Telefon Bay
Looking WSW from the center of the caldera
Located within the Bransfield Strait, the island is roughly circular and horseshoe-shaped, with a maximum diameter around 15 km (9.3 mi). The highest peak, Mont Pond on the east side of the island, has an elevation of 539 m (1,768 ft), while Mount Kirkwood on the west has an elevation of 452 m (1,483 ft). Over half (57%) of the island is covered by glaciers up to 100 m thick, ice-cored moraines, or ice covered pyroclasts. The centre of the island has been flooded by the sea to form a large bay, now called Port Foster, about 10 km (6.2 mi) long and 7 km (4.3 mi) wide. The bay has a narrow entrance, just 500 m (1,640 ft) wide, called Neptune's Bellows. The port is a basin with a flat floor up to 170 m (560 ft) deep with several small submarine cones and domes. The port is rimmed by a shallow coastal shelf with sandy-gravelly beaches. The outer coast of the island is characterized by 30–70 m (98–230 ft) cliffs of rock or ice.
Raven's Rock, a navigation hazard, lies 2.5 m (8.2 ft) below the water in the middle of the channel. Just inside Neptune's Bellows lies the cove Whalers Bay, which is bordered by a large black sand beach. Several maars line the inside rim of the caldera, with some containing crater lakes (including one named Crater Lake). Others form bays within the harbour, such as the 1 km (0.6 mi) wide Whalers Bay. Other features of the island include Mount Kirkwood, Fumarole Bay, Sewing-Machine Needles, Telefon Bay, and Telefon Ridge.
A 2016 study on Ardley Island, 120 km (75 mi) to the northeast, examined lake guano sediments and studied penguin population dynamics over 7,000 years. Three of five population growth phases were terminated by a sudden crash, due to volcanic eruptions from the active volcano of Deception Island.[4][5] The history of volcanic eruptions is still under investigation, but several larger eruptions happened in the last 10,000 years.[6]
Geology
Deception Island is the exposed portion of an active shield volcano 30 km in diameter. The island is associated with Bransfield Basin seafloor spreading that includes a volcanic ridge and seamounts dating back to the Pleistocene. Deception Island volcanic ash layers have been found on other South Shetland Islands, the Bransfield Strait, the Scotia Sea and in South Pole ice cores. Volcanic tremors are common, originating from depths less than 10 km. Historical eruptions occurred in 1839–42, 1967, 1969, and 1970.[3]: iii Stratigraphy of the island is characterized by the pre-caldera Port Foster Group and the post-caldera Mount Pond Group, both within the Deception Island Volcanic Complex. The Port Foster Group's principal outcrops are located at South Point, Cathedral Crags near Entrance Point and north of Punta de la Descubierta forming spectacular coastal cliffs along the western portion of the island. The group is composed of the Fumarole Bay Formation consisting of hydrovolcanic tephra, the Basaltic Shield Formation consisting of lavas and Strombolian scoria, and the Outer Coast Tuff Formation consisting of lapilli-tuffs. The Mount Pond Group dominates the surface geology and consists of the pyroclastic Baily Head and Pendulum Cove formations, both formed during hydrovolcanic eruptions, and the Stonethrow Ridge Formation consisting of tuff cone and maar deposits. The caldera collapsed as either a hydrovolcanic eruption of the Outer Coast Tuff Formation, releasing about 30 cubic kilometers of magma, or passively due to regional tectonics, since the island is at the intersection of the Bransfield Strait rift and the orthogonal Hero Fracture Zone.
History
1829 map
The first authenticated sighting of Deception Island was by the British sealers William Smith and Edward Bransfield from the brig Williams in January 1820. It was first visited and explored by the American sealer Nathaniel Palmer on the sloop Hero the following summer, on 15 November 1820. He remained for two days, exploring the central bay.[10] Palmer named it "Deception Island" on account of its outward deceptive appearance as a normal island, when the narrow entrance of Neptune's Bellows revealed it rather to be a ring around a flooded caldera.
Palmer was part of an American sealing fleet from Stonington, Connecticut, under the command of Benjamin Pendleton, consisting of 6 ships. Port Fisher
mapa de Isla Decepcion
