|
The Fra Mauro formation (or Fra Mauro Highlands) is a selenological formation on the near side of Earth's Moon that served as the landing site for the American Apollo 14 mission in 1971. It is named after the 80-kilometer-diameter crater Fra Mauro, located within it. The formation, as well as Fra Mauro crater, take their names from a 15th-century Italian monk and mapmaker of the same name. Apollo 13 was originally scheduled to land in the Fra Mauro highlands, but was unable to due to an in-flight technical failure. Fra Mauro is thought to have been formed from ejecta, or debris, from the impact which formed Mare Imbrium. During Apollo 14, the crew members sampled ejecta from Cone crater, a feature close in proximity to the immediate landing site of the mission, which provided insight into the composition of material deep inside the formation. Data from the mission has helped to determine the approximate age of Mare Imbrium, suggesting that it is no more than about 4.25 billion years old.〔 ==Formation and geography== Fra Mauro is a widespread hilly geological area covering large portions of the lunar surface around Mare Imbrium, and is thought to be composed of ejecta from the impact which formed Imbrium. The area is primarily composed of relatively low ridges and hills, between which exist undulating valleys. Much of the ejecta blanket from the Imbrium impact is covered with debris from younger impacts and material churned up by possible moonquakes. Debris found in the formation may have originated from deep beneath the original crust, and samples collected there could give insight into the geologic history of the Moon.〔 The petrology of the formation, based on data obtained on Apollo 14, indicates a history of impact and ejection possibly spanning over approximately 500 million years. A relatively recent impact created Cone crater, 1,000 feet across and 250 feet deep, near the landing site of Apollo 14. One of the main objectives of that mission was to sample the original Imbrium material located on its rim.〔 Samples obtained of the Fra Mauro formation during Apollo 14 suggest that the impact that formed the Imbrium basin is no older than 4.25 billion years.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Fra Mauro formation」の詳細全文を読む スポンサード リンク
|