Revista Mexicana De Ciencias Geologicas最新文献

{"title":"A new coral family and three new genera from the Lower Cretaceous of Puebla and Sonora (Scleractinia; Mexico)","authors":"H. Löser","doi":"10.22201/cgeo.20072902e.2022.3.1698","DOIUrl":"https://doi.org/10.22201/cgeo.20072902e.2022.3.1698","url":null,"abstract":"Solitary corals currently assigned to the genus Plesiosmilia are common elements in Late Jurassic to Early Cretaceous coral faunas. The genus itself is poorly defined and its systematic position is questionable. Moreover, examination of type material has shown that the genus lumps corals of different morphologies. Here, one common coral type is separated in a new solitary coral genus as well as two new phaceloid coral genera with a comparable morphology. The three new and another three existing genera are collected in a new family. The newly described material comes from the Upper Valanginian-Lower Hauterivian of San Juan Raya (Puebla) and the Lower Albian of Rayón (Sonora, both Mexico).","PeriodicalId":49601,"journal":{"name":"Revista Mexicana De Ciencias Geologicas","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2022-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46017492","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microfacies y edades U–Pb en lutitas gasíferas del Cretácico Superior de las cuencas de Sabinas y Parras, NE de México","authors":"Aurea Yahaira González--Betancourt, E. González-Partida, A. Carrillo-Chávez, A. Iriondo","doi":"10.22201/cgeo.20072902e.2022.3.1696","DOIUrl":"https://doi.org/10.22201/cgeo.20072902e.2022.3.1696","url":null,"abstract":"En este trabajo se pretende observar los cambios en los patrones de sedimentación y fauna de las Formaciones Eagle Ford e Indidura que afloran en el estado de Coahuila. Estas sucesiones sedimentarias se depositaron dentro del rango Cenomaniano-Turoniano en el interior de la cuenca de Sabinas y se componen de facies arcillosas, carbonatadas, bioclásticas y arenosas. Fueron descritas nueve microfacies (Mf), la Mf-1 mudstone; la Mf-2 lutita y wackestone con foraminíferos oportunistas; la Mf-3 wackestone de foraminíferos especialistas, la Mf-4 wackestone y packstone de radiolarios; la Mf-5 wackestone y packstone con filamentos; la Mf-6 grainstone peloidal; la Mf-7 grainstone bioclástico; la Mf-8 calcarenitas; y la Mf-9 tobas volcánicas intercaladas en la sucesión. La ocurrencia del evento oceánico anóxico OAE-2 (OAE del inglés: Oceanic Anoxic Event) está presente dentro de la sucesión sedimentaria, indicado por los depósitos de lutitas negras ricas en materia orgánica, la muerte masiva de foraminíferos planctónicos, abundantes filamentos, cristales de pirita y las concentraciones elevadas de elementos redox como el V, Mo y Mn. Sin embargo, las condiciones de depósito presentan una variación en la concentración de oxígeno, micronutrientes y materia orgánica a lo largo de la paleogeografía. Elementos como Ni y Zn en las microfacies 1, 2, 3 y 4 evidencian una alta productividad, la cual está asociada a la presencia de organismos planctónicos y/o radiolarios. Otros elementos químicos como el Al, K y Zr muestran un incremento en el aporte de material detrítico dentro de la cuenca asociado a las microfacies arcillosas y arenosas. El contenido de materia orgánica es más elevado de la microfacies 2 a la 5 y además se considera de origen autóctono. La variación en las condiciones óxico-anóxicas es notoria gracias a la relación de foraminíferos planctónicos-bentónicos y las relaciones geoquímicas entre los elementos de Mo, Va, Ni y S. En la Formación Indidura las edades de U–Pb en granos de circón procedentes de capas de tobas restringen el depósito entre 98.2 ± 0.9 Ma a los 91.7 ± 0.8 Ma, es decir Cenomaniano- Turoniano, aunque la presencia de Praeglobotruncana a la base restringe el depósito al Cenomaniano tardío- Turoniano. Mientras que la edad de la Formación Eagle Ford está indicada por los géneros Rotalipora cushmani, Hedbergella y Helveglobotruncana helvética del Cenomaniano y Turoniano.","PeriodicalId":49601,"journal":{"name":"Revista Mexicana De Ciencias Geologicas","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2022-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48726902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Caracterización de las rocas metacarbonatadas y rocas adyacentes en el arroyo El Mezquite dentro del Complejo Plutónico de La Paz, Baja California Sur, México: sucesión de eventos geológicos en función de relaciones de campo y geocronología","authors":"Guillermo Camarena-Vázquez, José Antonio Pérez-Venzor, P. Schaaf, Tobias Schwennicke, Carlos Ortega-Obregón","doi":"10.22201/cgeo.20072902e.2022.3.1676","DOIUrl":"https://doi.org/10.22201/cgeo.20072902e.2022.3.1676","url":null,"abstract":"El Complejo Plutónico de La Paz (CPLP) está ubicado al sur de la península de Baja California. En este complejo se ha reportado la presencia de rocas calcosilicatadas asociadas a otras rocas metamórficas e intrusivas. El presente estudio fue enfocado al estudio de las rocas calcosilicatadas y rocas adyacentes que afloran en el arroyo El Mezquite, conformadas por una alternancia de: mármol, mármol impuro, rocas calcosilicatadas y gneis anfibolítico, que se extienden por más de dos kilómetros y agrupadas como una unidad informal llamada calcosilicatos El Mezquite. Las relaciones de campo junto con las características megascópicas y microscópicas, indican que las rocas metasedimentarias representan parte de un protolito calcáreo formado en un ambiente marino con mezcla de sedimentos siliciclásticos y volcaniclásticos, los cuales fueron metamorfizados posteriormente. En el arroyo El Mezquite además afloran rocas ígneas sin deformación de composición tonalítica así como gneis anfibolítico, ortogneis y migmatitas, estas últimas en el contacto entre los intrusivos sin deformación y las rocas calcosilicatadas. Las litologías y sus relaciones de campo evidencian dos eventos metamórficos, uno regional representado por el gneis anfibolítico y el ortogneis y otro de contacto, representado por las migmatitas. La tonalita y el gneis anfibolítico fueron fechados por el método de U-Pb en zircones y arrojaron edades de 85.4 ± 0.7 Ma y 116 ± 1.5 Ma, respectivamente, indicando dos eventos magmáticos. La primera edad la interpretamos indirectamente como la edad máxima del metamorfismo de contacto, mientras que, por las relaciones de campo, la edad de 116 ± 1.5 Ma permite inferir la edad mínima del depósito e indirectamente la edad máxima del metamorfismo regional. También se obtuvieron datos termométricos de la tonalita y del gneis anfibolítico a partir del Ti en zircón, obteniendo 636 ± 33 °C y 701 ± 42 °C, respectivamente. La presencia de minerales como diópsido, wollastonita y trazas de rutilo, indican temperaturas potencialmente mayores a 700 °C para el metamorfismo regional lo cual alcanzó facies de anfibolita. Las rocas calcosilicatadas se depositaron en la zona de transición entre la cuenca profunda y la plataforma continental, posteriormente afectadas por metamorfismo regional (<116 Ma) y un metamorfismo de contacto sobreimpreso (<85 Ma).","PeriodicalId":49601,"journal":{"name":"Revista Mexicana De Ciencias Geologicas","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2022-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48863229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"EDITORIAL. 20 años de investigación en el Centro de Geociencias (CGEO): desde los fundamentos geocientíficos hasta la multidisciplinariedad","authors":"Lucia Capra-Pedol","doi":"10.22201/cgeo.20072902e.2022.2.1701","DOIUrl":"https://doi.org/10.22201/cgeo.20072902e.2022.2.1701","url":null,"abstract":"Para celebrar los 20 años del Centro de Geociencias (CGEO) de la Universidad Nacional Autónoma de México (UNAM) se presenta una sección especial con artículos acerca de temas que identifican a la investigación que se realiza en este centro y que, a nivel internacional, están entre los de ... Para continuar, descargue el texto completo ","PeriodicalId":49601,"journal":{"name":"Revista Mexicana De Ciencias Geologicas","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2022-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42476990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The triple junction of the North America, Cocos, and Caribbean plates. What we know, what we don’t","authors":"M. Guzmán-Speziale","doi":"10.22201/cgeo.20072902e.2022.2.1666","DOIUrl":"https://doi.org/10.22201/cgeo.20072902e.2022.2.1666","url":null,"abstract":"We present a summary of the tectonic elements of the North America-Caribbean-Cocos triple junction area. In the vicinity of the triple junction, displacement related to the North America-Caribbean plate boundary takes place along the left-lateral Motagua-Polochic fault system, and convergence between the Cocos and the other two plates occurs along the Middle America trench. \u0000The trace of the Motagua-Polochic system is lost at its westernmost end and does not reach the convergent boundary. Deformation of the plate boundary in this location is then distributed along a system of reverse faults (the Reverse-faults tectonic province), a system of left-lateral faults (Strike-slip faults province), two or more large NW-SE oriented left-lateral faults (Angostura and Concordia faults), and a left-lateral fault (Tonalá) that might be construed as the continuation of the Polochic fault along the southern border of the Chiapas Massif. \u0000Somewhere within this deformation zone, transition in overriding plate between North America and Caribbean takes place, but it is not clear exactly where. It is probably at about longitude 96° W because both the dip and the shape of the subducted Cocos slab change significantly at this longitude.","PeriodicalId":49601,"journal":{"name":"Revista Mexicana De Ciencias Geologicas","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2022-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45476537","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Holocene and Upper Pleistocene stratigraphy of Xochimilco lake, central Mexico","authors":"B. Ortega‐Guerrero, Sandra G. García, G. Cruz, C. Salinas, M. Caballero, Ismerai Reyes, L. Caballero","doi":"10.22201/cgeo.20072902e.2022.2.1687","DOIUrl":"https://doi.org/10.22201/cgeo.20072902e.2022.2.1687","url":null,"abstract":"The lacustrine system developed in the basin of Mexico has been of great interest in studies of various geological and social disciplines. Its sediments preserve the history of the environmental changes that occurred during the late Quaternary. Between 2016 and 2018, a set of lacustrine sediment cores were collected in the Xochimilco sub-basin, located south of the basin of Mexico. From these sedimentary sequences, a master sequence was constructed that represents the upper 66.5 m of the lacustrine deposits. For the establishment of its stratigraphic column, 15 lithotypes were defined from their sedimentary components in which the clastic components made up of silicates dominate, mostly silt and clay in size. The most abundant biogenic fraction is diatoms that frequently form oozes, and ostracods are a common component in most of the sequence, which locally form hashes. Interbedded with the clastic and biogenic lithotypes are volcaniclastic deposits. Eight lithological units were defined based on their dominant lithotypes. The time scale of the sequence is still uncertain for the oldest sediments; however, it is estimated that it covers the last 300000 to 350000 years. From this temporality, environmental oscillations of millennial scales are inferred. Diatom-rich laminated sediments represent the deepest phases in the lake. The deposits with higher biogenic and authigenic calcareous components indicate the phases of higher ionic concentration during which the lake was shallower. The detailed analysis of the stratigraphy and the description of the sedimentary components in Xochimilco allows to establish an initial interpretation of the variations in the depositional environments, and provides the base from which the detailed studies of paleoclimatic indicators will be supported.","PeriodicalId":49601,"journal":{"name":"Revista Mexicana De Ciencias Geologicas","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2022-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41564678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Respuesta del sistema erosivo fluvial en las cuencas Ameca y Santiago, centro-occidente de México, ante el control tectónico y volcánico","authors":"Arturo Godínez-Tamay, Miguel Castillo-Rodríguez","doi":"10.22201/cgeo.20072902e.2022.2.1667","DOIUrl":"https://doi.org/10.22201/cgeo.20072902e.2022.2.1667","url":null,"abstract":"El volcanismo del Mioceno tardío asociado a la Faja Volcánica Trans-Mexicana modificó las rutas de transporte de sedimento proveniente del relieve del Oligoceno tardío-Mioceno temprano del centro-occidente de México. Se hipotetiza que los materiales de la Sierra Madre Occidental hubiesen llegado a la planicie aluvial del Graben de Puerto Vallarta. La actividad volcánica de la Faja Volcánica Trans-Mexicana al sur de la Sierra Madre Occidental posiblemente generó el cambio en el curso de la descarga de sedimentos provenientes de la Sierra Madre Occidental, hacia la planicie fluvial de Nayarit, a través del río Santiago. Este evento frenó el transporte de sedimentos provenientes de la Sierra Madre Occidental al Graben de Puerto Vallarta y la Bahía de Banderas y aisló una porción de relieve que actualmente corresponde a la cuenca del río Ameca, la cual suministra, hoy en día, los sedimentos que conforman la planicie fluvial del Graben de Puerto Vallarta. La distribución de edades de zircones detríticos del Oligoceno tardío al Mioceno temprano en las desembocaduras de las cuencas Santiago y Ameca, indica que ambas cuencas comparten sedimentos originados en la Sierra Madre Occidental.","PeriodicalId":49601,"journal":{"name":"Revista Mexicana De Ciencias Geologicas","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2022-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41267531","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chemical weathering in hardened volcanic horizons (tepetates) of the State of Mexico","authors":"O. Acevedo-Sandoval, F. Prieto-García, J. Prieto-Méndez, Yolanda Marmolejo-Santillán, C. Romo-Gómez","doi":"10.22201/cgeo.20072902e.2022.2.1644","DOIUrl":"https://doi.org/10.22201/cgeo.20072902e.2022.2.1644","url":null,"abstract":"Weathering is one of the most important phenomena that affect the balance dynamics of the Earth's crust. The chemical composition of soil samples and hardened horizons from seven profiles (P1 to P7) of the State of Mexico was compared to detect the degree of alteration by means of weathering indices. In hardened horizons, the dominant elements are SiO2, Al2O3, Na2O, K2O and TiO2, corresponding to 86.8 % of the total oxides. The weathering indices based on the mobility and immobilization of alkaline and alkaline earth elements reveal that the B horizons and the hardened horizons of profiles P4, P5, P6 and P7 are generally more altered than the surface horizons, therefore they have a greater pedogenic development. Profiles P1, P2 and P3 show incipient weathering. The geochemical indices and chemical relationships used in this study to evaluate weathering and associated basic alteration processes showed consistent results. These coincide in indicating incipient to moderate weathering acting in the seven profiles, with variable intensity in all the hardened horizons. The intensity variation defines a sequence of chemical weathering for the hardened horizons: P6> P4> P5> P7> P2> P3> P1, where P6 has the highest degree of weathering in the indices: CIA, CPA, CIA-K, CIW, PIA,IPark, V.","PeriodicalId":49601,"journal":{"name":"Revista Mexicana De Ciencias Geologicas","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2022-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45742792","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Frackita-v1: un código en Matlab® para el análisis de fracturas geológicas en 1D","authors":"Alberto Vásquez-Serrano","doi":"10.22201/cgeo.20072902e.2022.2.1692","DOIUrl":"https://doi.org/10.22201/cgeo.20072902e.2022.2.1692","url":null,"abstract":"En este trabajo se presenta el código Frackita-v1 escrito en MATLAB®, el cual es una herramienta de análisis unidimensional de fracturas geológicas que automatiza los cálculos de parámetros tales como: dimensión de caja, dimensión de correlación, exponente de Lyapunov, exponente de frecuencia acumulada, coeficiente de variación e intensidad de fracturas. Dichos parámetros son fundamentales para conocer la distribución del tamaño de las fracturas, su cantidad, y arreglo. Esta última variable es importante porque está relacionada con el proceso de flujo de fluidos y con fenómenos como la deformación localizada. Frackita-v1 cubre la necesidad actual de un programa de análisis de fracturas en 1D para la enseñanza (educación), investigación o industria. \u0000El código usa datos del espaciamiento entre fracturas obtenidos mediante el método de líneas de muestreo en cualquier escala, desde una lámina delgada hasta mapas de lineamientos morfológicos. Adicionalmente, Frackita-v1 también genera distribuciones sintéticas de fracturas que ayudan a comprender mejor el uso de los parámetros calculados.","PeriodicalId":49601,"journal":{"name":"Revista Mexicana De Ciencias Geologicas","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2022-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48261337","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"La Unión Monzogranite: geochronology and significance of the Jurassic arc in the Sula Terrane, Guatemala","authors":"Francis Emanuel Salguero-Díaz, L. Solari, O. J. Vásquez, Ricardo Enrique Milián de la Cruz, C. Ortega-Obregón","doi":"10.22201/cgeo.20072902e.2022.2.1675","DOIUrl":"https://doi.org/10.22201/cgeo.20072902e.2022.2.1675","url":null,"abstract":"La Unión pluton (LUP) belongs to the metamorphic and igneous Sula Terrane (ST) of Central Guatemala, limited to the north by the Motagua fault (MF) and to the south by the Jocotán-Chamelecón fault system (J-CH-FS). The basement of the ST is characterized by the high-grade metamorphic rocks belonging to the Las Ovejas Complex and the extensive low-grade San Diego phyllite, the latter in tectonic contact with LUP. A combination of field data, petrographic and geochemical analyses as well as geochronologic dating by U-Pb method, allow to classify LUP as a monzogranite with an age of 170 Ma (average of two dated samples), characterized by high-K calcalkaline and peraluminous affinity and with a REE pattern typical of a continental magmatic arc. Some trace-elements behavior and a comparison of similar-age units found elsewhere in eastern, central and southern Mexico, allow to associate its formation to the lithospheric thinning and extension that occurred during the breakup of Pangea and the opening of the Gulf of Mexico.","PeriodicalId":49601,"journal":{"name":"Revista Mexicana De Ciencias Geologicas","volume":null,"pages":null},"PeriodicalIF":0.8,"publicationDate":"2022-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42528237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}