Translator Disclaimer
1 March 2019 Provenance of Heavy Minerals for the Quaternary Coastal Plain of Southernmost Brazil (Rio Grande do Sul State)
Julierme Justin Carassai, Ernesto Luiz Correa Lavina, Farid Chemale Junior, Tiago Jonatan Girelli
Author Affiliations +
Abstract

Carassai, J.J.; Lavina, E.L.C; Chemale, F., Jr., and Girelli, T.J., 2019. Provenance of heavy minerals for the Quaternary coastal plain of southernmost Brazil (Rio Grande do Sul State). Journal of Coastal Research, 35(2), 295–304. Coconut Creek (Florida), ISSN 0749-0208.

During the Quaternary, an extensive barrier system was developed in southern Brazil and northern Uruguay. The patterns of variation in the distribution and behavior of heavy minerals present in the aeolian and marine (upper shoreface-foreshore) facies of the four barriers formed in the Rio Grande do Sul costal plain were identified. Minerals were analyzed by scanning electron microscopy, including epidote, tourmaline, zircon, magnetite/ilmenite, polymorphs of aluminum silicates (andalusite, kyanite, and sillimanite), staurolite, rutile, amphibole, pyroxene, corundum, perovskite, chromite, garnet, apatite, monazite, xenotime, spinel, and titanite. In all of the barriers, zircon, magnetite, and ilmenite are the most important, followed by chromite, garnet, rutile, tourmaline, staurolite, and epidote. In total, heavy minerals indicate two primary sources in the coastal plain: (a) direct feeding from the rocks of Uruguay and Rio Grande do Sul Shield and Paraná Basin, drained by Rio Camaquã and Rio Jacuí; and (b) indirect feeding from rocks of the Andean province, drained by Rio Paraná and Rio La Plata estuary in northern Argentina. During low sea level, rivers flowed directly into the continental shelf, and their deposits were reworked during subsequent transgressive stages. Throughout this region, the atmospheric circulation pattern forms a NW oceanic swell, generating a longshore current with dominant northward direction. Thus, several transgressive-recessive pulses associated with Pleistocene glacial events pushed large volumes of sediments northward, giving rise to the present southern Brazil coastal plain.

©Coastal Education and Research Foundation, Inc. 2019
Julierme Justin Carassai, Ernesto Luiz Correa Lavina, Farid Chemale Junior, and Tiago Jonatan Girelli "Provenance of Heavy Minerals for the Quaternary Coastal Plain of Southernmost Brazil (Rio Grande do Sul State)," Journal of Coastal Research 35(2), 295-304, (1 March 2019). https://doi.org/10.2112/JCOASTRES-D-18-00066.1
Received: 30 April 2018; Accepted: 12 September 2018; Published: 1 March 2019
JOURNAL ARTICLE
10 PAGES


Share
SHARE
KEYWORDS
continental shelf
detrital mineral
longshore current
sand barrier
sediment transport
source to sink
RIGHTS & PERMISSIONS
Get copyright permission
Back to Top