Chemical composition and classification of the Caçapava do Sul
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Brazilian Journal of Development 10144
ISSN: 2525-8761
Chemical composition and classification of the Caçapava do Sul
Meteorite
Composição química e classificação do meteorito de Caçapava do Sul
DOI:10.34117/bjdv7n1-687
Recebimento dos originais: 10/12/2020
Aceitação para publicação: 26/01/2021
Daniele Martins Soares
Bacharela em Geologia pela Universidade Federal do Pampa
Endereço: Rua Santa Catarina, n° 3528, Zona II, Umuarama-PR
E-mail: danielems26@gmail.com
Leonardo Santos Souza
Graduado em Licenciatura em Ciências Exatas pela Universidade Federal do Pampa
Endereço: Rua Riachuelo, n° 815, Centro, Caçapava do Sul-RS
E-mail: leonardosantosouza26@gmail.com
Deini Werb
Graduando em Geologia pela Universidade Federal do Pampa
Endereço: Rua Arnoldo Osvaldo Mentz, n° 433, Vila Nova, Igrejinha-RS
E-mail: deiniwerb@hotmail.com
Vinicius de Abreu Oliveira
Prof. Dr. na Univerisade Federal do Pampa
Endereço: Prédio do LATRAM – sala 206Av. Pedro Anunciação, nº 111 - Vila Batista,
Caçapava do Sul – RS, Brazil
E-mail: viniciusoliveira@unipampa.edu.br
ABSTRACT
The amount of material present in the interplanetary space of the Solar System is still not
completely known, as well as its size. Incidentally, they can be as small as grains of dust
to bodies larger than 100 m in diameter. Meteoroids are a kind of these materials present
in the interplanetary space are meteoroids. These are the bodies that penetrated the
atmosphere reaching the Earth's surface, in this case, they are renaming like meteorite.
They are similar ages to the origin of the Solar System, presenting geological
characteristics similar to the known rocky planets. In fact, they can be an indirect means
to extract information regarding the origin of the Solar System and the Earth. At the
beginning of March 2017, a 26 cm wide and 27-kilo rock fallen in the early twentieth
century, was confirmed as a meteorite. It receives the name of Caçapava do Sul Meteorite
referring to the homonymous city. The meteorite was donated to the Universidade Federal
do Pampa (UNIPAMPA), Campus Caçapava do Sul, Brazil, by the son of the person who
finds the rock. This donation enabled the beginning of studies aimed at determining its
chemical composition and its classification. This work is justified by the importance of
understanding meteorites, as they keep records of the composition of the celestial bodies
that make up the Solar System. Therefore, this work aims to classify the Caçapava do Sul
Meteorite through geochemistry and determining its composition. And as a secondary, its
classification according to the weather. Samples of the meteorite were sent to Prof. Dr.
Brazilian Journal of Development, Curitiba, v.7, n.1, p. 10144-10151 jan. 2021
Brazilian Journal of Development 10145
ISSN: 2525-8761
Maria Elizabeth Zucolotto, curator of meteorology at the Museu Nacional - RJ, Brazil,
for a preliminary analysis of the rock. Prof. Dr. Zucolotto sent these preliminary analysis
data to the Laboratory for Space Geosciences and Astrophysics (LaGEA). In possession
of the data from the geochemical analysis, a bibliographic survey of the possible
classifications that can be carried out based on geochemical analyzes regarding meteorites
was carried out. After the analysis, it was possible to verify that the studied rock is a
meteorite, due to the chemical and macroscopic characteristics presented. Because it has
high amounts of Iron and Nickel elements, the meteorite is classified as siderite, and
structurally, the meteorite was classified as an octahedrite. Then, it is possible to classify
the Caçapava do Sul Meteorite as being octahedrite siderite. However, more studies are
needed for a better geochemical characterization of the same. A search of the recovery
site, even after more than 100 years may also bring some new information to this story.
Keywords: Caçapava do Sul Meteorite, Chemical composition, Classification.
RESUMO
A quantidade de material presente no espaço interplanetário do Sistema Solar ainda não
é completamente conhecida, assim como a sua dimensão. A propósito, podem ser tão
pequenos como grãos de pó para corpos com mais de 100 m de diâmetro. Os meteoróides
são uma espécie destes materiais presentes no espaço interplanetário são meteoróides.
Estes são os corpos que penetraram na atmosfera atingindo a superfície da Terra, neste
caso, estão a renomear como meteorito. São idades semelhantes à origem do Sistema
Solar, apresentando características geológicas semelhantes às dos planetas rochosos
conhecidos. De facto, podem ser um meio indirecto para extrair informação sobre a
origem do Sistema Solar e da Terra. No início de Março de 2017, uma rocha de 26 cm de
largura e 27 quilos caída no início do século XX, foi confirmada como um meteorito.
Recebe o nome de Meteorito de Caçapava do Sul, referindo-se à cidade homónima. O
meteorito foi doado à Universidade Federal do Pampa (UNIPAMPA), Campus de
Caçapava do Sul, Brasil, pelo filho da pessoa que encontra a rocha. Esta doação permitiu
o início dos estudos destinados a determinar a sua composição química e a sua
classificação. Este trabalho justifica-se pela importância de compreender os meteoritos,
uma vez que estes mantêm registos da composição dos corpos celestes que compõem o
Sistema Solar. Por conseguinte, este trabalho visa classificar o Meteorito de Caçapava do
Sul através da geoquímica e determinar a sua composição. E, como secundário, a sua
classificação de acordo com o tempo. Foram enviadas amostras do meteorito à Prof. Dra.
Maria Elizabeth Zucolotto, curadora de meteorologia no Museu Nacional - RJ, Brasil,
para uma análise preliminar da rocha. A Prof. Dra. Zucolotto enviou estes dados
preliminares de análise ao Laboratório de Geociências Espaciais e Astrofísica (LaGEA).
Na posse dos dados da análise geoquímica, foi realizado um levantamento bibliográfico
das possíveis classificações que podem ser realizadas com base em análises geoquímicas
relativas a meteoritos. Após a análise, foi possível verificar que a rocha estudada é um
meteorito, devido às características químicas e macroscópicas apresentadas. Uma vez que
possui elevadas quantidades de elementos de Ferro e Níquel, o meteorito é classificado
como siderite, e estruturalmente, o meteorito foi classificado como octahedrite. Depois,
é possível classificar o meteorito de Caçapava do Sul como sendo octahedrite siderite. No
entanto, são necessários mais estudos para uma melhor caracterização geoquímica do
mesmo. Uma pesquisa do local de recuperação, mesmo após mais de 100 anos, pode
também trazer alguma informação nova a esta história.
Palavras-chave: Meteorito de Caçapava do Sul, Composição química, Classificação.
Brazilian Journal of Development, Curitiba, v.7, n.1, p. 10144-10151 jan. 2021Brazilian Journal of Development 10146
ISSN: 2525-8761
1 INTRODUCTION
The amount of material present in the interplanetary space of the Solar System is
still not completely known, as well as its dimension. Indeed, they can be as small as grains
of dust up to bodies larger than 100 m in diameter. Speaking of that, this dimension is
used as a marker of a nominal separation, i.e, those rocky objects without ice with
diameters smaller than 100 m are classified as meteoroids, the largest being asteroids
(ACEVEDO et. Al, 2014). The authors still classify rocky rocks with ice as comets.
According to Zucolotto et al. (2013), meteoroid is a generic name for rock bodies
smaller than 100 m in diameter in the interplanetary space. It is named meteor when they
penetrate the Earth's atmosphere. Whether it survive the burning as a meteor and reach
the surface, with the possibility of recovering it, we can renamed its like meteorite. The
arrival of a meteorite is announced by the passing of a bolide, accompanied by sound
effects (explosions) and visuals.
Meteorites are ancient objects, dating back to the origin of the Solar System (about
4.6 billion years), thus presenting geological characteristics common to all known rocky
planets. The importance of the study of meteorites lies mainly in this fact because it is
possible to verify in loco materials of the formation of the Solar System without the action
of the common weathering to the planets. At the same time, it is possible to analyze a
geological evolution in extremely low gravity and temperature, and yet, according to
Piani et al. (2020) meteorites can bring information on how water appeared on planet
Earth.
As there are several types of meteorites, a classification based in concentrations
of iron and silicon has been created. According to Oliveira (2015) and Zucolotto et al.
(2013) it is possible to divide meteorites into:
siderites (metallic) composed of metallic alloy of iron and nickel;
rocks formed by silicates, which can be subdivided into chondrites and
achondrites;
siderolites (mixed) consisting of a mixture of iron-nickel and silicates in
equivalent proportions.
Annually, there are meteoroids reach the surface of the Earth in the form of
meteorites of all sizes. Zucolotto et al. (2013) point out that this amount is approximately
five hundred a year, but about two-thirds of these fall into the water, which makes
recovery impossible. Among those who fall to the ground, only four or five are recovered.
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ISSN: 2525-8761
In Winter et al. (2007), the authors estimate that more than a ton of material reaches the
Earth's atmosphere daily, with most disintegrating completely before reaching the
ground.
It is important to make it clear that these statistics are falls and not recovery.
According to Acevedo et. al (2014) the amount of meteorites recovered in South America
represents about 1% of the world total. They suggest that due to the large part of the
continent's surface being covered by tropical forest, in addition to having a humid climate
that makes it difficult to recover larger objects and, consequently, most wanted. The
authors point out that the Atacama Desert represents 70% of the total objects collected in
the entire South American subcontinent, precisely because it does not have such
characteristics.
In face of, locating a meteorite from which information can be extracted for
studies on the origin of the Solar System, and the Earth, is sometimes a difficult task.
Even more considering the cases of false meteorites, which would rock exotic to the found
location but not of proven spatial origin, possibly having been taken by some external
agent. In general, these exotic rocks attract attention due to the apparent lack of belonging
to the site.
For a long time, this was the question about a rock found more than 100 years ago
on a farm in the Seival region, belonging to the municipality of Caçapava do Sul, Rio
Grande do Sul, Brazil, by a local resident. The question remained open until March 2017
when it was confirmed to be a meteorite, which was 26 cm wide and 27 kilos, having
been named Meteorite Caçapava do Sul.
Also in 2017, the meteorite was donated to the Universidade Federal do Pampa
(UNIPAMPA), Campus Caçapava do Sul, by the son of the person who finds the rock in
the early 20th century. Then, the Laboratory of Space Geosciences and Astrophysics
(LaGEA) started studies to determine the chemical composition and classification of the
Caçapava do Sul Meteorite.
2 JUSTIFICATION
The performance of this work is justified by the importance of understanding
meteorites. Since they keep records of the composition of the celestial bodies that make
up the Solar System. It is possible to verify the geological evolution of the formation of
the entire system and, in particular, of the rocky planets.
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ISSN: 2525-8761
3 OBJECTIVES
The main objective of this work is to classify the Caçapava do Sul Meteorite
through geochemistry. As a secondary, we determined the composition of the meteorite
and its classification by the geochemistry analyses.
4 METHODOLOGY
The LaGEA/UNIPAMPA provided a sample of the rock identified as Meteorite
Caçapava do Sul to the Department of Geology and Paleontology of the Museu Nacional
in 2017, under the care of Prof. Dr. Maria Elizabeth Zucolotto of the Universidade Federal
do Rio de Janeiro (UFRJ) for analysis preliminary rock. The sample was removed using
a water-cooled circular saw with a minimum of loss, resulting in two objects with an
approximately circular base of 15 cm in diameter and 300 g each.
In this way, a preliminary geochemical analysis was carried out, whose data were
made available by private e-mail from Professor Zucolotto to LaGEA/UNIPAMPA.
Based on these geochemical data from the Meteorite Caçapava do Sul, a
qualitative analysis was carried out. At the same time, a bibliographic survey was carried
out on meteorites already cataloged in Brazil and on meteorological classification.
5 RESULTS and DISCUSSION
To perform a classification of the Meteorite Caçapava do Sul it was necessary to
identify its geochemical composition. Thus, the table below presents the results of the
geochemical analysis sent to LaGEA / UNIPAMPA by Prof. Dr. Maria Elizabeth
Zucolotto.
Table 1: Geochemical analysis of the Caçapava do Sul meteorite, in percentage relative to the sample
mass.
Sample Number P Fe Cr Ni Co Si Total
1 0.00 92.0 0.00 7.20 0.70 0.01 99.9
2 0.01 91.9 0.02 7.37 0.63 0.01 100
3 0.00 91.9 0.01 7.31 0.66 0.02 99.9
4 0.02 92.2 0.02 7.30 0.68 0.01 100
5 0.00 91.5 0.00 7.42 0.59 0.01 99.5
6 0.00 79.1 0.00 20.2 0.37 0.01 99.7
7 0.02 80.7 0.01 19.2 0.41 0.02 100
8 0.01 78.5 0.00 21.5 0.35 0.01 100
9 0.02 78.3 0.00 22.0 0.31 0.03 101
10 0.02 77.1 0.01 22.9 0.33 0.02 100
Minimum 0.00 77.1 0.00 7.20 0.31 0.01
Mean 0.01 85.3 0.01 14.2 0.50 0.02
Std. Dev. 0.01 7.00 0.01 7.36 0.16 0.01
Maximum 0.02 92.2 0.02 22.9 0.70 0.03
Source: provided by Prof. Dr. Maria Elizabeth Zucolotto in a private e-mail.
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ISSN: 2525-8761
The values represented in Table 1 represent fractions from a single sample that
were measured at different points. This sample was taken from the study material to
perform an analysis of the spatial distribution of the measured elements, resulting in the
corresponding levels of each element that is present in the rock. Although Table 1
indicates the chemical abundance values of a single sample, it is very likely that these
results are proportional to the values that would be found for the entire meteorite due to
the homogeneity present in objects of this type.
The main results inferred from Table 1 indicate an average of the chemical
elements Iron (Fe) and Nickel (Ni) composing about 99.5% of the rock. At the same time,
it is noted that the values of silica (Si) do not exceed 1% of the total. These results indicate
that it is a meteorite because according to Grotzinger and Jordan (2013) the rocks of the
earth's crust and mantle have values above 40% of silica, and smaller amounts of iron and
nickel than found in the analyzed sample.
These characteristics, associated with the macroscopic properties of the rock,
highlighted in Figure 1, are indications that maintain that this rock was not formed on
planet Earth, being, therefore, a meteorite. That is, it is observed:
high density;
grooves and depressions (regmalites) on its surface;
silver internar color.
Figure 1: Caçapava do Sul Meteorite (scale used: coin of ten cents of Real), the rust process stands out in
the recently exposed section.
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Currently, in Brazil, there are 77 meteorites recovered and officially recognized.
The Meteorite Caçapava do Sul is in the process of recognition, it will probably be the
78th. Using only a structural classification, that is, what can be seen with the naked eye,
among the 77 meteorites recognized in Brazil, 39% are rocky (mostly chondrites). Among
the metallic ones, octahedrite is the most common (21 meteorites among 27). Octaedrites
are those metallic meteorites that when attacked with nitric acid have intertwined lines
that become evident to the naked eye, this is known as the Widmanstätten Pattern (Figure
2).
Figure 2: Cut the sample of Caçapava do Sul Meteorite right after the nitric acid attack to highlight the
Widmanstätten Pattern
6 FINAL CONSIDERATIONS
After geochemical analysis, it is possible to indicate that the studied rock is a
meteorite. This statement is supported when considering the chemical and macroscopic
structural characteristics of the object. Since its outer surface has a large number of
regmalites suggesting a large melting edge. This effect occurs during passage through the
Earth's atmosphere at high speed.
Thus, due to its high amounts of elements Iron (85.3%) and Nickel (14.2%), the
meteorite is classified as siderite. Since it contains approximately 15% Nickel in its
composition and has a Widmanstätten structure, the siderite meteorite is structurally
classified as an octahedrite.
Finally, the complete classification of the Meteorite Caçapava do Sul is
octahedrite siderite. However, more geochemical studies are necessary for a deeper
understanding of the history of this meteorite when still in orbit in the Solar System. A
search of the recovery site, even after more than 100 years may also bring some new
information to this story.
Brazilian Journal of Development, Curitiba, v.7, n.1, p. 10144-10151 jan. 2021Brazilian Journal of Development 10151
ISSN: 2525-8761
REFERENCES
ACEVEDO, R.D.; ROCCA, M.C.L.; GARCÍA, V.M. Catalogue of Meteorites from
South America. Buenos Aires: Springer, 2014.
GROTZINGER, J.; JORDAN, T.; Para entender a Terra. 6. ed. Porto Alegre: Bookman,
2013.
OLIVEIRA, I. M. Meteorítica: Introdução à meteorítica e uma visão geral dos meteoritos
brasileiros. 1. ed. Rio de Janeiro, 2015.
PIANI, L.; MARROCCHI, Y.; RIGAUDIER, T.; VACHER, L.G.; THOMASSIN, D.;
MARTY, B. Earth’s water may have been inherited from material similar to enstatite
chondrite meteorites, Science, v. 369, 2020.
WINTER, O. C.; PRADO, A. F. B. A. (Org.) . A Conquista do Espaço - do Sputnik à
Missão Centenário. 1. ed. São Paulo: Editora Livraria da Física, 2007. v. 1. 320p .
ZUCOLOTTO, M. E.; FONSECA, A. C.; ANTONELLO, L. L. Decifrando os
Meteoritos. Museu Nacional - Universidade Federal do Rio de Janeiro. Rio de Janeiro,
2013.
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