DOCSLIB.ORG

Chapter 8 Volcanic Activity in Mexico During the Holocene

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Chapter 8 Volcanic Activity in Mexico During the Holocene Chapter 8 Volcanic Activity in Mexico During the Holocene José L. Macías and José L. Arce Abstract This chapter presents an overview of the volcanic eruptions that have occurred in Mexico during the Holocene. Although volcanic regions are distributed all over the country, Holocene eruptions are mainly concentrated in the southern half of the country and, in particular, in the Trans-Mexican Volcanic Belt. Here, we summarize the details of the eruptions from the stratovolcanoes and monogenetic volcanoes, which have been extensively documented in the volcanological litera- ture, and their radiometric or historical dates. Out of the 153 Holocene eruptions described so far, ~63.4% have occurred at active stratovolcanoes and calderas, while the remaining ~36.6% have occurred from vents within monogenetic volcanic fields. Surprisingly, it seems that volcanism increased through time from Early (~17.7%), Middle (~26.8%) to Late Holocene (~55.5%). These figures may be biased because younger deposits are better preserved than older ones, and the latter usually are eroded through time especially around active stratovolcanoes. Around 24 eruptions (~15.6%) have taken place in pre-Hispanic and historical time out of which 11 occurred during the Little Ice Age. These eruptions have posed a serious threat to the surrounding regions and their populations. Some stratovolcanoes have collapsed at least once, covering and destroying previous deposits and making it difficult to reconstruct past eruption records. Large, Plinian to sub-Plinian eruptions at stratovolcanoes are well recorded in the stratigraphy, but the small eruptions that did not produce widespread deposits are difficult to define. Eruptions from monoge- netic volcanic fields were fed from central vents and fissures and mostly dominated by Strombolian activity and lava flows. The Holocene-collected data suggests that J. L. Macías (*) Instituto de Geofísica, Unidad Michoacán, Universidad Nacional Autónoma de Mexico, Antigua Carretera a Pátzcuaro, Morelia, Michoacán, Mexico e-mail: [email protected] J. L. Arce Instituto de Geología, Departamento de Procesos Litosféricos, Universidad Nacional Autónoma de México, Coyoacán, Mexico City, Mexico e-mail: [email protected] © Springer Nature Switzerland AG 2019 129 N. Torrescano-Valle et al. (eds.), The Holocene and Anthropocene Environmental History of Mexico, https://doi.org/10.1007/978-3-030-31719-5_8 130 J. L. Macías and J. L. Arce an eruption has taken place every ~65 years in Mexican territory during the past 10 ka. Monogenetic volcanoes should not be underestimated because at least 56 volcanoes have been created in Mexico during the Holocene, yielding an average recurrence of ~176 years. This chapter stresses the need to improve our knowledge of Holocene volcanism (e.g. still limited studies in some volcanoes) aimed to define average recurrence intervals and provide the data for probabilistic studies and haz- ard assessment to reduce future volcanic hazards. Keywords Volcanism · Stratovolcanoes · Monogenetic fields · Geological · Historical · Modern records Introduction At first glance, Holocene volcanic areas in Mexico may appear in most parts of the territory (Fig. 8.1). However, this young volcanism is mainly concentrated in the Trans-Mexican Volcanic Belt (TMVB), the Chiapanecan Volcanic Arc (CVA), Fig. 8.1 Sketch map of tectonic settings in Mexico with boundaries of lithospheric plates and main volcanic regions. Abbreviations: TMVB, Trans-Mexican Volcanic Belt; CAVA, Central American Volcanic Arc; CVA, Chiapanecan Volcanic Arc; LTVF, Los Tuxtlas Volcanic Field; PVF, Pinacate Volcanic Field; SQ, San Quintin; TV, Tres Vírgenes Volcanic Complex; Cp, Cerro Prieto; Ja, Jaraguay; SB, San Borja; So, Socorro; Pa, Roca Partida; Be, San Benedicto; Cla, Clarión; Ce, Ceboruco; Co, Colima; P, Parícutin; Jo, Jorullo; Nt, Nevado de Toluca; Po, Popocatépetl; Pi, Pico de Orizaba; Pe, Cofre de Perote; Ch, Chichón; and Ta, Tacaná 8 Volcanic Activity in Mexico During the Holocene 131 the northwestern edge of the Central American Volcanic Arc (CAVA) and in random sites in Baja California (San Quintin volcanic fields), in El Pinacate Volcanic Field in Sonora (NW Mexico), and in the Revillagigedo Archipelago that is located at 700 km west of Manzanillo (see Fig. 8.1). Holocene volcanism has occurred from stratovolcanoes and monogenetic volcanic fields, and it has been explosive and effu- sive in nature (Schmincke 2004). Holocene volcanoes have experienced different types of eruptions including those associated with flank failure (i.e. Colima Volcano), Plinian to sub-Plinian columns (large magnitude in most stratovolcanoes as Popocatépetl and Nevado de Toluca), dome destruction (i.e. Colima), Strombolian activity (i.e. Paricutin Volcano), and lava flows (i.e. Pico de Orizaba and Ceboruco volcanoes; Alcalá-Reygosa et al. 2018; Nelson 1980). Stratovolcanoes form the big- gest volcanic structures for instance Popocatépetl, Nevado de Toluca, and Tacaná volcanoes, constituted by an overlapping of lavas and pyroclastic deposits, record- ing several eruptive events intercalated by long quiescent periods (thousands of years) and recording important chemical changes through its volcanic history (Smith and Németh 2017). Meanwhile, monogenetic volcanoes are small structures that record a single eruptive event (i.e. Paricutin, Jorullo, and Xitle volcanoes) that can last for several years but also with small changes in chemical composition (Smith and Németh 2017). Clusters of volcanic vents formed by scoria cones and lava domes, maars and small shield volcanoes, whose products were erupted in a relatively short period (<2 Ma) with similar petrologic composition (mostly mafic) and are associated with tectonic features (e.g. basins, rifts, fractures or fault sys- tems) are defined as volcanic fields (i.e. Connor and Conway2000 ). Some examples in Mexico include the Pinacate, San Quintín, Jaraguay, San Borja, Michoacán- Guanajuato, Chichinautzin, Apan–Tezontepec, Serdan Oriental, Xalapa, and Tuxtla Volcanic Fields. In this chapter, we summarize the current knowledge of Holocene volcanic activ- ity in Mexico in the light of recent research in different areas. The boundary of the Pleistocene–Holocene has been defined in the Greenland NGRIP2 ice core at age 11.7 ka b2k (before AD 2000; Walker et al. 2008, 2009). In this interval of time, we were able to compile the date and age of 153 well-constrained eruptions that left traceable deposits or produced new monogenetic volcanoes. The chronology of these eruptions was identified by stratigraphic relationships,14 C dates of paleosol and charcoal embedded in the deposits, some limited 40Ar/39Ar and exposure 36Cl ages, 230U-Th in zircons, and paleomagnetic determinations (Table 8.1). For the sake of simplicity, all dates mentioned in the text correspond to calibrated dates (cal. yr. BP) using the IntCal13 (Reimer et al. 2013) calibration curve, and 2σ range is included in Table 8.1. Some deposits of a single eruption (i.e. pink pumice of Popocatépetl; Siebe et al. 1996) have multiple 14C results for which we used the best estimation considered by the authors. Two volcanoes have been so active, Colima Volcano, Popocatépetl, in historical times that we have combined all their modern activity into a single eruption, that is 1962–2019 and 1994–2019, respectively. Other volcanoes as Tacaná in Chiapas-Guatemala resumed phreatic activity in 1949 and 1986, however, we did not count these events as proper eruptions because they did not produce juvenile material or traceable deposits. J. L. Macías and J. L. Arce Table 8.1 Database of all Holocene eruptions reported for stratovolcanoes, calderas, and monogenetic volcanoes in México 132 Location Sample Method Conventional age Calibrated age 2σ range Volcanic landform North West Type (‰) yr. BP. (yr. BP) Reference Stratovolcanoes Everman Lomas Coloradas basalt Charcoal in lacustrine 14C 4690 ± 270 6002–4628 1 sediments 1848 Historical record N.A. 2 1896 Historical record N.A. 2 May 22, 1951 Historical record N.A. 2 January 29, 1993 Modern record N.A. 2 Ceboruco Destiladero lava flow Based on stratigraphic position N.A. >1088 3 Jala Pumice 21°10′42″ 104°32′37″ Charcoal in paleosol below Jala 14C 1060 ± 55 1197–1022 3 Pumice Copales lava flow Based on stratigraphic position N.A. <1060 3 Cajón lava flow Based on stratigraphic position N.A. <1060 3 Coapan I lava flow Based on stratigraphic position N.A. <1060 3 El Norte lava flow Based on stratigraphic position N.A. <1528 3 Ceboruco lava flow Based on stratigraphic position N.A. <1528 3 1870–1875 lava flow Historical record N.A. Colima Paleofuego Unit H 14C 9770 ± 60 11,305–10,882 4 Mesa Yerbabuena DAD n.d. n.d. Charcoal in DAD 14C 9671 ± 88 11,231–10,756 5 Unit J n.d. n.d. Charcoal in pyroclastic deposit 14C 7750 ± 60 8510–8177 4 Unit K 14C 7530 ± 80 8510–8176 4 Unit L 14C 7520 ± 50 8409–8202 4 8 Unit M 14C 7070 ± 60 8008–7761 4 Volcanic Activity in MexicoVolcanic During the Holocene Alvarez–Coquimatlan DAD n.d. n.d. Charcoal in DAD 14C 7040 ± 160 8175–7590 6 Unit N 14C 6950 ± 50 7925–7679 4 Unit O 14C 6150 ± 40 7164–6943 4 Unit P 14C 5980 ± 50 6942–6678 4 Unit Q 14C 5850 ± 60 6791–6497 4 Unit R 14C 5550 ± 80 6498–6189 4 Unit S 14C 5430 ± 50 6312–6021 4 Unit T n.d. n.d. Charcoal in pyroclastic deposit 14C 4810 ± 50 5645–5333 4 Unit U 14C 4740 ± 40 5586–5326 4 Unit V n.d. n.d. Charcoal in pyroclastic deposit 14C 4540 ± 60 5445–4975 4 Unit W 14C 4480 ± 60 5309–4889 4 Unit Y n.d. n.d. Charcoal in pyroclastic deposit 14C 4460 ± 40 5295–4894 4 Unit X 14C 4380 ± 80 5286–4834 4 Fuego de Colima Los Ganchos DAD n.d. n.d. Charcoal in DAD 14C 3600 ± 120 4245–3587 7 El Remate DAD n.d. n.d. Charcoal in DAD 14C 2690 ± 40 2861–2748 8 Unit Z n.d.
Load more

Recommended publications
  • Mantle Peridotite Xenoliths
    Earth and Planetary Science Letters 260 (2007) 37–55 www.elsevier.com/locate/epsl Mantle peridotite xenoliths in andesite lava at El Peñon, central Mexican Volcanic Belt: Isotopic and trace element evidence for melting and metasomatism in the mantle wedge beneath an active arc ⁎ Samuel B. Mukasa a, , Dawnika L. Blatter b, Alexandre V. Andronikov a a Department of Geological Sciences, University of Michigan, Ann Arbor, MI 48109-1005, USA b Department of Earth and Planetary Science, University of California, Berkeley, CA 94720, USA Received 6 July 2006; received in revised form 3 May 2007; accepted 7 May 2007 Available online 13 May 2007 Editor: R.W. Carlson Abstract Peridotites in the mantle wedge and components added to them from the subducting slab are thought to be the source of most arc magmas. However, direct sampling of these materials, which provides a glimpse into the upper mantle beneath an active margin, is exceedingly rare. In the few arc localities where found, peridotite xenoliths are usually brought to the surface by basaltic magmas. Remarkably, the hornblende-bearing ultramafic xenoliths and clinopyroxene megaxenocrysts from El Peñon in the central Mexican Volcanic Belt were brought to the surface by a Quaternary high-Mg siliceous andesite, a rock type usually considered too evolved to be a direct product of mantle melting. The xenoliths and megaxenocrysts from El Peñon represent lithospheric mantle affected by significant subduction of oceanic lithosphere since as early as the Permian. Trace element and radiogenic isotope data we report here on these materials suggest a history of depletion by melt extraction, metasomatism involving a fluid phase, and finally, limited reaction between the ultramafic materials and the host andesite, probably during transport.
    [Show full text]
  • Whale Shark Rhincodon Typus Populations Along the West Coast of the Gulf of California and Implications for Management
    Vol. 18: 115–128, 2012 ENDANGERED SPECIES RESEARCH Published online August 16 doi: 10.3354/esr00437 Endang Species Res Whale shark Rhincodon typus populations along the west coast of the Gulf of California and implications for management Dení Ramírez-Macías1,2,*, Abraham Vázquez-Haikin3, Ricardo Vázquez-Juárez1 1Centro de Investigaciones Biológicas del Noroeste, Mar Bermejo 195, Col. Playa Palo de Santa Rita, La Paz, Baja California Sur 23096, Mexico 2Tiburón Ballena México de Conciencia México, Manatí 4802, Col. Esperanza III, La Paz, Baja California Sur 23090, Mexico 3Asociación de Pesca Deportiva y Ecoturismo de Bahía de los Ángeles, Domicilio conocido Bahía de los Ángeles, Baja California 22980, Mexico ABSTRACT: We used photo-identification data collected from 2003 through 2009 to estimate pop- ulation structure, site fidelity, abundance, and movements of this species along the west coast of the Gulf of California to make recommendations for effective conservation and management. Of 251 whale sharks identified from 1784 photographs, 129 sharks were identified in Bahía de Los Ángeles and 125 in Bahía de La Paz. Only juveniles (mostly small) were found in these 2 bays. At Isla Espíritu Santo, we identified adult females; at Gorda Banks we identified 15 pregnant females. High re-sighting rates within and across years provided evidence of site fidelity among juvenile sharks in the 2 bays. Though the juveniles were not permanent residents, they used the areas regularly from year to year. A proportion of the juveniles spent days to a month or more in the coastal waters of the 2 bays before leaving, and periods of over a month outside the study areas before entering the bays again.
    [Show full text]
  • Preliminary Volcano-Hazard Assessment for Augustine Volcano, Alaska
    DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY Preliminary Volcano-Hazard Assessment for Augustine Volcano, Alaska by Christopher F. Waythomas and Richard B. Waitt Open-File Report 98-106 This report is preliminary and subject to revision as new data become available. Any use of trade, product or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Geological Survey Alaska Volcano Observatory Anchorage, Alaska 1998 U.S. DEPARTMENT OF THE INTERIOR BRUCE BABBITT, Secretary U.S. GEOLOGICAL SURVEY Thomas J. Casadevall, Acting Director For additional information: Copies of this report may be purchased from: U.S. Geological Survey U.S. Geological Survey Alaska Volcano Observatory Branch of Information Services 4200 University Drive Box 25286 Anchorage, AK 99508 Denver, CO 80225-0286 CONTENTS Summary of hazards at Augustine Volcano....................................... 1 Introduction ............................................................... 3 Purposeandscope ...................................................... 3 Physical setting of Augustine Volcano ...................................... 4 Relation to previous studies on Augustine hazards ............................. 5 Prehistoric eruptive history ................................................... 5 Historical eruptions ......................................................... 8 Hazardous phenomena at Augustine Volcano ..................................... 8 Volcanic hazards ....................................................... 12 Volcanicashclouds
    [Show full text]
  • COV4 Meeting Schedule Monday, 23 January, 2006
    COV4 Meeting Schedule Monday, 23 January, 2006 Sala 1 (large)† 8H15 Welcoming Statements 8H30 Invited Speaker M. Hall: LIVING WITH VOLCANOES 9H00 - 9H30 Invited Speaker A. Lavell: SOCIETY AND RISK: RISK MANAGEMENT AND VOLCANIC HAZARDS 9H30 - 10H00 Plenary Symposium IV-B: Monitoring Volcanoes J. EWERT: ASSESSING VOLCANIC THREAT AND PRIORITIZING VOLCANO MONITORING IN THE UNITED STATES 10H00 - Plenary Symposium II: Ash Falls and Aerosols 10H30 W. Rose: ASH-FALL AND AEROSOLS, AN OVERVIEW 10H30 - 11H00 Coffee Break Sala 1 (large) Sala 2 (medium) IV-B: Monitoring Volcanoes II: Ash Falls and Aerosols Chairs: J. Ewert, A. García, H. Kumagai & J. Chairs: J.-L. Le Pennec, C. Connor, T. Johnson Casadevall, D. Johnston & D. Schneider 11H00 - S. Carn: MONITORING GLOBAL VOLCANIC A. Neri: ASSESSING ASH FALL HAZARD 11H20 DEGASSING WITH OMI FROM WEAK EXPLOSIVE PLUMES 11H20 - C. Oppenheimer: NEW DEVELOPMENTS IN C. Bonadonna: PROBABILISTIC MODELLING 11H40 VOLCANIC GAS SURVEILLANCE OF TEPHRA DISPERSON 11H40 - B. Galle: DEVELOPMENT OF OPTICAL B. Houghton: PROXIMAL TEPHRA HAZARDS: 12H00 REMOTE SENSING INSTRUMENTS FOR RECENT ERUPTION STUDIES APPLIED TO VOLCANOLOGICAL APPLICATIONS VOLCANIC RISK IN THE AUCKLAND VOLCANIC FIELD, NEW ZEALAND 12H00-12H20 F. Donnadieu: ERUPTION DYNAMICS OF P. Baxter: GRAIN SIZE ANALYSIS OF ARENAL VOLCANO, COSTA RICA: INSIGHTS VOLCANIC ASH FOR THE ASSESSMENT OF FROM DOPPLER RADAR AND SEISMIC HEALTH HAZARD MEASUREMENTS 12H20 - 14H00 Lunch in the Centro Cultural Metropolitano- Plaza Grande IV-B: Monitoring-Cont. II: Ash- Cont. 14H00- A. Gerst: REAL-TIME 4D MONITORING OF D. Andronico: ASH EMISSIONS AT THE 14H20 ERUPTIVE PROCESSES WITH DOPPLER SUMMIT OF ETNA DURING THE 2004-05 RADARS- A NEW TOOL FOR HAZARDS FLANK ERUPTION MITIGATION AND VOLCANO SCIENCE 14H20-14H40 M.
    [Show full text]
  • Chemical and Isotopic Studies of Monogenetic Volcanic Fields: Implications for Petrogenesis and Mantle Source Heterogeneity
    MIAMI UNIVERSITY The Graduate School Certificate for Approving the Dissertation We hereby approve the Dissertation of Christine Rasoazanamparany Candidate for the Degree DOCTOR OF PHILOSOPHY ______________________________________ Elisabeth Widom, Director ______________________________________ William K. Hart, Reader ______________________________________ Mike R. Brudzinski, Reader ______________________________________ Marie-Noelle Guilbaud, Reader ______________________________________ Hong Wang, Graduate School Representative ABSTRACT CHEMICAL AND ISOTOPIC STUDIES OF MONOGENETIC VOLCANIC FIELDS: IMPLICATIONS FOR PETROGENESIS AND MANTLE SOURCE HETEROGENEITY by Christine Rasoazanamparany The primary goal of this dissertation was to investigate the petrogenetic processes operating in young, monogenetic volcanic systems in diverse tectonic settings, through detailed field studies, elemental analysis, and Sr-Nd-Pb-Hf-Os-O isotopic compositions. The targeted study areas include the Lunar Crater Volcanic Field, Nevada, an area of relatively recent volcanism within the Basin and Range province; and the Michoacán and Sierra Chichinautzin Volcanic Fields in the Trans-Mexican Volcanic Belt, which are linked to modern subduction. In these studies, key questions include (1) the role of crustal assimilation vs. mantle source enrichment in producing chemical and isotopic heterogeneity in the eruptive products, (2) the origin of the mantle heterogeneity, and (3) the cause of spatial-temporal variability in the sources of magmatism. In all three studies it was shown that there is significant compositional variability within individual volcanoes and/or across the volcanic field that cannot be attributed to assimilation of crust during magmatic differentiation, but instead is attributed to mantle source heterogeneity. In the first study, which focused on the Lunar Crater Volcanic Field, it was further shown that the mantle heterogeneity is formed by ancient crustal recycling plus contribution from hydrous fluid related to subsequent subduction.
    [Show full text]
  • MAY 21 to 25, 2018
    Abstracts Volume MAY 21 to 25, 2018 7th international OLOT - CATALONIA - SPAIN DL GI 743-2018 ISBN 978-84-09-01627-3 Cover Photo: ACGAX. Servei d’Imatges. Fons Ajuntament d’Olot. Autor: Eduard Masdeu Authors: Xavier Bolós and Joan Martí Abstracts Volume MAY 21 to 25, 2018 Scientific Committee Members IN ALPHABETICAL ORDER Patrick BACHÈLERY Károly NÉMETH Observatoire de Physique du Globe de Clermont-Ferrand Massey University (New Zealand) and Laboratoire Magmas et Volcans (France) Oriol OMS Pierre BOIVIN Universitat Autònoma de Barcelona (Spain) Laboratoire Magmas et Volcans (France) Michael ORT Xavier BOLÓS Northern Arizona University (USA) Univesidad Nacional Autónoma de México (Mexico) Pierre-Simon ROSS Gerardo CARRASCO Institut National de la Recherche Scientifique (Canada) Universidad Nacional Autónoma de México (Mexico) Dmitri ROUWET Shane CRONIN Istituto Nazionale di Geofisica e Vulcanologia (Italy) The University of Auckland (New Zealand) Claus SIEBE Gabor KERESZTURI Universidad Nacional Autónoma de México (Mexico) Massey University (New Zealand) Ian SMITH Jiaqi LIU The University of Auckland (New Zealand) Chinese Academy of Sciences (China) Giovanni SOSA Didier LAPORTE Universidad Nacional Autónoma de México (Mexico) Laboratoire Magmas et Volcans (France) Gregg VALENTINE Volker LORENZ University at Buffalo (USA) University of Wuerzburg (Germany) Benjamin VAN WYK DE VRIES José Luís MACÍAS Observatoire de Physique de Globe de Clermont- Ferrand Universidad Nacional Autónoma de México (Mexico) and Laboratoire Magmas et Volcans (France)
    [Show full text]
  • INSTITUTO POTOSINO DE INVESTIGACIÓN CIENTÍFICA Y TECNOLÓGICA, A.C. POSGRADO EN GEOCIENCIAS APLICADAS Estudio Regional Del
    INSTITUTO POTOSINO DE INVESTIGACIÓN CIENTÍFICA Y TECNOLÓGICA, A.C. POSGRADO EN GEOCIENCIAS APLICADAS Estudio regional del Campo Volcánico de la Cuenca Serdán – Oriental a través de métodos potenciales. Tesis que presenta Nereida de la Paz Pérez Méndez Para obtener el grado de Maestra en Geociencias Aplicadas Director de Tesis Dr. Vsevolod Yutsis San Luis Potosí, SLP. Diciembre de 2017 2 Créditos Institucionales Esta tesis fue elaborada en la División de Geociencias Aplicadas del Instituto Potosino de Investigación Científica y Tecnológica, A.C., bajo la dirección del Dr. Vsevolod Yutsis Durante la realización del trabajo el autor recibió una beca académica del Consejo Nacional de Ciencia y Tecnología (No. 596331) y del Instituto Potosino de Investigación Científica y Tecnológica, A. C. ii A mis padres y hermanos por su apoyo, a Rob, por su infinita ayuda y amistad, a Gerardo por su ánimo y cariño en mis días grises, a mi familia potosina, Lupita Méndez, Juán Guerrero, Norma, J Carlos y Janabanana por quienes siempre me sentí querida y cuidada. iv Agradecimientos A mis Padres por su amor y apoyo incondicional a lo largo de toda mi vida, son mis pilares y mi fuerza. Mis hermanos Nora, Mabel, Teresa y Emmanuel quienes me consienten e inspiran a seguir adelante. A mi amigo y compañero el Mtro. Alejandro Cruz Palafox por su paciencia y ayuda al responder a mis infinitas preguntas y dudas, y por compartir largas jornadas de trabajo conmigo. A Angelina Candia, Rosaira Cruz y Claudia Rigel que siempre estuvieron para mí en todo este proceso, su amistad y conocimiento me motivaron a diario.
    [Show full text]
  • Ii \ T MEXICAN GRASSES in the UNITED STATES NATIONAL
    ■ . ~+j-,r?7-w- - i i - . \ t MEXICAN GRASSES IN THE UNITED STATES NATIONAL HERBARIUM. By A. S, Hitchcock INTRODUCTION. The following list of grasses, based entirely upon specimens in the United States National Herbarium, is a preliminary paper, in which the scattered data upon Mexican grasses have been brought together and arranged in a convenient form. The species included have been accepted, for the most part, in their traditional sense. It has been impracticable to examine the types of many of the earlier described species since these specimens are located in European herbaria. For this reason the synonymy has been confined mostly to those names that could be fixed by an examination of American types, or concerning the application of which there was little doubt. The largest number of unidentified names are found in Fournier's work on Mexican grasses.1 This results from the incomplete or unsatis- factory descriptions and from the fact that the specimens cited under a given species either may not agree with the diagnosis, or may belong to two or more species, at least in different herbaria. An examination of the original specimens will undoubtedly lead to the identification of the greater part of these names. There are several specimens that have been omitted from the list because they have not been identified and are apparently unde- scribed species. They belong to genera, however, that are much in need of critical revision and further study of them is deferred for the present. In subsequent articles it is hoped to work out the classifi- cation of the tropical American grasses upon a type basis KEY TO THE GENEBA.
    [Show full text]
  • Geology of Nevado De Toluca Volcano and Surrounding Areas, Central Mexico
    mch089 1 of 26 Geological Society of America Map and Chart Series MCH089 2002 Geology of Nevado de Toluca Volcano and surrounding areas, central Mexico *Armando García-Palomo, José Luis Macías, José Luis Arce Instituto de Geofísica, Universidad Nacional Autónoma de México, Coyoacán 04510, México D.F., México Lucia Capra Instituto de Geografía, Universidad Nacional Autónoma de México, Coyoacán 04510, México D.F., México Victor Hugo Garduño Departamento de Geología y Mineralogía, Instituto de Investigaciones Metalúrgicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Michoacán, México Juan Manuel Espíndola Instituto de Geofísica, Universidad Nacional Autónoma de México, Coyoacán 04510, México D.F., México ABSTRACT Nevado de Toluca is an andesitic-dacitic stratovolcano of Pliocene-Holocene age located in central Mexico. The volcano is built on a complex sequence of metamorphic and sedimentary formations of Jurassic-Cretaceous age, rhyolitic ignimbrites of late Eocene age, and massive andesitic lava flows of late Miocene. In the northwest corner of the map area, on top of this basement sequence, a complex andesitic-dacitic strato- volcano, San Antonio, and a series of andesitic-dacitic domes and cones of Pliocene– early Pleistocene age were also built. The first andesitic-dacitic emissions of Nevado de Toluca occurred 2.6 Ma and continued during late Pleistocene–Holocene time contem- porarily with basaltic to dacitic emissions of the Chichinautzin Volcanic Field in the eastern parts of the map area. Volcanism in the area has been controlled by the interplay of three fault systems active since late Miocene. These systems, from older to younger, are the Taxco-Querétaro Fault System (NNW–SSE), the San Antonio Fault System (NE–SW), and the Tenango Fault System (E–W).
    [Show full text]
  • Geology and Petrology of Volcán Ceboruco, Nayarit, Mexico: Summary
    Geology and petrology of Volcán Ceboruco, Nayarit, Mexico: Summary STEPHEN A. NELSON* Department of Geology and Geophysics, University of California, Berkeley, California 94720 INTRODUCTION 1870; Iglesias and others, 1877). The volcano is in the northwest- ern part of the Mexican Volcanic Belt at lat 2 I °7'.W'N, 104°30'W. Volcan Ceboruco is one of nine of Mexico's historically active It is crowned by two concentric calderas and rises to an elevation of volcanoes (Mooser and others, 1958), with a single documented 2,200 m, or about 1,100 m above the surrounding valley of historical eruption during the period 1870—1875 (Caravantes, Ahuacatlan. Tertiary rhyolitic ash-flow tuffs crop out on both sides of the valley of Ahuacatlan and probably underlie Volcan * Present address: Department of Geology, Tulane University, New Or- Ceboruco. leans, Louisiana 701 18. The complete article, of which this is a summary, appears in Part II of the Bulletin, no. 1 1, p. 2290 —2431. Geological Society of America Bulletin, Part I, v. 91, p. 639-643, 3 figs., November 1980, Doc. no. S01 102. Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/91/11/639/3429689/i0016-7606-91-11-639.pdf by guest on 29 September 2021 Figure 1. Geologic map of Volcán Ceboruco and surrounding area. Inset shows loca- tion of Ceboruco relative to the other active volcanoes of Mexico (from west to east: Col- ima, Paricutin, Jorullo, Xitli, Popocateptl, Orizaba, and San Martin. Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/91/11/639/3429689/i0016-7606-91-11-639.pdf by guest on 29 September 2021 VOLCÁN CEBORUCO, MEXICO: SUMMARY 641 Figure 2.
    [Show full text]
  • Radiocarbon Ages of Lacustrine Deposits in Volcanic Sequences of the Lomas Coloradas Area, Socorro Island, Mexico
    Radiocarbon Ages of Lacustrine Deposits in Volcanic Sequences of the Lomas Coloradas Area, Socorro Island, Mexico Item Type Article; text Authors Farmer, Jack D.; Farmer, Maria C.; Berger, Rainer Citation Farmer, J. D., Farmer, M. C., & Berger, R. (1993). Radiocarbon ages of lacustrine deposits in volcanic sequences of the Lomas Coloradas area, Socorro Island, Mexico. Radiocarbon, 35(2), 253-262. DOI 10.1017/S0033822200064924 Publisher Department of Geosciences, The University of Arizona Journal Radiocarbon Rights Copyright © by the Arizona Board of Regents on behalf of the University of Arizona. All rights reserved. Download date 28/09/2021 10:52:25 Item License http://rightsstatements.org/vocab/InC/1.0/ Version Final published version Link to Item http://hdl.handle.net/10150/653375 [RADIOCARBON, VOL. 35, No. 2, 1993, P. 253-262] RADIOCARBON AGES OF LACUSTRINE DEPOSITS IN VOLCANIC SEQUENCES OF THE LOMAS COLORADAS AREA, SOCORRO ISLAND, MEXICO JACK D. FARMERI, MARIA C. FARMER2 and RAINER BERGER3 ABSTRACT. Extensive eruptions of alkalic basalt from low-elevation fissures and vents on the southern flank of the dormant volcano, Cerro Evermann, accompanied the most recent phase of volcanic activity on Socorro Island, and created 14C the Lomas Coloradas, a broad, gently sloping terrain comprising the southern part of the island. We obtained ages of 4690 ± 270 BP (5000-5700 cal BP) and 5040 ± 460 BP (5300-6300 cal BP) from lacustrine deposits that occur within volcanic sequences of the lower Lomas Coloradas. Apparently, the sediments accumulated within a topographic depression between two scoria cones shortly after they formed. The lacustrine environment was destroyed when the cones were breached by headward erosion of adjacent stream drainages.
    [Show full text]
  • The Aztlán Fault System: Control on the Emplacement of the Chichinautzin Range Volcanism, Southern Mexico Basin, Mexico. Seismic and Gravity Characterization
    The Aztlán Fault System: Seismic and gravity characterization 315 Boletín de la Sociedad Geológica Mexicana Volumen 67, núm. 2, 2015, p. 315-335 D GEOL DA Ó E G I I C C O A S 1904 M 2004 . C EX . ICANA A C i e n A ñ o s The Aztlán Fault System: control on the emplacement of the Chichinautzin Range volcanism, southern Mexico Basin, Mexico. Seismic and gravity characterization José Oscar Campos-Enríquez1,*, Javier Francisco Lermo-Samaniego2, Yanet Teresa Antayhua-Vera3, Marcos Chavacán3, Victor-Manuel Ramón-Márquez3,4 1 Instituto de Geofísica, Universidad Nacional Autónoma de México, México, D.F., México. 2 Instituto de Ingeniería, Universidad Nacional Autónoma de México, México, D.F., México. 3 Programa de Posgrado de Ciencias de la Tierra, Universidad Nacional Autónoma de México, D.F., Mexico. 4 Facultad de Ingeniería, Benemérita Universidad Autónoma de Puebla, Puebla, México. * [email protected] Abstract Gravity and seismic studies enabled us to establish the major features of the shallow crustal structure beneath Chichinautzin Range. Accordingly, the Chichinautzin Range evolved above Mesozoic calcareous rocks lying on a metamorphic basement. To the north and south this basement is downfaulted. Nevertheless the north dipping faults downward displace the basement to larger depths (2 to 3 km) in the Mexico and Toluca basins. In the Morelos Basin, the basin is shallower. As block-faulting evolved, the basement edge migrated southwards, thus widening an E-W oriented major depression south of the Mexico Basin. In particular, gravity modeling enabled us to integrate the different faults mapped up to today in and around the Chichinautzin Range into a fault system that can be correlated from the Nevado de Toluca.
    [Show full text]