Diferència entre revisions de la pàgina «Lapil·li»

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== Formació==
[[File:Lapilli 850.jpg|thumb|esquerra|<center>Lapil·li de [[Fuerteventura]], [[Espanya]]</center>]]
Lapilli són spheroid-, de llàgrima, dumbbell- o gotetes en forma de botó de lava líquida o semi-fos expulsat d'una erupció volcànica que cauen a la terra al mateix temps, almenys parcialment fos. Aquests grànuls són no acreció, però en canvi el resultat directe de refrigeració roca líquida a mesura que viatja a través de l'aire.
Lapilli are spheroid-, teardrop-, dumbbell- or button-shaped droplets of molten or semi-molten [[lava]] ejected from a volcanic eruption that fall to earth while still at least partially molten. These granules are not accretionary, but instead the direct result of liquid rock cooling as it travels through the air.
 
''Lapilli are spheroid-, teardrop-, dumbbell- or button-shaped droplets of molten or semi-molten [[lava]] ejected from a volcanic eruption that fall to earth while still at least partially molten. These granules are not accretionary, but instead the direct result of liquid rock cooling as it travels through the air.''
Lapilli [[tuff]]s are a very common form of volcanic rock typical of [[rhyolite]], [[andesite]] and [[dacite]] pyroclastic eruptions, where thick layers of lapilli can be deposited during a basal surge eruption. Most lapilli tuffs which remain in ancient terrains are formed by the accumulation and ''welding'' of semi-molten lapilli into what is known as a [[Tuff#Welded tuff|welded tuff]].
 
toves lapilli són una forma molt comuna de roca volcànica típica de riolita, andesita i dacita piroclàstiques erupcions, on espesses capes de picó poden ser dipositats durant una erupció augment basal. La majoria de toves lapil·li que romanen en terrenys antics es formen per l'acumulació i soldadura de lapilli semi-fos en el que es coneix com una toba soldada.
The heat of the newly deposited volcanic pile tends to cause the semi-molten material to flatten out as it they becomes welded. Welded tuff [[rock microstructure|textures]] are distinctive (termed ''[[eutaxitic]]''), with flattened lapilli, [[fiamme]], blocks and bombs forming oblate to discus-shaped forms within layers. These rocks are quite indurated and tough, as opposed to non-welded lapilli tuffs, which are unconsolidated and easily [[eroded]].
 
''Lapilli [[tuff]]s are a very common form of volcanic rock typical of [[rhyolite]], [[andesite]] and [[dacite]] pyroclastic eruptions, where thick layers of lapilli can be deposited during a basal surge eruption. Most lapilli tuffs which remain in ancient terrains are formed by the accumulation and ''welding'' of semi-molten lapilli into what is known as a [[Tuff#Welded tuff|welded tuff]].''
 
La calor de la pila volcànica recent dipositat tendeix a fer que el material semifundido s'aplane, ja que es converteix soldades. textures de toves soldades són distintius (denominat eutaxitic), amb lapil·li aplanades, fiamme, blocs i bombes formen aplatat a les formes en forma de discus-dins de les capes. Aquestes roques són bastant endurida i resistent, a diferència de toves lapil·li no soldades, que són no consolidat i fàcilment erosionables.
 
''The heat of the newly deposited volcanic pile tends to cause the semi-molten material to flatten out as it they becomes welded. Welded tuff [[rock microstructure|textures]] are distinctive (termed ''[[eutaxitic]]''), with flattened lapilli, [[fiamme]], blocks and bombs forming oblate to discus-shaped forms within layers. These rocks are quite indurated and tough, as opposed to non-welded lapilli tuffs, which are unconsolidated and easily [[eroded]].''
 
=== Lapil·li de creixement ===
[[File:Accretionary Lapilli - geograph.org.uk - 831917.jpg|thumb|dreta|<center>Lapil·li de creixement del [[Mesoproterozoic]] [[Stac Fada Member]] del [[Torridonià]].</center>]]
tephra boles arrodonides es diuen lapil·li accretionary si consisteixen en partícules de cendres volcàniques. lapilli d'acreció es formen en una columna d'erupció o núvol per la humitat o forces electrostàtiques, amb la cendra volcànica de nucleació en un objecte i després acreció a ella en capes abans de la lapillus acreció cau del núvol. lapilli accretionary són com calamarsa volcàniques que formen mitjançant l'addició de capes concèntriques de cendra humida al voltant d'un nucli central.
Rounded [[tephra]] balls are called ''accretionary lapilli'' if they consist of [[volcanic ash]] particles. Accretionary lapilli are formed in an eruption column or cloud by moisture or electrostatic forces, with the volcanic ash nucleating on some object and then accreting to it in layers before the accretionary lapillus falls from the cloud. Accretionary lapilli are like volcanic hailstones that form by the addition of concentric layers of moist ash around a central nucleus.
 
''Rounded [[tephra]] balls are called ''accretionary lapilli'' if they consist of [[volcanic ash]] particles. Accretionary lapilli are formed in an eruption column or cloud by moisture or electrostatic forces, with the volcanic ash nucleating on some object and then accreting to it in layers before the accretionary lapillus falls from the cloud. Accretionary lapilli are like volcanic hailstones that form by the addition of concentric layers of moist ash around a central nucleus.''
This texture can be confused with [[spherulitic]] and [[axiolitic]] texture.
 
Aquesta textura es pot confondre amb la textura i esferulıtica axiolitic.
 
''This texture can be confused with [[spherulitic]] and [[axiolitic]] texture.''
 
=== Lapil·li blindat (o amb nucli) ===
Aquests són lapilli una varietat de lapilli d'acreció, tot i que contenen nuclis lítics o vidre recobertes per closques de gruixuda a fina cendra. lapilli blindats només es formen en erupcions hydroclastic, on la humitat significativa és present. La columna de vapor conté cendra cohesiva que s'adhereix a les partícules que el componen.
These lapilli are a variety of accretionary lapilli, though they contain lithic or crystal cores coated by rinds of coarse to fine ash. Armoured lapilli only form in hydroclastic eruptions, where significant moisture is present. The vapour column contains cohesive ash which sticks to particles within it.
 
''These lapilli are a variety of accretionary lapilli, though they contain lithic or crystal cores coated by rinds of coarse to fine ash. Armoured lapilli only form in hydroclastic eruptions, where significant moisture is present. The vapour column contains cohesive ash which sticks to particles within it.''
 
== Referències ==
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