The Crozet islands were discovered by the expedition of French explorer Nicolas Thomas Marion-Dufresne. He sent his second in command, Julien Crozet, to land on the Île de la Prise de Possession (now Île de la Possession, Possession Island) on 24 January 1772.
Crozet then took possession of the archipelago in the name of France. It was James Cook who subsequently named these islands after Crozet, having given the name Marion (after Marion-Dufresne) to an isle in the Prince-Edward Islands.
The early 19th Century was a time when the Crozet islands were frequently visited by seal hunters, which drove these species almost to extinction by about 1835. Whaling was the major activity around these islands after that time. Shipwrecks near their shores were so common that from time to time the Royal Navy sent a ship to pick up possible survivors.
To reaffirm France’s sovereignty in the absence of any permanent occupation, the dispatch ship Bougainville was sent to Crozet in 1939. A ceremony was held on Possession Island and a stone bearing a bronze plaque was laid above the bay named Baie du Marin on the same occasion.
A French government decree of 21 November 1924 attached the Crozet, Kerguelen, Saint-Paul and Amsterdam islands to the Scattered Islands District dependent on the then French colony Madagascar’s province of Tamatave. Later, in 1955, they became a district of the French Southern and Antarctic Lands (TAAF) and thus formed a new Overseas Territory (TOM).
The islands are not subjected to extreme temperatures, but they are swept strongly by prevailing westerlies or northwesterlies. Often severe gale force or provoking terrific storms, access to the islands can be blocked for several days in succession. Wind speeds exceed 100 km/h for 100 days per year. Rainfall is extremely abundant (more than 2500 mm per year) and frequent: it rains 300 days per year on average. Average annual temperature is about 5°C. The seasons are not strongly marked; on the coast, temperature stays between -5°C and +15°C throughout the year.
The Crozet Islands lie on a large oceanic plateau extending 4500 km², limited by isobath -250 m. They are part of a broad volcanic massif, fragmented by tectonic movements causing much of it to collapse into the sea. Now the major reminders of this geological history appear in 2 distinct groups of islands:
• One to the west with the 12 Apostle islets, Pig Island and Penguin Island,
• One to the east, 100 km from the first group, with Possession Island and East Island.
The first group to appear was the eastern one, about 10 million years (Ma) BP and its volcanic activity was still alive some tens of thousands of years ago.
The western group came into being a little over 5 Ma BP. Its most recent edifice is Pig Island, less than 500 000 years old and where some very recent volcanic episodes (about 5000 years BP) produced a large crop of cinder cones.
Topographic maps of the Crozet Islands can be viewed on Géoportail de l’IGN