Pub Date : 2022-07-30DOI: 10.18268/bsgm2022v74n2a110522
Samuel Eguiluz y de Antuñano
El Bloque de Coahuila tiene rocas marinas y continentales del Paleozoico al Reciente que afloran en una vasta región del noreste de México. Este trabajo aporta datos de superficie y subsuelo que constatan la presencia del arco Nazas sobre este bloque. Se describen secciones estratigráficas que indican el proceso de transgresión marina sobre este bloque durante el Aptiano, así como el depósito de un potente espesor de caliza, dolomía y evaporita de edad Albiano y Cenomaniano temprano. La sucesión estratigráfica del Cretácico Superior está compuesta por el paso gradual entre las formaciones Indidura, Parras, Cerro del Pueblo, Cerro Huerta y capas La Soledad que representan depósitos de antepaís (foreland) con ~1000 m de espesor, estas rocas muestran una condensación estratigráfica al confrontar su espesor con secciones estratigráficas similares en las cuencas vecinas de Sabinas, del Centro de México y Chihuahua, las que tienen más de 2000 m de espesor de rocas de la misma edad. En este trabajo hay datos estructurales que se confrontan con ideas previas que consideraban una deformación tenue afectada por fallas de tipo normal. En el Bloque de Coahuila se distinguen tres estilos estructurales: uno está relacionado con pliegues de curvatura amplia, otro está formado por pliegues angostos y alargados, con fallas inversas, este estilo está restringido al borde austral del Bloque de Coahuila en dónde es traslapado tectónicamente por la napa de Parras, está napa sepulta las facies sedimentarias marginales pre-Aptiano de este bloque. Ambos estilos estructurales están estrechamente vinculados con la orientación de estructuras de la fase que deformó al Orógeno mexicano. El tercer estilo es representado por pliegues agudos y geométricamente escalonados, así como conjuntos estructurales con varios ejes burdamente orientados norte-sur, con vergencias opuestas y fallas diversas. Este último estilo estructural no tiene una componente de extensión o acortamiento definida y su deformación posiblemente es posterior a la fase que deformó el Orógeno mexicano. Los datos presentados definen la extensión geográfica del borde suroeste del Bloque de Coahuila.
科阿韦拉区块有古生代至近代的海陆岩石，它们出现在墨西哥东北部的大片地区。这项工作提供了地表和地下数据，以证实该区块上存在Nazas拱门。描述了地层剖面，这些剖面表明了阿普蒂安时期该区块的海侵过程，以及阿尔比安和塞诺曼尼亚早期强大厚度的石灰岩、白云石和蒸发岩的沉积。上白垩纪的地层演替是由Indidura地层、Parras地层、Cerro del Pueblo地层、Cerro Huerta地层和Layeras Soledad地层之间的逐步过渡组成的，这些地层代表厚度约为1000 m的前（前陆）矿床，这些岩石在厚度与邻近的萨比纳斯盆地、墨西哥中部和奇瓦瓦盆地的类似地层剖面相对时表现出地层浓缩，厚度超过2000米的岩石具有相同年龄。在这项工作中，有一些结构数据与以前认为受正常类型断层影响的微弱变形的想法相冲突。在科阿韦拉块体中，区分了三种构造样式：一种与宽曲率褶皱有关，另一种由窄而长的褶皱组成，有逆断层，这种样式仅限于科阿韦拉块体的南缘，在那里它被帕拉斯推覆构造叠加，纳帕埋葬了该块体的前阿普蒂安边缘沉积相。这两种结构风格都与墨西哥生态学家变形阶段结构的方向密切相关。第三种风格的代表是锐利的几何交错褶皱，以及具有多个南北方向的轴线的结构组合，具有相反的交汇处和不同的断层。后一种结构风格没有明确的伸展或缩短成分，其变形可能晚于墨西哥生态学家变形的阶段。所提供的数据定义了科阿韦拉区块西南缘的地理范围。
{"title":"Estratigrafía y evolución estructural del Bloque de Coahuila, noreste de México","authors":"Samuel Eguiluz y de Antuñano","doi":"10.18268/bsgm2022v74n2a110522","DOIUrl":"https://doi.org/10.18268/bsgm2022v74n2a110522","url":null,"abstract":"El Bloque de Coahuila tiene rocas marinas y continentales del Paleozoico al Reciente que afloran en una vasta región del noreste de México. Este trabajo aporta datos de superficie y subsuelo que constatan la presencia del arco Nazas sobre este bloque. Se describen secciones estratigráficas que indican el proceso de transgresión marina sobre este bloque durante el Aptiano, así como el depósito de un potente espesor de caliza, dolomía y evaporita de edad Albiano y Cenomaniano temprano. La sucesión estratigráfica del Cretácico Superior está compuesta por el paso gradual entre las formaciones Indidura, Parras, Cerro del Pueblo, Cerro Huerta y capas La Soledad que representan depósitos de antepaís (foreland) con ~1000 m de espesor, estas rocas muestran una condensación estratigráfica al confrontar su espesor con secciones estratigráficas similares en las cuencas vecinas de Sabinas, del Centro de México y Chihuahua, las que tienen más de 2000 m de espesor de rocas de la misma edad. En este trabajo hay datos estructurales que se confrontan con ideas previas que consideraban una deformación tenue afectada por fallas de tipo normal. En el Bloque de Coahuila se distinguen tres estilos estructurales: uno está relacionado con pliegues de curvatura amplia, otro está formado por pliegues angostos y alargados, con fallas inversas, este estilo está restringido al borde austral del Bloque de Coahuila en dónde es traslapado tectónicamente por la napa de Parras, está napa sepulta las facies sedimentarias marginales pre-Aptiano de este bloque. Ambos estilos estructurales están estrechamente vinculados con la orientación de estructuras de la fase que deformó al Orógeno mexicano. El tercer estilo es representado por pliegues agudos y geométricamente escalonados, así como conjuntos estructurales con varios ejes burdamente orientados norte-sur, con vergencias opuestas y fallas diversas. Este último estilo estructural no tiene una componente de extensión o acortamiento definida y su deformación posiblemente es posterior a la fase que deformó el Orógeno mexicano. Los datos presentados definen la extensión geográfica del borde suroeste del Bloque de Coahuila.","PeriodicalId":48849,"journal":{"name":"Boletin De La Sociedad Geologica Mexicana","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2022-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41485483","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}
Pub Date : 2022-07-30DOI: 10.18268/bsgm2022v74n2a070322
Gerardo Carbot-Chanona, L. Gómez-Pérez, Marco A. Coutiño-José
Eremotherium laurillardi was a common giant ground sloth in the Late Pleistocene of the Americas. A right femur referable to this species was recovered from fluvial sediments in Constitución 27 colony, Socoltenango municipality, in the southern State of Chiapas, Mexico. The femur shows the morphological characteristics of E. laurillardi, such as: large size; rectangular shape, it is dorsoventrally flattened; lateral and medial margin rectilinear and parallel, and patellar trochlea transversely elongated with the medial margin in the sagittal plane of the femur. The record from Constitución 27 town, adds a new locality for E. laurillardi in Mexico, which adds to the previously known seven localities with remains of this species in Chiapas. In Mexico, E. laurillardi is present in 31 localities distributed in 13 states, mainly in the central and southern portion of Mexico, with an altitudinal range between 0-200 up to 2000-2500 meters above sea level, indicating a mostly tropical distribution of this species.
{"title":"A new specimen of Eremotherium laurillardi (Xenarthra, Megatheriidae) from the Late Pleistocene of Chiapas, and comments about the distribution of the species in Mexico","authors":"Gerardo Carbot-Chanona, L. Gómez-Pérez, Marco A. Coutiño-José","doi":"10.18268/bsgm2022v74n2a070322","DOIUrl":"https://doi.org/10.18268/bsgm2022v74n2a070322","url":null,"abstract":"Eremotherium laurillardi was a common giant ground sloth in the Late Pleistocene of the Americas. A right femur referable to this species was recovered from fluvial sediments in Constitución 27 colony, Socoltenango municipality, in the southern State of Chiapas, Mexico. The femur shows the morphological characteristics of E. laurillardi, such as: large size; rectangular shape, it is dorsoventrally flattened; lateral and medial margin rectilinear and parallel, and patellar trochlea transversely elongated with the medial margin in the sagittal plane of the femur. The record from Constitución 27 town, adds a new locality for E. laurillardi in Mexico, which adds to the previously known seven localities with remains of this species in Chiapas. In Mexico, E. laurillardi is present in 31 localities distributed in 13 states, mainly in the central and southern portion of Mexico, with an altitudinal range between 0-200 up to 2000-2500 meters above sea level, indicating a mostly tropical distribution of this species.","PeriodicalId":48849,"journal":{"name":"Boletin De La Sociedad Geologica Mexicana","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2022-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47407789","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}
Pub Date : 2022-07-30DOI: 10.18268/bsgm2022v74n2a020122
Amir Hossein Rahiminejad, M. Yazdi, Amit K. Ghosh
In this paleoecological study we focused on coralline red algae-rich shoal grainstone facies in the Lower Miocene (Aquitanian) carbonates of the Qom Formation in the Vartun section in central Iran. The identified coralline red algae are mainly non-geniculate, although very rare geniculate forms of corallines were also recognized in thin section analysis. The identified algae are represented by Melobesioideae (Lithothamnion cf. valens, Lithothamnion cf. rovereoti, Lithothamnion cf. peleense, and Lithothamnion spp.), Mastophoroideae (Neogoniolithon sp., Spongites spp., and Spongites cf. fruticulosus), Sporolithon spp. (Sporolithon spp. and Sporolithon cf. airoldii), and geniculate coralline (Corallina). The algal taxa mainly display fruticose and lumpy growth forms. The dominance of the former is consistent with high water energy in the identified shoal environment. The presence of Lower Miocene algae indicates that deposition of carbonates took place in warm tropical to subtropical waters in a euphotic marine environment during the Aquitanian. Likewise, high water energy and sediment agitation resulted in taphonomic features such as fragmentation, abrasion, and disarticulation.
{"title":"Paleoecology of Lower Miocene coralline red algae-rich grainstone facies in the Qom Formation (Vartun section, central Iran)","authors":"Amir Hossein Rahiminejad, M. Yazdi, Amit K. Ghosh","doi":"10.18268/bsgm2022v74n2a020122","DOIUrl":"https://doi.org/10.18268/bsgm2022v74n2a020122","url":null,"abstract":"In this paleoecological study we focused on coralline red algae-rich shoal grainstone facies in the Lower Miocene (Aquitanian) carbonates of the Qom Formation in the Vartun section in central Iran. The identified coralline red algae are mainly non-geniculate, although very rare geniculate forms of corallines were also recognized in thin section analysis. The identified algae are represented by Melobesioideae (Lithothamnion cf. valens, Lithothamnion cf. rovereoti, Lithothamnion cf. peleense, and Lithothamnion spp.), Mastophoroideae (Neogoniolithon sp., Spongites spp., and Spongites cf. fruticulosus), Sporolithon spp. (Sporolithon spp. and Sporolithon cf. airoldii), and geniculate coralline (Corallina). The algal taxa mainly display fruticose and lumpy growth forms. The dominance of the former is consistent with high water energy in the identified shoal environment. The presence of Lower Miocene algae indicates that deposition of carbonates took place in warm tropical to subtropical waters in a euphotic marine environment during the Aquitanian. Likewise, high water energy and sediment agitation resulted in taphonomic features such as fragmentation, abrasion, and disarticulation.","PeriodicalId":48849,"journal":{"name":"Boletin De La Sociedad Geologica Mexicana","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2022-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43559840","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}
Pub Date : 2022-07-30DOI: 10.18268/bsgm2022v74n2a170222
Roger González-Herrera, Iván Cámara-Yamá, I. A. Sánchez y Pinto
La interacción del agua subterránea con el agua superficial es importante para estudiar los flujos tanto físicos como químicos en el ciclo hidrológico. Los sistemas de agua subterránea y agua superficial se han estudiado, por lo general, de manera separada, lo que dificulta la cuantificación de los flujos existentes entre ellos. Sin embargo, cada vez más se reconoce la importancia de entender cómo influye esta interfase en los balances hidrológicos, los ciclos geoquímicos, los ecosistemas y el cambio global. Para contribuir a este entendimiento, se llevó a cabo un estudio de la hidrodinámica regional de la zona de Los Ríos, Tabasco, México, en el que se siguió un enfoque de investigación de campo para estimar las interacciones entre el agua superficial y subterránea. El objetivo fue determinar la naturaleza actual de la interacción del agua subterránea con el agua superficial en la zona de estudio, enfocándose en la cuantificación del flujo de agua subterránea con base en información histórica. El análisis de los datos piezométricos indica que los gradientes hidráulicos son altos y sugiere tasas de recarga altas hacia los cuerpos de agua superficiales, incrementando significativamente el caudal de las corrientes. Se logró delimitar las zonas de recarga y descarga de aguas subterráneas utilizando una red de flujo.
{"title":"Hidrodinámica regional de Los Ríos, Tabasco, México","authors":"Roger González-Herrera, Iván Cámara-Yamá, I. A. Sánchez y Pinto","doi":"10.18268/bsgm2022v74n2a170222","DOIUrl":"https://doi.org/10.18268/bsgm2022v74n2a170222","url":null,"abstract":"La interacción del agua subterránea con el agua superficial es importante para estudiar los flujos tanto físicos como químicos en el ciclo hidrológico. Los sistemas de agua subterránea y agua superficial se han estudiado, por lo general, de manera separada, lo que dificulta la cuantificación de los flujos existentes entre ellos. Sin embargo, cada vez más se reconoce la importancia de entender cómo influye esta interfase en los balances hidrológicos, los ciclos geoquímicos, los ecosistemas y el cambio global. Para contribuir a este entendimiento, se llevó a cabo un estudio de la hidrodinámica regional de la zona de Los Ríos, Tabasco, México, en el que se siguió un enfoque de investigación de campo para estimar las interacciones entre el agua superficial y subterránea. El objetivo fue determinar la naturaleza actual de la interacción del agua subterránea con el agua superficial en la zona de estudio, enfocándose en la cuantificación del flujo de agua subterránea con base en información histórica. El análisis de los datos piezométricos indica que los gradientes hidráulicos son altos y sugiere tasas de recarga altas hacia los cuerpos de agua superficiales, incrementando significativamente el caudal de las corrientes. Se logró delimitar las zonas de recarga y descarga de aguas subterráneas utilizando una red de flujo.","PeriodicalId":48849,"journal":{"name":"Boletin De La Sociedad Geologica Mexicana","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2022-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48438185","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}
Pub Date : 2021-12-01DOI: 10.18268/bsgm2021v73n3a030121
G. Schweigert
A new monotypic genus and species of brachyurans, Petersbuchia thauckei n. gen. n. sp., is described from southern Germany. The holotype, an incompletely preserved carapace, was collected from a thick-bedded spongiolithic limestone of the Upper Jurassic Treuchtlingen Formation (early late Kimmeridgian, Acanthicum Zone). Petersbuchia adds to the diversification hotspot of early true crabs within the sponge-microbial magnafacies along the northern shelve of the Tethys Ocean in general and to the brachyuran fauna of the Treuchtlingen Formation in special.
{"title":"A new genus of prosopid crabs (Decapoda: Brachyura: Dromiacea) from the Upper Jurassic of southern Germany","authors":"G. Schweigert","doi":"10.18268/bsgm2021v73n3a030121","DOIUrl":"https://doi.org/10.18268/bsgm2021v73n3a030121","url":null,"abstract":"A new monotypic genus and species of brachyurans, Petersbuchia thauckei n. gen. n. sp., is described from southern Germany. The holotype, an incompletely preserved carapace, was collected from a thick-bedded spongiolithic limestone of the Upper Jurassic Treuchtlingen Formation (early late Kimmeridgian, Acanthicum Zone). Petersbuchia adds to the diversification hotspot of early true crabs within the sponge-microbial magnafacies along the northern shelve of the Tethys Ocean in general and to the brachyuran fauna of the Treuchtlingen Formation in special.","PeriodicalId":48849,"journal":{"name":"Boletin De La Sociedad Geologica Mexicana","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45258847","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}
Pub Date : 2021-12-01DOI: 10.18268/bsgm2021v73n3a240521
R. Gašparič, D. Tshudy, T. Chan, S. Ćorić
A new species of nephropid lobster, Metanephrops serendipitus sp. nov., is described from the lower Miocene (Ottnangian/Karpatian) in beds of Central Paratethys. Metanephrops serendipitus sp. nov. represents the first fossil representative of the genus from the northern hemisphere and thus extends its known palaeobiogeographical distribution. Additionally, the palaeoecology of the new species is discussed. Similar to extant species of Metanephrops, the fossil nephropid inhabited a fine-grained deep-sea environment, associated with frequent brittle stars.
{"title":"A new deepwater lobster, Metanephrops serendipitus sp. nov. (Crustacea, Decapoda, Nephropidae), from lower Miocene of Meljski hrib (Maribor, Slovenia)","authors":"R. Gašparič, D. Tshudy, T. Chan, S. Ćorić","doi":"10.18268/bsgm2021v73n3a240521","DOIUrl":"https://doi.org/10.18268/bsgm2021v73n3a240521","url":null,"abstract":"A new species of nephropid lobster, Metanephrops serendipitus sp. nov., is described from the lower Miocene (Ottnangian/Karpatian) in beds of Central Paratethys. Metanephrops serendipitus sp. nov. represents the first fossil representative of the genus from the northern hemisphere and thus extends its known palaeobiogeographical distribution. Additionally, the palaeoecology of the new species is discussed. Similar to extant species of Metanephrops, the fossil nephropid inhabited a fine-grained deep-sea environment, associated with frequent brittle stars.","PeriodicalId":48849,"journal":{"name":"Boletin De La Sociedad Geologica Mexicana","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46089354","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}
Pub Date : 2021-12-01DOI: 10.18268/bsgm2021v73n3a070121
F. Ferratges, P. Artal, S. Zamora
A new genus and two new species of fossil hermit crabs (Anomura, Paguroidea) are described from the southern Pyrenean basins (Huesca, NE Spain). Parapetrochirus nov. with P. robustus n. gen., n. sp., as type species, comes from the lower Eocene (Ypresian) Roda Formation. It preserves both chelipeds exhibiting a notable heterochely, a larger left cheliped and a concavity without granulation in the inner upper portions. Eocalcinus gerardbretoni n. sp. comes from the highest levels of the Arguis Formation (Priabonian) in Yeste locality. This species is characterized by a hemispherical outline and a sinuous lower margin of the chela, which differs from the type species of the genus. The cheliped morphology of such species allows inclusion in the families Diogenidae and Calcinidae, respectively. Fossil paguroids are relatively rare in the Eocene of Spain, therefore, the description of these two new taxa increases the known diversity of this group. Parapetrochirus robustus n. gen., n. sp. inhabited siliciclastic substrates within a prodelta environment and E. gerardbretoni n. sp. was collected from the last levels of coral rudstones just below the continental influence of Yeste-Arrés Formation.
{"title":"New hermit crabs (Paguroidea, Anomura) from the Eocene of Huesca, Spain","authors":"F. Ferratges, P. Artal, S. Zamora","doi":"10.18268/bsgm2021v73n3a070121","DOIUrl":"https://doi.org/10.18268/bsgm2021v73n3a070121","url":null,"abstract":"A new genus and two new species of fossil hermit crabs (Anomura, Paguroidea) are described from the southern Pyrenean basins (Huesca, NE Spain). Parapetrochirus nov. with P. robustus n. gen., n. sp., as type species, comes from the lower Eocene (Ypresian) Roda Formation. It preserves both chelipeds exhibiting a notable heterochely, a larger left cheliped and a concavity without granulation in the inner upper portions. Eocalcinus gerardbretoni n. sp. comes from the highest levels of the Arguis Formation (Priabonian) in Yeste locality. This species is characterized by a hemispherical outline and a sinuous lower margin of the chela, which differs from the type species of the genus. The cheliped morphology of such species allows inclusion in the families Diogenidae and Calcinidae, respectively. Fossil paguroids are relatively rare in the Eocene of Spain, therefore, the description of these two new taxa increases the known diversity of this group. Parapetrochirus robustus n. gen., n. sp. inhabited siliciclastic substrates within a prodelta environment and E. gerardbretoni n. sp. was collected from the last levels of coral rudstones just below the continental influence of Yeste-Arrés Formation.","PeriodicalId":48849,"journal":{"name":"Boletin De La Sociedad Geologica Mexicana","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41933083","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}
Pub Date : 2021-12-01DOI: 10.18268/bsgm2021v73n3p241121
D. Guinot, A. Garassino, F. Vega
Gérard Breton, born in Le Havre on 20 April 1944, brilliant scientist of international stature, associate paleontologist at Géosciences Rennes for many years, passed away on 3 April 2020. This special issue is dedicated to him as a tribute to his work and mastery, with a compilation of papers on some topics related to his ample research experience.
{"title":"A tribute to Gérard Breton (1944-2020)","authors":"D. Guinot, A. Garassino, F. Vega","doi":"10.18268/bsgm2021v73n3p241121","DOIUrl":"https://doi.org/10.18268/bsgm2021v73n3p241121","url":null,"abstract":"Gérard Breton, born in Le Havre on 20 April 1944, brilliant scientist of international stature, associate paleontologist at Géosciences Rennes for many years, passed away on 3 April 2020. This special issue is dedicated to him as a tribute to his work and mastery, with a compilation of papers on some topics related to his ample research experience.","PeriodicalId":48849,"journal":{"name":"Boletin De La Sociedad Geologica Mexicana","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42171044","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}
Pub Date : 2021-12-01DOI: 10.18268/bsgm2021v73n3a291220
Lucía A. González-López, M. Colín-García, A. Meléndez-López, J. Cruz-Castañeda, A. Negrón-Mendoza
Hydrothermal systems have been proposed as keen environments on the early Earth where chemical evolution processes could have occurred. The presence of minerals and a continuous energy flux stand out among the most remarkable conditions in such environments. In this research the decomposition of two organic acids was studied. Ionizing radiation and thermal energy were the sources selected for decomposition tests, as both are naturally present on hydrothermal systems and probably, they were present on early Earth. Radiation could come from unstable elements in minerals, and heat is the most abundant energy source in hydrothermal systems. As minerals play a key role in prebiotic chemistry experiments and are an essential component on hydrothermal environments, the role of olivine in decomposition was tested. Results indicate that both organic acids highly decomposed when irradiated or heated. Radiation is more efficient than heating in decomposing the carboxylic acids and forming other carboxylic acids. Interestingly, the occurrence of olivine affects decomposition on both heated and irradiated samples, as both the rate of decomposition, and the amount and type of products vary compared with experiments without the mineral. The formation of other carboxylic acids was followed in all samples. Succinic, tricarballilic, citric and carboxisuccinic acids were detected in radiolysis experiments of acetic acid. The radiolysis of formic acid produced oxalic and tartronic. The heating of acetic acid solutions formed succinic, tricarballilic, citric and carboxisuccinic acids. However, the heating of formic acids only generated oxalic acid. The presence of olivine affected the amount and type of carboxylic acids formed in radiation and heating experiments. Natural hydrothermal systems are complex environments and many variables are present in them. Our results reinforce the idea that a combination of variables is necessary to better simulate these environments in prebiotic chemistry experiments. All variables could have affected the prebiotic chemical reactions; and hence, the role of hydrothermal systems in prebiotic chemistry could be much more complex that thought.
{"title":"Prebiotic experiments simulating hydrothermal vents: Influence of olivine in the decomposition of simple carboxylic acids","authors":"Lucía A. González-López, M. Colín-García, A. Meléndez-López, J. Cruz-Castañeda, A. Negrón-Mendoza","doi":"10.18268/bsgm2021v73n3a291220","DOIUrl":"https://doi.org/10.18268/bsgm2021v73n3a291220","url":null,"abstract":"Hydrothermal systems have been proposed as keen environments on the early Earth where chemical evolution processes could have occurred. The presence of minerals and a continuous energy flux stand out among the most remarkable conditions in such environments. In this research the decomposition of two organic acids was studied. Ionizing radiation and thermal energy were the sources selected for decomposition tests, as both are naturally present on hydrothermal systems and probably, they were present on early Earth. Radiation could come from unstable elements in minerals, and heat is the most abundant energy source in hydrothermal systems. As minerals play a key role in prebiotic chemistry experiments and are an essential component on hydrothermal environments, the role of olivine in decomposition was tested. Results indicate that both organic acids highly decomposed when irradiated or heated. Radiation is more efficient than heating in decomposing the carboxylic acids and forming other carboxylic acids. Interestingly, the occurrence of olivine affects decomposition on both heated and irradiated samples, as both the rate of decomposition, and the amount and type of products vary compared with experiments without the mineral. The formation of other carboxylic acids was followed in all samples. Succinic, tricarballilic, citric and carboxisuccinic acids were detected in radiolysis experiments of acetic acid. The radiolysis of formic acid produced oxalic and tartronic. The heating of acetic acid solutions formed succinic, tricarballilic, citric and carboxisuccinic acids. However, the heating of formic acids only generated oxalic acid. The presence of olivine affected the amount and type of carboxylic acids formed in radiation and heating experiments. Natural hydrothermal systems are complex environments and many variables are present in them. Our results reinforce the idea that a combination of variables is necessary to better simulate these environments in prebiotic chemistry experiments. All variables could have affected the prebiotic chemical reactions; and hence, the role of hydrothermal systems in prebiotic chemistry could be much more complex that thought.","PeriodicalId":48849,"journal":{"name":"Boletin De La Sociedad Geologica Mexicana","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44178625","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}
Pub Date : 2021-12-01DOI: 10.18268/bsgm2021v73n3a261220
A. Garassino, Giovanni Pasini, Don Clements
A new spider crab, Eoinachoides bretoni n. sp. (Epialtidae MacLeay, 1838) from the Comfort Member of the Castle Hayne Formation (Eocene) of Onslow County, North Carolina (USA), is herein described, representing the second spider crab recovered from this member. Although the new species does not enlarge the stratigraphical range for the genus which is currently restricted from the Eocene to Miocene, it is the first report in North America, extending the palaeogeographic distribution of Eoinachoides, limited currently in the fossil record of South America. In addition, an updated list of the species of the Castle Hayne Formation is herein provided.
{"title":"A new spider crab (Brachyura, Epialtidae) from the Castle Hayne Limestone Formation (Eocene), North Carolina, USA","authors":"A. Garassino, Giovanni Pasini, Don Clements","doi":"10.18268/bsgm2021v73n3a261220","DOIUrl":"https://doi.org/10.18268/bsgm2021v73n3a261220","url":null,"abstract":"A new spider crab, Eoinachoides bretoni n. sp. (Epialtidae MacLeay, 1838) from the Comfort Member of the Castle Hayne Formation (Eocene) of Onslow County, North Carolina (USA), is herein described, representing the second spider crab recovered from this member. Although the new species does not enlarge the stratigraphical range for the genus which is currently restricted from the Eocene to Miocene, it is the first report in North America, extending the palaeogeographic distribution of Eoinachoides, limited currently in the fossil record of South America. In addition, an updated list of the species of the Castle Hayne Formation is herein provided.","PeriodicalId":48849,"journal":{"name":"Boletin De La Sociedad Geologica Mexicana","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45510047","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}
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