TY - JOUR
T1 - Origin of holocene beachrock cements in northeastern Brazil
T2 - Evidence from carbon and oxygen isotopes
AU - Vieira, Marcela Marques
AU - Sial, Alcides Nóbrega
AU - De Ros, Luiz Fernando
AU - Morad, Sadoon
N1 - Funding Information:
This work is part of M.M. Vieira doctorate research carried out at the Geosciences Institute of the Federal University of Rio Grande do Sul, Porto Alegre, Brazil. Partial support for this work was provided by a scholarship granted by CAPES , an organ of the Ministry of Education. The authors thank the Stable Isotopes Laboratory (LABISE – Federal University of Pernambuco) for performing the stable isotope analyses. Thanks are extended to the Geology Department of the Federal University of Rio Grande do Norte for providing equipment and support.
Publisher Copyright:
© 2017
PY - 2017/11
Y1 - 2017/11
N2 - This study has utilized carbon and oxygen isotopic data to unravel the origin of Holocene beachrock cements of Rio Grande do Norte State coast, northeastern Brazil. The cements are exclusively constituted of Mg-calcite, with isopachous prismatic rim, equant spar, cryptocrystalline coating or pore-filling, pseudo-peloidal, radial and scalenohedral habits. The δ18OVPDB values of most (93%) of the samples range from −1.8‰ to +0.5‰, which are compatible with precipitation from marine waters. The δ13CVPDB values of these cements are +1.7 to +3.6‰ (average + 3.05‰) suggesting derivation from marine dissolved carbon. In a few cases, the Mg-calcite cement shows low δ13CVPDB (−7.3‰ and −7.8‰) and δ18OVPDB (−4.4‰ and −4.3) values, which may indicate precipitation or recrystallization of marine cements under the influence of meteoric waters.
AB - This study has utilized carbon and oxygen isotopic data to unravel the origin of Holocene beachrock cements of Rio Grande do Norte State coast, northeastern Brazil. The cements are exclusively constituted of Mg-calcite, with isopachous prismatic rim, equant spar, cryptocrystalline coating or pore-filling, pseudo-peloidal, radial and scalenohedral habits. The δ18OVPDB values of most (93%) of the samples range from −1.8‰ to +0.5‰, which are compatible with precipitation from marine waters. The δ13CVPDB values of these cements are +1.7 to +3.6‰ (average + 3.05‰) suggesting derivation from marine dissolved carbon. In a few cases, the Mg-calcite cement shows low δ13CVPDB (−7.3‰ and −7.8‰) and δ18OVPDB (−4.4‰ and −4.3) values, which may indicate precipitation or recrystallization of marine cements under the influence of meteoric waters.
KW - Beachrock
KW - Marine water
KW - Mg-calcite cement
KW - Stable isotopes
UR - http://www.scopus.com/inward/record.url?scp=85032952546&partnerID=8YFLogxK
U2 - 10.1016/j.jsames.2017.09.002
DO - 10.1016/j.jsames.2017.09.002
M3 - Article
AN - SCOPUS:85032952546
SN - 0895-9811
VL - 79
SP - 401
EP - 408
JO - Journal of South American Earth Sciences
JF - Journal of South American Earth Sciences
ER -