Notes on the Geology of Eastern Guatemala and Northwestern Spanish Honduras

Powers, Sidney

doi:10.1086/622612

Cited by 12 publications

(13 citation statements)

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“…Pliocene (~5 Ma) Herrería Formation due to their similarity with outcrop observations near the city of Livingston ( Figure 2; Powers, 1918). However, the high-precision and high-accuracy geochronological data from the tuff layer deposited ~30 m above this unconformity yield a significantly older age of 12.06 Ma.…”

mentioning

confidence: 72%

“…One zircon yielded a notably older age of 13.862 ± 0.014 Ma (Table 1), and is interpreted as being an inherited grain. The presence of the tuff in the lower part of the Carboneras Formation suggests that the initial infill of the Lake Izabal Basin is Serravallian (Middle Miocene) in age and that the formation does not correlate to the Herrería Formation as defined by Powers (1918).…”

Section: Geochronology and Geochemistry Of The Volcanic Tuffmentioning

confidence: 97%

“…Stratigraphic information in the area surrounding the Lake Izabal Basin is limited to outcrop exposures to the east near the city of Livingston (e.g. Powers, 1918; Vinson, 1963), to industry reports from three wells drilled in the Amatique area (Shell, 1993; Figure 2), and to a series of outcrops along the western slopes of the Mico Mountains and the San Gil Hill area (Mota‐Vidaure, 1989; Figure 2). The geology of basement rocks, exposed in the Mico Mountains and San Gil Hill, is poorly constrained.…”

Section: Geological Setting Of the Lake Izabal Basinmentioning

confidence: 99%

“…Rocks surrounding the Mico Mountains were deposited in shallow marine and terrestrial environments (Mota‐Vidaure, 1989; Powers, 1918; Vinson, 1963). Three main formations have been described (Figure 3): (a) The Rio Dulce Formation rests unconformably on top of marine Permian limestones and Eocene shales and sandstones and is considered to be Upper Oligocene to Lower Miocene in age and it is interpreted to have formed before the formation of the Lake Izabal Basin in a marine setting (Vinson, 1963).…”

Section: Geological Setting Of the Lake Izabal Basinmentioning

confidence: 99%

“…Three main formations have been described (Figure 3): (a) The Rio Dulce Formation rests unconformably on top of marine Permian limestones and Eocene shales and sandstones and is considered to be Upper Oligocene to Lower Miocene in age and it is interpreted to have formed before the formation of the Lake Izabal Basin in a marine setting (Vinson, 1963). The formation consists of limestones that are light buff, tan and cream‐coloured with abundant coral, oyster, algal and mollusk fragments (Powers, 1918; Vaughan, 1919; Vinson, 1963). (b) The Rio Dulce Formation is overlain unconformably by the terrigenous Herrería Formation, which is constrained to the Plio‐Pleistocene based on freshwater gastropod shells (Powers, 1918).…”

Section: Geological Setting Of the Lake Izabal Basinmentioning

confidence: 99%

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The role of the Polochic Fault as part of the North American and Caribbean Plate boundary: Insights from the infill of the Lake Izabal Basin

et al. 2020

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The Lake Izabal Basin in Guatemala is a major pull-apart basin along the sinistral Polochic Fault, which is part of the North American and Caribbean plate boundary. The basin infill contains information about the tectonic and sedimentological processes that have imparted a significant control on its sedimentary section. The inception of the basin has been linked to the relative importance of the Polochic Fault in the tectonic history of the plate boundary; yet, its sedimentological record and its inception age have been poorly documented. This study integrates diverse datasets, including industry reports, well logs and reports, well cuttings, vintage seismic data, outcrop observations and geochronological data to constrain the initial infill and age of inception of the basin. The integrated data show that during the Oligocene-Miocene, a marine carbonate platform was established in the region which was later uplifted and eroded in the early Miocene. The fluvial-lacustrine deposits above this carbonate platform are part of the initial infill of the basin and are constrained with zircon weighted-mean 206 Pb/ 238 U ages of 12.060 ± 0.008 from a volcanic tuff ~30 m above the unconformity. Sandstone, mudstone and coal dominate the interval from 12 to 4 Ma, with an increase in conglomerate correlating to the uplift of the Mico Mountains and San Gil Hill at 4 Ma. Fault switch activity between the Polochic and Motagua faults has been hypothesized to explain total offset along the Polochic Fault and the geologic and geodetic slip rates along the two faults. The 12 Ma age determined for the initial infill of the basin confirms this hypothesis. Consequently, our study confirms that at ~12 Ma the Polochic Fault served as the main fault of the plate boundary with inferred slip rates ranging from 13 to 21 mm/yr with a strong possibility that the Polochic Fault was, at some point between 15 Ma and 7 Ma, the only active fault of the plate boundary. The results of this study show that tectonic records preserved in sediments of strike-slip basins improve the understanding of the relative significance of individual faults and the implications with respect to strain partitioning throughout its tectonic history.

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mentioning

confidence: 72%

Section: Geochronology and Geochemistry Of The Volcanic Tuffmentioning

confidence: 97%

Section: Geological Setting Of the Lake Izabal Basinmentioning

confidence: 99%

Section: Geological Setting Of the Lake Izabal Basinmentioning

confidence: 99%

Section: Geological Setting Of the Lake Izabal Basinmentioning

confidence: 99%

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