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The Waikato and King Country regions of New Zealand are built upon a basement of greywacke rocks, which form many of the hills. Much of the land to the west of the Waikato River and in the King Country to the south has been covered by limestone and sandstone, forming bluffs and a karst landscape. The volcanic cones of Karioi and Pirongia dominate the landscape near Raglan and Kawhia Harbours. To the east, the land has been covered with ignimbrite deposits from the Taupo Volcanic Zone. Large amounts of pumice from the Taupo Volcanic Zone have been deposited in the Waikato Basin and Hauraki Plains. ==Basement rocks== As with most of New Zealand, the basement rocks of the Waikato Region and King Country are composed of greywacke (indurated sandstone, siltstone and mudstone). The Waipa Fault passes north–south through the Waikato-King Country region, from Taupiri, along the Waipa River, and south to near Ohura. It represents a major dividing line between different terranes. Murihiku Terrane greywacke lies beneath the Waikato-King Country region on the western side, and outcrops to the west of the Waipa Fault, from south of Waikato Heads to Awakino. The Murihiku Terrane is considered to be an accretionary wedge of mainly volcanogenic forearc sediments. It was formed in Late Triassic to Late Jurassic times (220-145 Ma). A line of Maitai-Dun Mountain Terrane rocks are assumed to pass north–south along the Waipa Fault, through the centre of the Waikato-King Country region, separating the Murihiku Terrane and Waipapa Composite Terrane, and produce a detectable junction magnetic anomaly, but only outcrops at one place, at Wairere. Some Murihiku rocks occur to the east of the junction magnetic anomaly, forming the Taupiri and Hakarimata Ranges, but it is assumed that these rocks have been shifted to their present position. The Waipapa Morrinsville Terrane greywacke lies beneath the Waikato-King Country region on the eastern side, south of the Hunua Ranges, and east of the Waipa Fault. It was formed in Late Jurassic to Early Cretaceous times (160-120 Ma). 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 Waikato-King Country Region」の詳細全文を読む スポンサード リンク
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