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The andesite line is the most significant regional geologic distinction in the Pacific Ocean basin. It separates the mafic basaltic volcanic rocks of the Central Pacific Basin from the partially submerged continental areas of more felsic andesitic volcanic rock on its margins.
Along the rim of the Pacific Basin are convergent plate boundaries often referred to as the andesite line since orogenic andesite is associated with this boundary. This line is often, but erroneously, confused with the boundaries of either the Pacific plate or the Pacific basin; the andesite line, however, also includes the Juan de Fuca, Cocos ...
A line of Dun Mountain-Maitai Terrane rocks are assumed to pass north–south along the Waipa Fault, [1] 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.
QAPF diagram with basalt/andesite field highlighted in yellow. Andesite is distinguished from basalt by SiO 2 > 52%. Andesite is field O2 in the TAS classification.. Andesite is an aphanitic (fine-grained) to porphyritic (coarse-grained) igneous rock that is intermediate in its content of silica and low in alkali metals.
In 1912, geologist Patrick Marshall introduced the term "Andesite Line" to mark a boundary between islands in the southwest Pacific, which differ in volcano structure and lava types. The concept was later extended to other parts of the Pacific Ocean. [20] The Andesite Line and the Ring of Fire closely match in terms of location. [21]
Patrick Marshall coined the terms andesite line and ignimbrite in the early 1900s while working in the TaupÅ Volcanic Zone. Harold Wellman discovered the Alpine Fault and its 480 km offset in 1941. Even though Wellman proved that large blocks of land could move considerable distances, the New Zealand geological survey was largely a late ...
Smaller andesite blocks for stone facing and carvings came from quarries within the Copacabana Peninsula about 90 kilometres (56 miles) away from and across Lake Titicaca from the Pumapunku and the rest of the Tiwanaku Site. [3] [5] An example of high-precision small holes Unfinished (upside down) block of andesite with blind holes. On finished ...
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