LABISE: Foundation and 25 years of activities

Alcides N. Sial was introduced to low- and high-temperature stable isotope

geochemistry by Prof. Lynton Land during post-doctoral work in the Department

of Geological Sciences of the University of Texas (UT), at Austin (1977‒1978).

He learned about oxygen gas extraction from silicates using a conventional,

high-vacuum extraction line having bromine Br2F5 as main reagent, besides

hydrogen gas extraction and how to run an old-fashioned Nuclide gas-source

mass spectrometer.

The positive experience at UT encouraged Sial to broaden his background

on stable isotope geochemistry and to visit other stable-isotope laboratories in

USA. With this purpose, he spent the entire year of 1983 in the University of

Georgia at Athens, where he was exposed to multiple applications of stable

isotopes and related laboratorial techniques. In the same year, he spent two

months at the Department of Geology of the Memorial University of

Newfoundland, learning the analytical method for rare-earth element analysis

by X-ray fluorescence from Prof. Brian Fryer.

The challenging complexity of granites, their metallogeny and importance

in reconstruction of geotectonic setting, have stimulated A.N. Sial to found the

Nucleus for Granite Studies (NEG) in the Department of Geology of the UFPE on

February 1984. Since then, the NEG has developed petrological, geochemical

and isotopic studies on granitic rocks of northeastern Brazil, Argentina, Chile,

Uruguay and India, mainly on igneous processes and investigation of the source

of granitic magmas. The name of this Nucleus was changed to Nucleus for

Geochemical Studies in 1995, preserving the NEG acronym.

In 1988, two conventional high-vacuum extraction lines (carbonate and

silicate) were built with the help of David Wenner and Andrew Clarke while A.N.

Sial was in post-doctoral work and V.P. Ferreira a Ph.D. student in the

University of Georgia at Athens. In that year, they spent the entire month of

August in the Geological Survey of Japan at Tsukuba, learning from Prof. Akira

Sasaki, the technique of extraction of sulfur from igneous rocks using the Kiba

solution and gas-source mass spectrometry for sulfur isotopes. The scientific

Figure 1. The Stable isotope Laboratory (LABISE) of the Department of Geology, Federal University of Pernambuco, founded in 1990.

experience acquired from all these stable-isotope laboratories in USA and Japan

led A.N. Sial to found, with financial support of the PADCT (Program of Support

to Scientific and Technological Development, financed by the World Bank), a

stable isotope laboratory (LABISE) in the Federal University of Pernambuco,

pioneering in Brazil the analysis of oxygen isotopes from silicates, in September

1990. In this endeavor, the Department of Geology had the sympathy from the

Rector, Prof. Edinaldo Bastos, who built the physical space to accommodate this

laboratory, comprising two high-vacuum extraction lines (Fig. 1a) and a stable

isotope ratio analyzer mass spectrometer (SIRA II) (Fig. 1b) besides office

space for faculty members. The high-vacuum extraction lines (carbonate and

silicate) were built in the workshop of the University of Georgia at Athens and

transferred to Recife where they were reassembled by A. N. Sial, G. Mariano

and V.P. Ferreira. Prof. Efrem Maranhão, who replaced Prof. Edinaldo Bastos,

and Prof. Mozart Neves Ramos, financially supported the expansion of the

physical space of the LABISE to accommodate an X-ray fluorescence laboratory

(Rigaku-3000) in 1994 and a sample preparation room in 1996.

Figure 2. (a) Conventional high-vacuum extraction lines for carbonate and (b) conventional line for silicate (fluorine line). (c) Stable isotope ratio analyzer mass spectrometer (SIRA II).

In 1996, A. N. Sial and V.P. Ferreira spent couple of weeks in East

Kilbride, Scotland, visiting with Prof. Anthony E. Fallick the analytical facilities of

the Scottish Universities Research and Reactor Centre (SURRC) one of the most

complete set of stable-isotope laboratories in Europe. They also visited with

Prof. John Valley the Department of Geology and Geophysics of the University

of Wisconsin, at Madison in 2001, learning on CO2 laser-based high vacuum

extraction lines for silicates. Upon their return, the LABISE underwent its latest

physical expansion to accommodate an ion-exchange laboratory (clean station),

a CO2 laser-based oxygen extraction line from silicates and oxides (built by

Zachary Sharp, University of New Mexico), and an elemental combustion

system (COSTECH) for carbon and nitrogen analyses, on-line with a

Thermofinigan Delta V Advantage gas-source mass spectrometer and more

recently, a GasBench II to go along this spectrometer.

Sial and Ferreira are igneous petrologists (basalts, mantle petrology,

granites) since they were hired by UFPE (A.N. Sial, March 1967, and V.P.

Ferreira, August 1989), but versatility, enthusiasm and curiosity have led them

to other venues, as isotope stratigraphy. From 1986 to 1994, the NEG‒LABISE

counted with the participation of Gorki Mariano who had been also trained in

the University of Georgia and helped in the first stages of installation of the

stable isotope laboratory besides the running of a fluorine high-vacuum

extraction line. The NEG-LABISE has kept close scientific cooperation on granite

studies and isotope stratigraphy with researchers from Brazil, Argentina, Chile,

Uruguay, Colombia, Mexico, Portugal, India and United States.

Figure 3. (a) CO2 laser-based oxygen extraction line from silicates and oxides; (b) GasBench II and an elemental combustion system (COSTECH) for carbon and nitrogen analyses on-line with a Thermofinigan Delta V Advantage gas-source mass spectrometer; (c) Clean station.

Figure 4. (a) Rigaku-3000 XRF unit; (b) Sample preparation room.

In 1985, the NEG organized a workshop on Granitic Magmatism and

Associated Mineralizations at Caruaru, Pernambuco, gathering about 15

enthusiastic young Brazilian granitologists. A field trip in northeastern Brazil to

the Cachoeirinha‒Salgueiro Belt helped bringing their attention to granitoids of

uncommon diversity and evolution. The same group of granitologists gathered

again in 1987 at Salvador, Bahia, in the International Symposium on Granites

and Associated Mineralizations (ISGAM) and in 1997 in a second edition of the

ISGAM, all of these Meetings organized by the NEG‒LABISE. Besides the ISGAM

series, other international Meetings were organized, on two themes: Granitic

Magma and Associated Mineralizations (MAGMA) within the frame of the

International Geological Congress (31st, 32nd and 33rd IGC) or Brazilian Academy

of Science (Rio, 1993), and on isotope geology (4th South American Symposium

on Isotope Geology = SSAGI, 2003). Since 1992, the NEG-LABISE has annually

organized a Meeting of the Brazilian Academy of Sciences at Recife, and a short

course (75 hours/class) on stable and radiogenic isotopes and their multiple

applications, with participants from all over the country. The NEG-LABISE has

attempted to disseminate granite petrology and high and low-temperature

geochemistry of stable isotopes by teaching short courses in several universities

in Brazil, including UFRGS, UFRJ, UFPA, UFPE, UFMG, UFMT, University of Chile

(Santiago, 2003), Latin-American Congress (Medellin, 2011) and in several

Brazilian Meetings.

Figure 5. Some participants of the “Stable and Radiogenic Isotopes” course in August 2015.

The study of Neoproterozoic magmatic epidote-bearing granitoids in

northeastern Brazil, Paleozoic in Argentina and Tertiary in Chile, represents

perhaps one of highlight contributions from the NEG‒LABISE to the granite-

petrology field in papers published in international journals (1999, 2003, 2008,

2011, 2015). In these papers it was proposed that partial digestion of magmatic

epidote by its calc-alkaline or high- K calc alkaline host magma could be used to

estimate speed of host magma ascent.

From 1995 on, the NEG-LABISE scientific interest was broadened to

include isotope chemostratigraphy and from then on, a continuous and fruitful

Figure 6. Pie-chart giving an idea of amount of publications emerged from the NEG-LABISE (1984-2015).

cooperation with colleagues from Argentina (Silvio Peralta, Gilberto Florencio

Aceñolaza, R. Narcizo Alonso and Alejandro J. Toselli), Uruguay (Claudio

Gaucher and Jorge Bossi) and Chile (Miguel Angel Parada). This group has

documented by the first time in South America the isotope record of the

Steptoean positive isotope carbon excursion (SPICE) and recognized by the first

time the Sunwaptan negative carbon isotope excursion (SNICE) in the

Argentine Precordillera. Moreover, they recognized by the first time in South

America the record of the Ordovician MDICE, GICE and HICE positive carbon

isotope excursions. Anil Maheswari, A.N. Sial, Claudio Gaucher, Andrey Bekker,

Valderez P. Ferreira, Jorge Bossi and Wilson Romano have contrasted the

record of the Paleoproterozoic Lomagundi excursion in India, Brazil and

Uruguay. They found that this excursion is recorded in both shallow-water and

deep-water carbonates negating a significant impact of stromatolite productivity

and hypersaline conditions on carbon isotope values of carbonates deposited in

shallow-water, open-marine and isolated basins.

Figure 7. Analytical support given by the LABISE to several institutions since its foundation in 1990.

Annually, the LABISE through the Post-graduation in Geology, offers two

courses on Chemostratigraphy (45 hour classes), one devoted to the

Precambrian and the other one, to the Phanerozoic. Based on these two

courses, the LABISE was responsible to prepare the Chapter 2 of a recent book

published by Elsevier on Elemental and Isotope Chemostratigraphy (M.

Ramkumar, ed.: Chemostratigraphy, Concepts, Techniques and Applications.

Elsevier, pp. 23–64. http://dx.doi.org/10.1016/B978-0-12-419968-2.00002-9,

ISBN 9780124199682).

In the last five years, the research in the NEG‒LABISE was turned to the

possible use of Hg as a tracer of volcanism during events of extreme climatic

changes. At present, it is being built a database with Hg analyses (supposedly

of volcanic origin) from Cryogenian‒Ediacaran cap carbonates and from

carbonates across the Cretaceous‒Paleogene boundary of several localities

(Europe, South America and India). The intent is to evaluate the extension of

participation of volcanism versus bolide impact on the mass extinction of the

K‒T boundary. A new project focusing the Permian‒Triassic boundary is under

way.

The contagious enthusiasm of the NEG‒LABISE team for science has

attracted young geologists for graduate studies (over fifty students have been

supervised/co-supervised in Master´s or doctoral-degree work or both or

traineeship), post-doctoral work, or long or short-term visit of geoscientists

(Anil Maheswari, Manoj K. Pandit, Lalchand Govindram Gwalani, Vinod C.

Tewari from India; Ignacio Sabino Garcia and Lucia Peral Gomez, from

Argentina; Jean Pierre Tchouankoue, from Cameroon, Marcelo Solari, from

Chile; Pedro Morais from Portugal, besides several Brazilian researchers). Over

two hundred scientific papers (most of them in international journals), about 20

book chapters, 3 books and 12 special issues, most of international Journals

(Lithos, Chemical Geology, Precambrian Research, Gondwana Research, Journal

of South American Earth Sciences, Annals of the Brazilian Academy of Science,

Revista Brasileira de Geociências) have emerged from the NEG‒LABISE team.

On its 25th anniversary, the LABISE aims at significant contribution to the

development of stable-isotope geology in South America and with this purpose

will lend analytical support to scientific projects in several countries of this

continent as well as to thesis/dissertations all over Brazil.