tailieunhanh - EARTH SCIENCES - Notable Research and Discoveries Part 5

Tham khảo tài liệu 'earth sciences - notable research and discoveries part 5', khoa học tự nhiên, địa lý phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 76 EARTH SCIENCES Molokini a volcanic crater that forms a crescent-shaped island near Maui Hawaii Ron Chapple Getty Images steady entrenched in the mantle and the plate will move past it. Plates move slowly in a range of one to six inches cm a year but over millions of years this movement is significant. Wilson s theory suggested that the chain of Hawaiian islands were formed from this volcanic activity in a manner that reflects the movement of the plate. As the plate lingers over the hot spot the volcanic activity builds a seamount which gradually rises above the surface to create an island. After some period of time as the plate moves on another island in the chain forms slightly behind the earlier island. Wilson published his theory in a report A Possible Origin of the Hawaiian Islands in a 1963 issue of the Canadian Journal of Physics. Kilauea is a highly active volcano located on the island of Hawaii the Big Island . According to Wilson s theory the islands farthest from the current hot spot should be the oldest since they were formed much earlier. Kauai the most northwestern of the major islands in the chain has rocks as old as 5 million years. This age contrasts with the Big Is-land the most southeastern island in which the oldest known rocks Volcanoes and Hot Spots 77 are less than 1 million years. The ages of the other islands also agree with the theory. Hawaiian volcanoes have been extremely important not only for volcanologists interested in hot spot theory but also for legions of tourists and interested onlookers. Native islanders have been observing these volcanoes for many generations and the British explorer Captain James Cook 1728-79 sighted the Hawaiian Islands in 1778. Written records of Kilauea began in 1790 showing that the volcano has been active for most of the past two centuries. In periods of high activity such as during eruptions or when lava rises to a visible level Kilauea draws a crowd. People such as Mark Twain 1835-1910 who .