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Geology of Réunion
Zircon 2:
Réunion is a [[mafic]] island formed as a result of the [[Réunion hotspot]] in the [[Indian Ocean]], the same hotspot that produced the massive basalt flows of the [[Deccan Traps]], when it was beneath India more than 66 million years ago.
==Stratigraphy & Tectonics==
The island of Réunion formed from two volcanoes, the active [[Piton de la Fournaise]] on the southern end of the island and [[Piton des Neiges]], which is slightly taller and dormant. <ref></ref> The Reunion hotspot that formed the Deccan Traps also produced the [[Chagos-Laccadive Ridge]] and the [[Mascarene Plateau]] and plays a role in the [[geology of Mauritius]] and [[Rodriguez Island]]. Isotopic dating in 1969 found that Réunion, Mauritius and Rodriguez all developed independently, but Réunion and Mauritius were much more closely related to the formation of the Mascarene Plateau. <ref></ref>
===Piton des Neiges===
[[Piton des Neiges]] is heavily eroded at the summit, nearly erasing its original crater, although it is surrounded by several smaller craters. Almost entirely [[basalt]], the mountain also has small units of [[andesite]], [[phonolite]] and [[trachyte]] with small alkaline [[syenite]] intrusions, forming dikes and sills.
In 1981, geologists suggested that volcanism at Piton des Neiges may be closely linked to regional [[structural geology]]. The main point of eruptive activity is associated with rift zone strike-slip faults and dike swarms around the mountain indicate cauldron subsidence. Structural characteristics help to explain the dramatic erosion of the central caldera, which collapsed due to [[graben]] formation. In addition, the eruption of younger lava flows may have emptied the magma chamber, helping to drive the collapse. <ref></ref>
There are very few sedimentary rocks on Réunion except for an uplifted block of calcareous rock at the base of Piton des Neiges.
===Piton de la Fournaise===
[[Piton de la Fournaise]] has two semi-circular craters, surrounding older craters. The volcano experiences a mix of [[Hawaiian eruption]] and [[Strombolitian eruption]] types and typically has highly liquid lava flows. When cooled, Piton de la Fournaise lavas form basalt enriched in [[labradorite]] with almost no [[olivine]]. Historic evidence indicates that the volcano erupts on a 20 to 40 year cycle. <ref></ref>
==Natural resource geology==
Although there are few economically valuable deposits on the island, small quarries supply the local building supply industry.
==References==
[[Category:Geology of Réunion| ]]
[[Category:Geology by country|Réunion]]
==Stratigraphy & Tectonics==
The island of Réunion formed from two volcanoes, the active [[Piton de la Fournaise]] on the southern end of the island and [[Piton des Neiges]], which is slightly taller and dormant. <ref></ref> The Reunion hotspot that formed the Deccan Traps also produced the [[Chagos-Laccadive Ridge]] and the [[Mascarene Plateau]] and plays a role in the [[geology of Mauritius]] and [[Rodriguez Island]]. Isotopic dating in 1969 found that Réunion, Mauritius and Rodriguez all developed independently, but Réunion and Mauritius were much more closely related to the formation of the Mascarene Plateau. <ref></ref>
===Piton des Neiges===
[[Piton des Neiges]] is heavily eroded at the summit, nearly erasing its original crater, although it is surrounded by several smaller craters. Almost entirely [[basalt]], the mountain also has small units of [[andesite]], [[phonolite]] and [[trachyte]] with small alkaline [[syenite]] intrusions, forming dikes and sills.
In 1981, geologists suggested that volcanism at Piton des Neiges may be closely linked to regional [[structural geology]]. The main point of eruptive activity is associated with rift zone strike-slip faults and dike swarms around the mountain indicate cauldron subsidence. Structural characteristics help to explain the dramatic erosion of the central caldera, which collapsed due to [[graben]] formation. In addition, the eruption of younger lava flows may have emptied the magma chamber, helping to drive the collapse. <ref></ref>
There are very few sedimentary rocks on Réunion except for an uplifted block of calcareous rock at the base of Piton des Neiges.
===Piton de la Fournaise===
[[Piton de la Fournaise]] has two semi-circular craters, surrounding older craters. The volcano experiences a mix of [[Hawaiian eruption]] and [[Strombolitian eruption]] types and typically has highly liquid lava flows. When cooled, Piton de la Fournaise lavas form basalt enriched in [[labradorite]] with almost no [[olivine]]. Historic evidence indicates that the volcano erupts on a 20 to 40 year cycle. <ref></ref>
==Natural resource geology==
Although there are few economically valuable deposits on the island, small quarries supply the local building supply industry.
==References==
[[Category:Geology of Réunion| ]]
[[Category:Geology by country|Réunion]]
June 03, 2018 at 06:22AM
