| 词条 | Pirurayo |
| 释义 |
It is formed by several sequences of block and ash flows with subordinate lava flows which reach thicknesses of {{convert|640|m}}. They were erupted from possibly two vents, although the intense tectonic deformation makes it impossible to tell. These vents probably generated a compound volcano consisting of lava domes, which repeatedly grew and collapsed.[2] Pirurayo has erupted andesite and dacite, which belong to the potassium-rich volcanics series.[2] They probably formed from a mafic magma, which underwent assimilation of crustal materials and fractional crystallization. Volcaniclastic rocks from Pirurayo form part of the regional Moreta formation.[2] Volcanic activity occurred between 28 ± 3 and 20 ± 2 million years ago. The Pirurayo rocks were later influenced by faulting and hydrothermally altered.[2] References1. ^1 2 3 4 5 {{Cite journal|last=Soler|first=M. M.|last2=Coria|first2=B.|date=2002-06-01|title=Volcanismo oligoceno superior - mioceno inferior en la sierra de Pirurayo, Puna jujeña: estratigrafía y mecanismos eruptivos|url=http://www.scielo.org.ar/scielo.php?script=sci_abstract&pid=S0004-48222002000200005&lng=es&nrm=iso&tlng=en|journal=Revista de la Asociación Geológica Argentina|volume=57|issue=2|pages=160–172|issn=0004-4822|language=es}} [1]}}{{Jujuy-geo-stub}}{{Volcanology-stub}} 3 : Oligocene volcanoes|Miocene volcanoes|Volcanoes of Jujuy Province |
| 随便看 |
|
开放百科全书收录14589846条英语、德语、日语等多语种百科知识，基本涵盖了大多数领域的百科知识，是一部内容自由、开放的电子版国际百科全书。