7/25/2019 Andrea Vaca_Poster REDU 2015

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7/25/2019 Andrea Vaca_Poster REDU 2015

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ABSTRACTBy using X-Ray Diffraction (XRD) and Electron Diffraction Scattering (EDS) techniques, we have determined the geochemical and mineral comosition of the volcanic samlese!ected "y the #otoa$i volcano%

EXPERIMENTAL SET UP

SEM ANALYSIS

&he angular shae of the roc' fragments as well as their minerals, thenone$istence of newly formed (!uvenile) magmatic material evidences ane$clusively hydrothermal e$losive origin%

&he samles rich in sulfur, were ta'en close to the volcano, while the ones

having high contents in iron, magnesium, manganese were located far away%ron aeared on samles far away from volcano "ecause most li'ely they

 were o$idied with atmosheric o$ygen and falls down as a *e() reciitateas soon as it gets denser article%

CONCLUSIONS

&he shae of the roc' fragments and minerals e$elled on the first erutiveevent in the early morning of the + ugust as well as yroclastic material oflater e!ections have "een e$clusively characteried as fragmented andangular shaed% .uvenile magma at the ro$imity of the crater can thereforecategorically "e e$cluded%&he mineral classification and also the chemical comosition of the e!ectedmaterial determined a tyical andesitic to dacitic and rarely rhyodacitic

comosition with a high a"undance of classical mineral comosition of suchroc's, "eing lagioclases, quart, "iotite, horn"lende "ut also o"sidian, yriteand some other accessory minerals%

REFERENCES/ &% &oul'eridis, #% R% rroyo, 0% #ru D12owitt, % De"ut, % 3% 3aca, 4% #um"al, *%

0ato, and E% guilera% 52ESS% Evaluation of the nitial stage of the reactivated#otoa$i 3olcano- analysis of the first e!ected fine-grained material% 6, 789:7897%;<+=

/ 5inithi%> Sectroscoy tools in nanotechnology, ;<+=

GEOCHEMICAL ANALYSIS OF THE FINE GRAINED MATERIAL EJECTED BY THE

COTOPAXI VOLCANO IN 2015

Vaca V. A.*; Moya C. **; Arroyo R. C.*; Debut A.*; Cumbal L.*; Mato F.*** ; Aguilera E.**; Cruz M.**;Toulkeridis T.*** 

* Cetro de !aociecia y !aotecolog"a# $i%ersidad de las Fuerzas Armadas E&'E# '.(. )o +,+--/0+)# &agol1u"# Ecuador 

e-mail2 adrea%acamora3gmail.com

** De4artameto de Ciecias de la Tierra y Costrucci5# $i%ersidad de las Fuerzas Armadas E&'E# '.(. )o +,+--/0+# &agol1u"# Ecuador 

e-mail2 macruz3es4e.edu.ec

*** De4artameto de &eguridad y De6esa# $i%ersidad de las Fuerzas Armadas E&'E# '.(. )o +,+--/0+# &agol1u"# Ecuador 

e-mail2 ttoulkeridis3es4e.edu.ec

XRD studies were carried out using a ?5alytical E0?@RE5 setu within a;A configuration (generator-detector) $-ray tu"e coer C +%= andX#E4ER&R detector (minimum angle ste <%<<<+F)% &o erform themeasurements shown in this wor', +< the ash owder samles were directlydeosited on otical microscoe slides% &he mineral comosition of the

samles was determined "y using the ?5-#DS data"ase%

&he SE0 insection was erformed using a &ES#5 0R6% &he fine grainedsamles were fi$ed onto SE0 stu"s using an adhesive layer and sutter-coated with gold (88%88G urity) "efore the SE0 imaging% &he chemicalanalysis was carried out "y an EDS of the "rand BRHIER model Juanta$;<<, installed in the SE0 cham"er and a detector X*lash 7+6<, reaching aresolution of +; e3

 

RESULTS

XRD ANALYSIS&he standard ;A  configuration in the XRD setu was used to analye themineral comosition of all samles% &he four samles show quite similarsectra and the analysis reveals comosition of a tyical 5a-rich northite% &heslight differences o"served in the main ea's from one samle to another aredue to the non-inhomogeneity and granularity of the samles%

Figur 1! X"r#$ %i&&r#'(i)* +XRD,

Figur 2! E-'(r)* Di&&r#'(i)* S'#((ri*g +EDS,

Figur .! T/ #/ )%r #3- r

%)i(% )* )(i'#- -i%

Figur 4! PAN#-$(i'#- E3$r#* X"r#$ %i&&r#'()3(r!

Figur 5! T/ #3- r

&i% )*() SEM (u6

Figur 7! S#3- r

')#(% i(/ g)-% 88988:

uri($

Figur ;! S'#**i*g -'(r)* 3i'r)') TESCAN MIRA .

Figur 8 ! SEM 3i'r)gr#/ +<000X, /)i*g (/ ur&#' (ru'(ur )& (/ #r(i'-

Figur 10 ! E-3*( 3#i*g #( (/ #3- 6$ '#**i*g -'(r)* 3i'r)')$ +SEM, i(/ *rg$ %iri= X"r#$'(r)3(r$ EDS

Position[°2θ](Copper(Cu))

20 30 40 50 60 70 80 90

Counts

0

2000

4000

6000

8000

 CENIZ C!"!P#I$C!"!%C&!

Figur < ! XRD '(ru3