A Syngenetic Perspective
E-Book, Englisch, 172 Seiten
ISBN: 978-0-12-803185-8
Verlag: Elsevier Science & Techn.
Format: EPUB
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Jean Pierre Bergoeing is a French Geomorphologist and polyglot, studied at the Pontifical Catholic University of Chile. He continued his studies at the University of Aix-Marseille II, France, where he successively obtained a Master's degree in Physical Geography (1972), a 3rd cycle Doctorate in Geomorphology (1975) and finally a State Doctorate in Letters and Human Sciences (1987). His career has developed in three continents, America, Europe and Africa. He has been Professor of the Pontifical Catholic University of Chile, Nantes University of France, Abdou Moumouni University of Niamey, Niger, and the University of Costa Rica. He has also worked for the French Government as international aid worker and later served a diplomatic career as a Scientific and Technical cooperation Attaché. He is the author of several books and numerous publications in international journals, and geomorphic maps on Chile, Costa Rica, Central America, Africa and Europe - including Geomorphology of Central America (Elsevier, June 2015).
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Chapter 3 Geomorphological Landscapes of Guatemala
Abstract
Guatemala forms part of the northern isthmus. It suffered several orogenic periods during its geological past; also, there is evidence of the last glacial period in the Cuchumatanes high plateau. The creation of the Sierra Madre volcanic range, which stretches from southwest Mexico through Guatemala into Honduras, occurred during the Quaternary period. Keywords Sierra Madre’s volcanic range Alto Cuchumatanes glacial past Peten karst plain Collapsed calderas Contents The Humid Peten Tropical Plain 19 Izabal Lake Tectonic System 20 Alto Cuchumatanes, a Glacial Past 23 Guatemala's Sierra Madre, Volcanic Range 23 Santa Maria or Gaxanul Volcanic Complex 24 Atitlan Caldera 26 Fuego Volcanic Mountain Range 26 Fuego Volcano 26 Agua Volcano 27 Pacaya Volcano 28 Amatitlan Lake 28 Sinkholes in Guatemala City 28 Tecuamburro Volcano 30 Collapsed Calderas 30 Ayarza Collapsed Caldera 30 Retana Collapsed Caldera 31 The Southern Volcanic Structures 32 Tahual Volcano 32 Flores or Amayo Volcano 32 Moyuta Volcano 32 The Pacific Plain 33 Guatemala is a country of great physical contrasts, where the Peten jungle plains are juxtaposed with the vigorous mountain relief of the Alto Cuchumatanes Range and the Quaternary volcanic range, descending steeply on the Pacific coastal plain. The Humid Peten Tropical Plain
The great Peten plain is located in northeast Guatemala and covers an area of 13,843 mi2, covered with a thick rainforest that rests on floods deposited from the Cretaceous and Tertiary periods to the present day. The floods are brought by the large hydrographic network that runs through the plain, particularly the Usumacinta River, which forms the plain's west Mexican border. The subsoil is characterized by a sedimentary series, with abundant limestone of the Cretaceous period that gives it particular karst morphology, shown by collapsed doline landscapes called “Cenotes” by the Mayan. The area emerged from the sea during the Miocene, about 15 million years ago. Four large geomorphological sectors dominate this region, based on its lithology and modeling. Yucatan vast platform. This area extends from the north to the vicinity of Peten Itza Lake. It is a low plateau, formed by monocline series of sandstones and limestone, marls and plaster, belonging to the period from the late Cretaceous to the Eocene. It is an extension of the Yucatan Peninsula and covers fine sediments in rivers and decomposing material in situ. It is subject to deep karstic dissolution. Peten Itza Lake central depression. The subsoil is composed by the Lacandon folded Cretaceous sedimentary series that conditions the east-west elongated Peten Itza Lake, which was formed to the east in contact with the first foothills of the Mayan Mountains. The lake is a natural intermediate boundary between the Yucatan platform occupied by agricultural work and the south dominated by the karstic relief covered with tropical vegetation. Situated 109.36 yd above sea level, the lake covers an area of 38.224 mi2; it is the third largest lake of Guatemala, after Izabal Lake and Atitlan Lake. Its maximum depth reaches 184.8 yd. Currently, Peten Itza Lake levels rise gradually because the lake receives more water, which evaporates. It is home of the Itzaes Mayas, who named the lake “waters of the witcher.” They were the last aborigines to be conquered by the Spaniards (Figure 3.1). Figure 3.1 Peten Itza Lake and Noh Peten City, in Flores Island. Aerial photography courtesy of www.Oirsa.org. Southern dissolution karst plateau. This plateau extends to the south of Peten Itza Lake. Same high reliefs, though profoundly altered, is constituted by a series of limestone dissolution under karst. The results are a combination of tropical rainfall, associated with the acidity introduced by the decomposition of the tropical vegetation in a basement of calcium magnesium carbonates, dating back to the late Miocene. This plateau, formed in the sea, emerged during the latest orogenesis. Mayan mountain range. Located in northeastern Peten, the Mayan mountain range is the highest area where few agricultural activities are implanted, because most of the territory is covered by tropical rainforest. The altitudes vary from 656.17 to 1312.3 yd. It is a landscape of rolling mountains, forming a tropical, multi-convex relief. Its origins date back to the Carboniferous and Permian periods (Figure 3.2). Figure 3.2 Peten and Peten Itza Lake sectors: 1—Yucatan karstic plateaus (Cretaceous); 2—Folded Lacandon formations (Cretaceous); 3—Mayan interior plain (Miocene-Tertiary); 4—Mayan Mountain reliefs (Carboniferous to Permian). Photo interpretation by J.P. Bergoeing, 2011, based on Unipesca, Guatemala, 2010. Izabal Lake Tectonic System
Izabal Lake is a tectonic deformation sector due to the presence of the transforming Motagua-Polochic fault. It has an arched movement of left lateral direction and is inserted into the fault system, which marks the boundary between the North American plate (to the north) and the Caribbean plate (to the south). The rocks that make up this unit date back to the Permian (Cholchal formation). The sector is consistent with the orogenic deformations of the Paleozoic geosynclines (Carboniferous and Permian), dominated by serpentine and meta-volcanic rocks that were later folded and faulted. Left diverging failures of Motagua and Polochic are complex. They would have 9-mi depth and a displacement speed of 0 25/32 in/year, and would be reduced to 0 19/32 in/year in the sector of the Triple Union (Caribbean, Cocos, and North American plates) (Franco, 2008). The Motagua-Polochic fault is the tectonic boundary between the North American plate, as previously mentioned, and the Caribbean plate forms the Southern Chortis block. In this sector, the fluviolacustrine system of Izabal Lake focuses on its tributaries—the Polochic River (149 mi. long), Dulce River, and the Golfete—before flowing into the Amatique Bay (Caribbean Sea), where the main Caribbean port of Guatemala, Puerto Barrios, stands. Izabal Lake, which is 6691 9/64 in. deep (Brooks, 1969), is inserted in a tectonic depression bounded on the north by the Motagua failure and the Santa Cruz Mountains, and on the south by Las Minas Mountains. It is therefore a natural collector of the rainwater channeled by the numerous tributaries flowing into the Izabal Lake. The description of this sector would be incomplete without mentioning Motagua River, which after a journey of 248 mi, flows into the Honduras Gulf and remains the longest in the country (Figure 3.3). Figure 3.3 Motagua, Xichoy-Polochic, and Jocotan-Chamelecon transforming faults in Guatemala. Tectonic limits between North American, Caribbean, and Cocos plates. Photo interpretation by J.P. Bergoeing, 2012. Source: Geological map of the Guatemalan Republic (MAGA-IGN, 2001). Alto Cuchumatanes, a Glacial Past
The Huehuetenango Department in Guatemala stands out for the Cuchumatanes Mountains' end of the Sierra Madre Occidental Mountains of Mexico, which separates two slopes: a southwestern slope, where strong rivers descend, and a northeastern slope, birthplace of the Usumacinta and Selegua Rivers, heading to Mexico. It is also characterized by the highest summits in the country; among them is Alto Cuchumatanes Mountain, which exceeds 11,482 ft. This gives it the characteristics of having suffered the last Quaternary glacial layer. Deposits of glacial moraines, erratic blocks, and layers of ice were studied by several researchers (Anderson, 1969; Hastenrath, 1973; Lachniet, 2011). The latter determined that Wisconsinian parking ice covered a limestone plateau, north of Todos Los Santos de Cuchumatanes, covering about 23.166 mi2 (Lachniet...
