Aula Prática 2AeB Texturas Vulcanicas

7/25/2019 Aula Prtica 2AeB Texturas Vulcanicas

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TEXTURAS DAS ROCHAS VULCNICAS

I - LAVAS E INTRUSES SUBSUPERFICIAIS (RASAS)


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LAVAS E INTRUSES SUBSUPERFICIAIS (RASAS)

Textura: grau de r!"#a$!%!dade& #a'a% d" gr*" e +,ar!. (#ra'a& re$a/0e"ge'1#r!a"2 ,r'a e re$a/0e" '3#ua" e%#re " %"#!#u!%#e" da ra)4

I'5r#6%!a da #e7#ura: re,$e#e a" %d!/0e" de r!"#a$!8a/* (e4g4 re",r!a'e%#& ra8* de %u$ea/*&rde' de r!"#a$!8a/*44444)4

Grau de cristalinidade

H$r!"#a$!% (r!"#a!")H$!a$!% (9!dr)H!5r!"#a$!%() (r!"#a!" ; 9!dr)H!5!a$!%() (9!dr ; r!"#a!")

(*)#e7#ura de ra 9!dr e%#re ?:@ e :()#e7#ura de ra 9!dr e%#re : e @:?

Granulao (tamanho dos gros)

ra%u$a/* R"

Fina < 1 mm

Mdia 1 - 5 mm

Grossa 5 mm - 3 cm

Muito grossa > 3 cm


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Forma dos cristais:

Euedra$ ou !d!'r,! - refer to grains that arebounded by crystal faces

Suedra$ or "u!d!'r,! - are grains that arebounded by some crystal faces

A%edra$ ou 7e%'r,!- are deoid of crystal faces


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6. HBITO = FORMA


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!%era$ Ha!#"


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Granularidade Equigranular ou Inequigranular seriada ou porfirtica

Textura porfirtica gr!os maiores "fenocristais# em matri$ de granula%!o mais fina&

Matri$ ' com()e-se de cristais* idro ou ambos os com(onentes

+e,tura itrofrica - matri$ formada (or idro&

+e,tura glomero(orfirtica - fenocristais agru(ados em distintas .reas


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O$!9!%e 5Gr! a"a$# Pe%rG"#" , $!9!%e a%d a g$'errG"# , "'a$$er $!9!%e (5ur5$e)

a%d 5$ag!$a"e "e# !% a% !%#ergra%u$ar 'a#r!7 , 5$ag!$a"e a%d gra%u$ar 5Gr7e%e4 au!&Haa!!

Textura porfirtica e glomeroporfirtica com matriz intergranular


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Pr5Gr!#! r 5Gr! #e7#ure O$!9!%e 5e%rG"#" "e# !% a ,!%e-gra!%ed&

!%#ergra%u$ar 'a#r!74 Ru%d $ear "#ru#ure" are ga" 9e"!$e"4 O$!9!%e a"a$#,r' #e DPSP (Dee5 Sea Dr!$$!%g Prgra')4

Textura porfirtica com matriz intergranular


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HG5Ga$$!%e #e7#ure

Textura itrofrica


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O"!d!a% 9!#r5Gre - A 9!#r5Gre !" a%#er %a'e ,r a 5e%rG"#-ear!%g "!d!a%4 Te 5e%rG"#" !% #e 5#'!rgra5 are '"#$G

5$ag!$a"e4 Te gru%d'a"" !" 9$a%! g$a""4 Te 9!e !" u%der r""ed5$ar!8er"4 (Sa'5$e !" ,r' %#a%a4)

Textura itrofrica


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!olcanic gla"" "#o$ing perlitic texture %concentric cure& fracture"'. A (le( ofgla"" $it# clinop)roxene an& plagiocla"e i" locate& (elo$ an& to t#e rig#t of t#elarge plagiocla"e p#enocr)"t.

Textura perltica em roc#a itrofrica


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Ba"alt laa flo$* Ham&en* +onnecticut

Textura inter"ertal e intergranular em roc#a &e laa (a",ltica


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Textura tra-utica alin#amento "u(/paralelo &e plagiocl,"io em roc#a ulc0nica* forma&opor fluxo.


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/

Te7#ure gra%5Gr!4 ra%5Gr! #e7#ure !" a% !%#ergr# , =uar#8a%d a$a$! ,e$d"5ar4 I% #!" a"e& #e gra%5Gr! #e7#ure rad!a#e" u#

,r' $arge 5$ag!$a"e gra!%" ($er $e,#-graG& $er r!g#-graG>$a)4V!e !" u%der r""ed $ar!8er"4

Textura granofrica


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I12/34 Textura inter"ertal e intergranular. 5 277


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I12/:; Roc#a trea a criptocri"talina. Textura &e cri"tai" &e fel&"patoapre"entan&o a caracter"tica textura swallowtail,enoli&o" em i&ro e"curo. 89 277


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I12/:; Roc#a trea a criptocri"talina. Textura &e cri"tai" &e fel&"pato apre"entan&o a caracter"tica textura

swallowtail,enoli&o" em i&ro e"curo. 89 2


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I12/:; Roc#a trea a criptocri"talina mo"tran&o fratura" perltica. 89 277


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I12/:; Roc#a trea a criptocri"talina mo"tran&o e"cula". 5 277


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I12/:; Roc#a trea a criptocri"talina. Textura &e cri"tai" &e fel&"pato

apre"entan&o a caracter"tica textura swallowtail,enoli&o" em i&ro e"curo. 89 2


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I12/3:A Textura glomeroporfirtica* com matriz inter"ertal e intergranular. 8*;? 2


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I12/3:A Textura porfirtica* com matriz inter"ertal. 5 2


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I12/3:A Textura porfirtica* com matriz inter"ertal e intergranular.

O("erar -uanti&a&e" menore" &e i&ro. 5 2


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I12/38 Textura inter"ertal* intergranular a "u(oftica. !i&ro em parte

&eitrifica&o. 89 277


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I12/38 Textura inter"ertal* intergranular e "u(oftica. 89 2


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II - ROCHAS PIROCLJSTICAS (VULCANOCLJSTICAS)



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@ep"ito pirocl,"tico+la"to"%&imen"e"

em mm'Cirocla"to"

Principalmente inconsolidado:

TefraPrincipalmente consolidado:

Rocha piroclstica

bomba, blocoaglomerado

camadas de blocos ou bomba,

bloco tefra

aglomerado

brecha piroclstica

lapliestratos, camadas de lapli ou

tefra laplitufo lapli

cinza de granulao grossacinza grossa tufo (cinza) grosso

64

2

116

cinza de granulao fina(gro de p!) "inza fina (p!) #ufo (cinza) fino (tufo p!)

Ta(ela 8 $ Classificao e nomenclatura de piroclastos e depsitos piroclsticos bemselecionados baseadas nas dimenses dos clastos (Schmid, 191 ! recomendao da

"#$S%


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@imen"DomE&ia em

mm

Cirocl,"ticaTufito"

%mi"to pirocl,"tico/epicl,"tico'

picl,"tico%ulc0nica e7ou nDo

ulc0nica'

%glomerado,brecha piroclstica

#ufo lapli

"onglomeradostufceos, brechas tufceas

"onglomerado,&recha

%renitos tufceos %renito

'iltitos tufceos'iltito

64

2

116

126

#ufo (cinza)grosso

fino

%rgilas tufceas, folhelho %rgilito, folhelho

uantidadede material

piroclstico1** a + + a 2 2 a *

Ta(ela ; $ &ermos usados para rochas piroclsticas!epiclsticas mistas (Schmid, 191,recomendao da "#$S%


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PGr$a"#! ,$ de5"!#

5Gr$a"#! "ee# de5"!# "de(0sito de flu,o de cin$a e blocos#

@ it & & i l, t


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@ep"ito" por -ue&a &e pirocl,"to"

!ulcDo Gipari* It,lia


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PGr$a"#! ,$ de5"!#

P3'!e ,$ - de(0sito de flu,o de (mice ou ignimbrito

INIBRITO SOLDADO(Ke$ded !g%!'r!#e& A"& a5a%)

Many ignimbrites are hard* densly 2elded glassy rocs& +he (umice fragments that characteri$eunwelded ignimbrites* are not easily recogni$able in 2elded arieties because they hae beencom(acted into blac glassy (ancae sha(es* no2n as fiamme& 4ote the fiamme in the (hoto sho2nhere& fiamme-bearing ignimbrite is such as this is said to hae a eutaxitic te,ture& Courtesy of PeterFrancis.
http://www.geology.sdsu.edu/how_volcanoes_work/Thumblinks/ignimbrite_unwelded_page.htmlhttp://www.geology.sdsu.edu/how_volcanoes_work/Thumblinks/ignimbrite_unwelded_page.html


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Ignim(rito- uma rocha ou dep!sito formado por uma ou

mais unidades de flu.o piroclstico pumcio(p/mice flo0), independente de soldado ou no("as right, 13+)

1rau &e "ol&amento@a&o pela relaDo mE&ia &o comprimento %+p'pela altura %H em cm' &e fiame" e &e pJmice"

o("era&o" no &ep"ito. +p7H

Incipiente / 8>8 a ;>8 Mo&era&o / :*?>8 a ?>8

@en"amente "ol&a&o K?*?>8


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PGr$a"#! ,$ de5"!#

P3'!e ,$ - de(0sito de flu,o de (mice ou ignimbrito

INIBRITO SOLDADO(Ke$ded !g%!'r!#e& A"& a5a%)

Many ignimbrites are hard* densly 2elded glassy rocs& +he (umice fragments that characteri$eunwelded ignimbrites* are not easily recogni$able in 2elded arieties because they hae beencom(acted into blac glassy (ancae sha(es* no2n as fiamme& 4ote the fiamme in the (hoto sho2nhere& fiamme-bearing ignimbrite is such as this is said to hae a eutaxitic te,ture& Courtesy of PeterFrancis.

I12IMBRITO
http://www.geology.sdsu.edu/how_volcanoes_work/Thumblinks/ignimbrite_unwelded_page.htmlhttp://www.geology.sdsu.edu/how_volcanoes_work/Thumblinks/ignimbrite_unwelded_page.html


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I12IMBRITO
http://upload.wikimedia.org/wikipedia/commons/b/bc/Tuff_welded.jpg


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2elded #u,,

e$ded !g%!'r!#e

e$ded !g%!'r!#e

Te5ra
http://images.google.com/imgres?imgurl=http://www.geology.sdsu.edu/how_volcanoes_work/Images/Pyroflows/ignimbrite_welded_s.gif&imgrefurl=http://www.geology.sdsu.edu/how_volcanoes_work/Thumblinks/ignimbrite_page.html&h=116&w=180&sz=26&hl=en&start=6&tbnid=L3OykLMHfNlTPM:&tbnh=65&tbnw=101&prev=/images%3Fq%3Dwelded%2Bignimbrite%26gbv%3D2%26ndsp%3D20%26hl%3Den%26sa%3DNhttp://images.google.com/imgres?imgurl=http://upload.wikimedia.org/wikipedia/commons/thumb/b/bc/Tuff_welded.jpg/574px-Tuff_welded.jpg&imgrefurl=http://commons.wikimedia.org/wiki/Image:Tuff_welded.jpg&h=600&w=574&sz=175&hl=en&start=10&tbnid=OTu1iOsX6ZaPMM:&tbnh=135&tbnw=129&prev=/images%3Fq%3Dwelded%2Bignimbrite%26gbv%3D2%26hl%3Denhttp://images.google.com/imgres?imgurl=http://www.geol.umd.edu/~jmerck/nature/landscapes/images/tuff.s.jpg&imgrefurl=http://www.geol.umd.edu/~jmerck/GEOL388/lectures/03.html&h=480&w=314&sz=111&hl=en&start=19&tbnid=-oyidtyoCwaOVM:&tbnh=129&tbnw=84&prev=/images%3Fq%3Dtuff%2Brocks%26gbv%3D2%26hl%3Den


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6ie2 of agg$'era#e

Agg$'era#eand tuff


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Tu,, - #e !rregu$ar$G "a5ed g$a"" "ard" are "#!$$re$a#!9e$G u%de,r'ed4 A$" %#e #e rG"#" ,=uar#8 ($ear) a%d !#!#e (dar red) !% #!" "$!de4V!e !" u%der V!e !" u%der 5$a%e 5$ar!8ed $!g#4Sa'5$e !" ,r' Ne9ada4

Ke$ded rG$!#! #u,, - #e g$a"" "ard" are ,u"ed#ge#er !% a "!r$G 'a""& a%d #e $arge 5u'!e,rag'e%# a# e%#er r!g# !" ,$a##e%ed4 I% %#ra"#&=uar#8 rG"#" are re$a#!9e$G u%de,r'ed4 V!e !"u%der 5$a%e 5$ar!8ed $!g#4 Sa'5$e !" ,r'

Ne9ada4

Tufo Tufo "ol&a&o


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&

F!a''e are 5u'!e a%d g$a"" #a# a9e $$a5"ed a%d '5a#ed4F!a''e ,#e% d!"5$aG ,$a'e "#ru#ure" (#!% , ,$a'e" !% a ,!re)4 Tee$%ga#ed !#e 'a"" !% #e e%#er !" ,!a''e4 I# "" ,$a'e

"#ru#ure" % #e $e,# a%d a$%g #e ##'4 N#e #e ,$a##e%ed g$a"""ard" dra5!%g 9er '!%era$"4


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!+H/;? Tufo mo"tran&o fragmento" ltico" e cri"tai" %-uartzo e fel&"pato' em partcula" &ei&ro fino %cinza'. O("erar a -uanti&a&e &e "#ar&" forman&o ,rea" clara" . 5 277


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!+H/;? Tufo mo"tran&o cla"to" ltico" e cri"tai" em partcula" &e i&ro fino%cinza'. 8*;? 2


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!+H/58 Tufo mo"tran&o fragmenta&o" em matriz &e cinza. 5 2


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