Provenance and palaeoenvironmental significance of microtextures in quartz and zircon grains from the Paseo del Mar and
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Provenance and palaeoenvironmental significance of microtextures in quartz and zircon grains from the Paseo del Mar and Bosque beaches, Gulf of Mexico MAYLA A RAMOS-VAZQUEZ1
and JOHN S ARMSTRONG-ALTRIN2,*
1
Posgrado en Ciencias del Mar y Limnolog ı a, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Ciudad de Mexico 04510, CDMX, Mexico. 2 Unidad de Procesos Oceanicos y Costeros, Instituto de Ciencias del Mar y Limnolog ı a, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Ciudad de Mexico 04510, CDMX, Mexico . *Corresponding author. e-mail: [email protected] john˙[email protected] MS received 29 May 2020; revised 3 August 2020; accepted 5 August 2020
Microtextures of quartz and zircon grains from the Bosque and Paseo del Mar beaches in the Gulf of Mexico were examined using a Scanning Electron Microscopy (SEM), to infer their provenance and palaeoenvironment. A total of 16 microtextures from 200 grains were identiBed and were grouped into mechanical, chemical, and mechanical/chemical origin. Microtextures of mechanical origin represent parallel striations (ps), cracks due to collision (ck), conchoidal fractures (cf), v-shaped marks (vs), abrasion fatigue (af), meandering ridges (mr), chattermarks (ch), curved (cg) and straight grooves (sg), which are attributed to a high-energy Cuvial and sub-aqueous marine environment. Solution pits (sp), crystal overgrowth (cro), and silica globules (sgl) of chemical origin indicated precipitation and dissolution in a silica saturated marine environment. Adhered particles (ap), elongated depressions (dp), and relief are grouped as mechanical/chemical origin, suggested a sub-aqueous nearshore marine environment. Although zircon is considered as a resistant mineral, the frequency of microtextures observed was higher in zircon than in quartz. The results of this study revealed that the Los Tuxtlas volcanic Beld, Chiapas Massif and Oaxacan Complexes in the SW Gulf of Mexico are the potential source areas, which supplied sediments to the Paseo del Mar and Bosque beach areas. Keywords. Surface features; coastal sediments; heavy mineral; provenance; depositional environment; SEM.
1. Introduction Identifying microtextures on sand grains by SEM is one of the important techniques to infer transport process, their relation between source and sink, provenance, and paleoenvironment (Krinsley and McCoy 1977; Krinsley and Marshall 1987; Helland and Diffendal 1993; Mahaney 2002; Longhinos
2009; Smyth et al. 2014; Vos et al. 2014; Alam et al. 2019; Chen et al. 2019). SEM method also allows direct observation of minute microtextures on grain surface with high magniBcations up to 2 lm. Microtextures on grain surfaces are largely dependent on the transport agent and energy, hence it is possible to differentiate the microtextures originated by Cuvial, marine, aeolian, and glacial
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environments (Mahaney et al. 2001; Cawood et al. 2003; Immonen 2013; Wa
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