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The Raukumara Region of New Zealand corresponds to the East Cape of the North Island, and associated mountain ranges. To the east of the North Island is the Hikurangi Trough, a collision zone between the Pacific Plate and the Australian Plate. The Pacific Plate is being subducted under the Australian Plate, compressing the east of the North Island, and causing the North Island Fault System, and a series of SSW-NNE trending basins and ranges, including the Raukumara Range. Successively newer rocks have been accreted to the east coast. The Raukumara Region used to be adjacent to Northland, before being shifted to its current position, and many rocks of the two regions match. To the north of the Raukumara Range lies the Bay of Plenty, formed of Torlesse (Waioeka) Greywacke. The central ranges are covered by in-place and allochthonous (displaced) Cretaceous to Oligocene rocks. To the south are more recent, mainly Miocene and Pliocene, rocks. ==Basement rocks== All basement rocks beneath the Raukumara Region belong to the Torlesse Composite (Waioeka) Terrane, of late Jurassic to early Cretaceous age (150-100 Ma). They are largely composed of Greywacke (hardened sandstone and mudstone), that accumulated in a deep marine environment. These rocks are exposed to the north of the Raukumara Range, from Whakatane to Papatea Bay. 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「Geology of the Raukumara Region」の詳細全文を読む スポンサード リンク
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