Characterization of heavy minerals and luminescence of quartz from sands of the Branco River in the region of Boa Vista (Roraima)

• Grant number: 11/05897-3
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2011
• End date: August 31, 2012
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geology
• Principal Investigator: André Oliveira Sawakuchi
• Grantee: Lina Akiko Araki
• Host Institution: Instituto de Geociências (IGC). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The Branco river is the major tributary of the Negro river, Amazon river basin. It drains the Roraima State in the northern Amazon rainforest. The Branco River between Boa Vista city and Grande hill (about 40 km downstream) stands out due to its huge sand bedload, allowing the development of many sandy depositional elements, such as point bars, longitudinal bars and sand waves. We suppose that the Branco river is an important source of sandy sediments to the Negro river and consequently to the Amazon River. The provenance and degree of sedimentary reworking of the Branco river sands are important to understand the sediment transport within the Amazon rivers. The objective of this project is to characterize the heavy minerals and quartz luminescence within the Branco river sands. These data aim to determine the source rocks and degree of sedimentary reworking of the Branco river sands. The heavy minerals and luminescence analysis will be carried out in samples collected in the main channel of the Branco river between Boa Vista and Grande hill. Heavy mineral analysis will comprise the identification of heavy mineral types and measurements of heavy mineral indexes (RZi and ZTi). Luminescence analysis will focus on measurements of the thermoluminescence sensitivity of quartz. Variations in heavy mineral types and indexes and in the thermoluminescence of quartz will be compared to lithology, geomorphologic and vegetation characteristics of the studied area. The development of this project will allow the undergraduate student to be trained in heavy mineral and luminescence methods applied to provenance analysis and the study of fluvial depositional systems. This Scientific Initiation project will integrate the research project "Provenacne, transport and storage of sediment in the Amazon rivers" (process:2011/06609-1), which has the participation of graduate students and researchers of geosciences institutions from Brazil, United States of America and Germany. Thus, the applicant Lina Akiko Araki will participate of activities carried out in a multidisciplinary research group, providing great scientific and cultural learning.