Origin of a sedimentary sequence on the north island of Todos Santos, B.C., Mexico
The Todos Santos Islands are located within Todos Santos Bay, Baja California. A small sedimentary sequence of about 160 m length and 18 m height is located on the north island. The fine sediments that constitute this unit are associated with conglomerates and interbedded sedimentary breccias. Struc...
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Iniversidad Autónoma de Baja California
1992
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oai:cienciasmarinas.com.mx:article-8862020-06-03T00:06:32Z Origin of a sedimentary sequence on the north island of Todos Santos, B.C., Mexico Origen del depósito sedimentario de la isla norte de Todos Santos, B.C., México Quintanilla-Montoya, AL Suárez-Vidal, F n/a n/a The Todos Santos Islands are located within Todos Santos Bay, Baja California. A small sedimentary sequence of about 160 m length and 18 m height is located on the north island. The fine sediments that constitute this unit are associated with conglomerates and interbedded sedimentary breccias. Structurally, this sequence is affected by normal faults with a NE-SW dominant strike and a slip to the East. Sedimentary structures in this sequence are found represented by mud cracks and raindrops, which are present in the lower part of the sequence. The sedimentary lithology basically consists of arkoses, clays, muds, tuffs and conglomerates, and the volcanics are basalts and andesites. Due to the lack of fossils, the age has been established through correlation with other sedimentary sequences known in the area such as: the Rosarito Beach Formation (Las Glorias Member), the basalts and tuffs of La Misión and El Descanso and the Coronado Islands. Therefore, we propose the age for this sedimentary sequence as Miocene. The source of the volcanic material was located to the west of the actual coastline and the sedimentary sequence originated to the east. Based on sedimentary structures and textures, this study determined that the depositional environment of the sedimentary sequence was subaerial, that the nature of the sediment is typical of an alluvial fan and that this sequence belongs to the proximal part of this. En la Bahía de Todos Santos, Baja California, se encuentran localizadas las islas de Todos Santos. En la isla norte se ubica un pequeño depósito sedimentario de alrededor de 160 m de longitud y 18 m de altura. Los sedimentos finos que constituyen esta unidad están asociados con conglomerados y brechas sedimentarias de forma intercalada. Estructuralmente, este depósito está afectado por fallas normales con rumbo predominante NE-SO y echado hacia el Este. Las estructuras sedimentarias primarias en esta secuencia se encuentran representadas por grietas de desecación y gotas de lluvia, las cuales se presentan en las partes bajas del depósito. El tipo de litología sedimentaria consta básicamente de arkosas, arcillas, timos, tobas y conglomerados, y la parte volcánica de andesitas y basaltos. Debido a la carencia de fósiles dentro del depósito, la determinación de la edad se establece mediante la correlación con otras secuencias sedimentarias ya conocidas como son: la Formación Rosarito Beach (Miembro Las Glorias), los basaltos y tobas de La Misión y El Descanso,y las Islas Coronado, proponiéndose el Mioceno como edad para dicho depósito. Lo anterior lleva implícito que la fuente del material volcánico se localizó al oeste de la actual línea de costa y que la secuencia sedimentaria tiene su origen al este. En este estudio se determinó, en función de las texturas y estructuras sedimentarias, que el ambiente de depositación fue subaéreo, que la naturaleza del sedimento es típica de un abanico aluvial y que este depósito sedimentario es la parte proximal de dicho abanico. Iniversidad Autónoma de Baja California 1992-03-06 info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Peer-reviewed Article Artículo Arbitrado application/pdf https://www.cienciasmarinas.com.mx/index.php/cmarinas/article/view/886 10.7773/cm.v18i1.886 Ciencias Marinas; Vol. 18 No. 1 (1992); 1-18 Ciencias Marinas; Vol. 18 Núm. 1 (1992); 1-18 2395-9053 0185-3880 eng https://www.cienciasmarinas.com.mx/index.php/cmarinas/article/view/886/808 |
| institution |
Ciencias Marinas |
| collection |
OJS |
| language |
eng |
| format |
Online |
| author |
Quintanilla-Montoya, AL Suárez-Vidal, F |
| spellingShingle |
Quintanilla-Montoya, AL Suárez-Vidal, F Origin of a sedimentary sequence on the north island of Todos Santos, B.C., Mexico |
| author_facet |
Quintanilla-Montoya, AL Suárez-Vidal, F |
| author_sort |
Quintanilla-Montoya, AL |
| title |
Origin of a sedimentary sequence on the north island of Todos Santos, B.C., Mexico |
| title_short |
Origin of a sedimentary sequence on the north island of Todos Santos, B.C., Mexico |
| title_full |
Origin of a sedimentary sequence on the north island of Todos Santos, B.C., Mexico |
| title_fullStr |
Origin of a sedimentary sequence on the north island of Todos Santos, B.C., Mexico |
| title_full_unstemmed |
Origin of a sedimentary sequence on the north island of Todos Santos, B.C., Mexico |
| title_sort |
origin of a sedimentary sequence on the north island of todos santos, b.c., mexico |
| description |
The Todos Santos Islands are located within Todos Santos Bay, Baja California. A small sedimentary sequence of about 160 m length and 18 m height is located on the north island. The fine sediments that constitute this unit are associated with conglomerates and interbedded sedimentary breccias. Structurally, this sequence is affected by normal faults with a NE-SW dominant strike and a slip to the East. Sedimentary structures in this sequence are found represented by mud cracks and raindrops, which are present in the lower part of the sequence. The sedimentary lithology basically consists of arkoses, clays, muds, tuffs and conglomerates, and the volcanics are basalts and andesites. Due to the lack of fossils, the age has been established through correlation with other sedimentary sequences known in the area such as: the Rosarito Beach Formation (Las Glorias Member), the basalts and tuffs of La Misión and El Descanso and the Coronado Islands. Therefore, we propose the age for this sedimentary sequence as Miocene. The source of the volcanic material was located to the west of the actual coastline and the sedimentary sequence originated to the east. Based on sedimentary structures and textures, this study determined that the depositional environment of the sedimentary sequence was subaerial, that the nature of the sediment is typical of an alluvial fan and that this sequence belongs to the proximal part of this.
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| publisher |
Iniversidad Autónoma de Baja California |
| publishDate |
1992 |
| url |
https://www.cienciasmarinas.com.mx/index.php/cmarinas/article/view/886 |
| _version_ |
1715724023831199744 |
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