Combination of analytic techniques to chemical characterization and preservation of Jurassic clam shrimp carapaces from La Matilde Formation, Patagonia

Author(s)

Jimenez, Victoria C. ^{[1, 2]} ; Monferran, Mateo D. ^{[1, 2]} ; Speranca, Marco A. ^[3] ; Castro, Jeyne P. ^[3] ; Catelani, Tiago A. ^[3] ; Pellerano, Roberto G. ^[4] ; Perino, Ernesto ^[5] ; Pereira-Filho, Edenir R. ^[3] ; Cabaleri, Nora G. ^[6] ; Gallego, Oscar F. ^{[1, 2]}

Affiliation

^[1] Univ Nacl Nordeste, Ctr Ecol Aplicada Litoral CECOAL CONICET UNNE, RA-3400 Corrientes - Argentina

^[2] Univ Nacl Nordeste, Dept Biol, FaCENA, RA-3400 Corrientes - Argentina

^[3] Univ Fed Sao Carlos, Dept Chem, BR-13565905 Sao Paulo - Brazil

^[4] Univ Nacl Nordeste, Inst Quim Basica & Aplicada Nordeste Argentino IQ, FaCENA, RA-3400 Corrientes - Argentina

^[5] Univ Nacl San Luis, Inst Quim San Luis CONICET, Area Quim Analit, BWS, Chacabuco & Pedernera, D5700, San Luis - Argentina

^[6] Univ Buenos Aires, Inst Geocronol & Geol Isotop INGEIS CONICET, Ciudad Univ, C1428EHA, Buenos Aires, DF - Argentina

• Document type: Journal article
• Source: Journal of South American Earth Sciences; v. 109, AUG 2021.
• Web of Science Citations: 0

Abstract

Chemical studies of fossil clam shrimps have taken relevance in the possibility of inferring about fossilization processes. Laser-induced Breakdown Spectroscopy (LIBS) is an attractive technique for geological analyses because the laser can ablate a few micrograms directly from a small area on the solid sample. On the other hand, RAMAN spectroscopy is a technique that allows rapid and non-destructive in situ detection of the components of the samples and has been used in micropalaeontology to identify carbonaceous materials. In this study, the aim was an analysis of the preservation of the clam shrimp Eosolimnadiopsis? santacrucensis Gallego, 1994 from La Matilde Formation (Jurassic) using diverse methods including LIBS, RAMAN and X-ray fluorescence (XRF) techniques as well as surrounding rock. Afterwards LIBS results were evaluated using principal component analysis (PCA). According to XRF data, Si was the main element, indicating that the rock sample consists primarily of silicate minerals. Our results of LIBS and PCA analysis indicate chemical changes between the points from carapaces and rock matrix. Some areas of the carapace showed high peaks of Ca, Na, Mg and it was variable for Si, while in other parts of the carapace and rock matrix the Si remained at high intensity. Also, RAMAN spectroscopic analysis revealed the presence of amorphous carbon. This is the first report and evaluation on the LIBS and RAMAN techniques applied to fossil clam shrimps and contributes to obtaining a range of additional information to subsequently establish the different mechanisms involved in the taphonomic history of these organisms. (AU)

• FAPESP's process: 14/22408-4 - Use of Laser-Induced Breakdown Spectroscopy (LIBS) for direct alloys analyses
• Grantee: Jeyne Pricylla Castro Castilho
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 12/01769-3 - Development of spectroanalytical methods for direct analysis of waste electrical and electronic equipments and cosmetics
• Grantee: Edenir Rodrigues Pereira Filho
• Support Opportunities: Regular Research Grants
• FAPESP's process: 16/17221-8 - Composition evaluation of hard discs from electronic waste using spectroanalytical techniques: rare earth and noble metals determination
• Grantee: Jeyne Pricylla Castro Castilho
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 16/01513-0 - Laser-Induced Breakdown Spectroscopy (LIBS) application in the analyses of electronic waste (printed circuit boards and polymers), food and difficult preparation liquid samples
• Grantee: Edenir Rodrigues Pereira Filho
• Support Opportunities: Regular Research Grants