Provenance discrimination between Atasta and Alvarado beach sands, western Gulf of Mexico, Mexico: Constraints from detrital zircon chemistry and U–Pb geochronology

The bulk sand samples and detrital zircons collected from the Atasta and Alvarado beach areas in the southwestern Gulf of Mexico have been analysed for geochemistry and U–Pb ages to constrain their provenance. The index of chemical maturity and SiO2/Al2O3 ratio of the Atasta and Alvarado beach sands...

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Bibliographic Details
Published in:Geological journal (Chichester, England) England), 2018-11, Vol.53 (6), p.2824-2848
Main Authors: Armstrong‐Altrin, John S., Ramos‐Vázquez, Mayla A., Zavala‐León, Ana C., Montiel‐García, Patricia C., Tyrrell, S.
Format: Article
Language:English
Subjects:
Age composition
Aluminum oxide
Anomalies
beach sands
Beaches
Cenozoic
Clusters
Earth
Geochemistry
Geochronology
Geochronometry
Geological time
heavy mineral
Igneous rocks
Lead
Magma
Mesozoic
Organic chemistry
Palaeozoic
Precambrian
Provenance
Radiometric dating
rare earth element
Rare earth elements
Sand
Silica
Silicon dioxide
Volcanic belts
Zircon
zircon age
zircon chemistry
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Summary:The bulk sand samples and detrital zircons collected from the Atasta and Alvarado beach areas in the southwestern Gulf of Mexico have been analysed for geochemistry and U–Pb ages to constrain their provenance. The index of chemical maturity and SiO2/Al2O3 ratio of the Atasta and Alvarado beach sands indicated low compositional maturity. The chondrite‐normalized REE patterns and Eu anomalies of the Atasta and Alvarado beach sands suggested that the sands were derived from felsic and intermediate igneous rock types, respectively. A wide range in Th and U contents of the Atasta (~1.0–884 ppm and ~39–883 ppm, respectively) and Alvarado (~13–2,641 ppm and ~21–2,457 ppm, respectively) zircons likely indicates that the detrital zircon populations consist of zircons derived from multiple sources. The total rare earth element (ΣREE) content in the Atasta and Alvarado zircons ranges from ~151 to 2,088 ppm and ~154 to 3,580 ppm, respectively. The chondrite‐normalized REE patterns of zircons from the two beach areas show slightly depleted light REE (LREE) and enriched heavy REE (HREE), as well as positive Ce and negative Eu anomalies. A few zircons of Alvarado beach lack a Ce positive anomaly but exhibit a distinct Eu anomaly. The differences in REE patterns among zircons between the two beach areas revealed the variations in the type of source terranes, which supplied zircons to the beach areas. The detrital zircon age distribution for the Atasta beach is homogeneous, showing a prominent Proterozoic peak (~596–2,461 Ma; number of samples n = 62) with few Cenozoic (~10.43–65.2 Ma; n = 4) and Palaeozoic (~380–468 Ma; n = 5) zircons. The zircon U–Pb ages of Alvarado beach revealed Cenozoic (~0.25–63.9 Ma; n = 65), Mesozoic (~67.9–181.2 Ma), Palaeozoic (~252–297 Ma), and Proterozoic (~589–1,501 Ma) age clusters with predominant Cenozoic zircons. The comparison of zircon REE chemistry and geochronological data of this study with published data suggests that the source terranes, which supplied zircons to the Atasta beach, were the Chiapas Massif and Oaxacan complexes, whereas the zircons in the Alvarado beach were derived from the nearby Mexican Volcanic Belt and Eastern Alkaline Province. The provenance variation between the two beach areas was also revealed by the dissimilarities in zircon age clusters.
ISSN:0072-1050
1099-1034
DOI:10.1002/gj.3122