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Papers by Juan Carlos Gutiérrez-Marco

Geogaceta

Se presenta el tercer ejemplar del trilobites asáfido Megistaspis (Ekeraspis) cf. hammondi con co... more Se presenta el tercer ejemplar del trilobites asáfido Megistaspis (Ekeraspis) cf. hammondi con conservación excepcional de apéndices, procedente del Fossil-Lagerstätte ordovícico de tipo Burgess Shale más importante del mundo, localizado en Marruecos. Los trilobites con apéndices o partes blandas se detectan en niveles del Tremadociense superior dentro de la Formación de Fezouata, pero son fósiles muy raros. El ejemplar estudiado conserva la antena derecha y nueve apéndices situados bajo el exoesqueleto, localizados en la parte derecha del cuerpo. Se trata principalmente de endópodos, pero al menos en dos apéndices se reconocen partes de los exópodos porque conservan sus largas lamelas. El primer endópodo parece corresponder al extremo distal del tercer apéndice cefálico, y el resto son apéndices torácicos. Las antenas observadas en ejemplares comerciales de la misma especie suelen estar manipuladas por los preparadores y son poco fiables. Además del asáfido estudiado, la conservaci...

Geological Society, London, Special Publications, 2022

Cornute stylophorans are a minor, although typical, component of Middle–Late Ordovician echinoder... more Cornute stylophorans are a minor, although typical, component of Middle–Late Ordovician echinoderm assemblages adapted to soft siliciclastic substrates in high-latitude peri-Gondwanan regions. All previously reported occurrences of Darriwilian–Katian cornutes from the Czech Republic, France, Morocco and Spain are revised and their plate homologies reassessed. The genera Beryllia and Juliaecarpus are reinterpreted as junior synonyms of Domfrontia , and Thoralicystis is synonymized with Bohemiaecystis . Several Mediterranean scotiaecystids previously assigned to Bohemiaecystis and/or Scotiaecystis are placed within Thoralicarpus gen. nov., and cornute taxa originally left in open nomenclature by Chauvel are formally described as Bohemiaecystis chouberti sp. nov. (AVI) and Destombesicarpus izegguirenensis gen. et sp. nov. (AVIII). Other new Mediterranean taxa include Arauricystis clariondi sp. nov., Destombesicarpus budili gen. et sp. nov., Milonicystis reboulorum sp. nov., Thoralicarp...

Gondwana Research, 2021

Abstract In the Eastern Cordillera of Peru, observations related to the accretion of the Arequipa... more Abstract In the Eastern Cordillera of Peru, observations related to the accretion of the Arequipa Terrane to the Amazon craton are scarce and reactivation of sutures in a backarc basin may make interpretation more difficult. Cambro-Ordovician backarc successions located in proximity to a proposed suture in the Eastern Cordillera of southern Peru were investigated at Umachiri and Ollantaytambo in order to disentangle the early Paleozoic tectonic history of the Arequipa Terrane. At Umachiri, newly identified fossil assemblages in the upper Cambrian Llallahue Formation (Fm) and in the Lower to Middle Ordovician Umachiri Fm constrain the age of these successions and allow correlation of these strata throughout the Central Andes. Using U–Pb geochronology on zircon, we establish that the Ollantaytambo Fm is an upper Carboniferous succession and that the Umachiri Fm instead correlates with the Lower to Middle Ordovician Veronica and San Jose formations, which form the base of a backarc succession in the Eastern Cordillera of southern Peru that extended into northwestern Argentina. Detrital zircons from the Umachiri Fm display age signatures characteristic of Arequipa basement and contain a prominent 540–510 Ma peak. Precise dating and trace element analysis yielded 539 Ma arc-derived and 522–510 Ma mantle-derived zircons. We infer that a Cambrian backarc system related to deposition of the lower Furongian (~494 Ma) Llallahue Fm developed following ~ 540 Ma Pampean arc magmatism. Closure of the backarc in late Cambrian to Early Ordovician time resulted in regional deformation, uplift, and erosion followed by renewed backarc subsidence in the Ordovician Period. In summary, our results support a new tectonic model of late Neoproterozoic to early Cambrian Pampean collision of an exotic Arequipa Terrane with Amazonia, opening and closing of a Cambrian backarc basin, the presence of parallel Ordovician continental arcs associated with Famatinian subduction, and the opening of an Ordovician–Devonian backarc basin.

Fossils and Strata Series, 2019

Este articulo es una contribucion a los proyectos IBEROR (CGL2012-39471) y PICG 653 de la IUGS-UN... more Este articulo es una contribucion a los proyectos IBEROR (CGL2012-39471) y PICG 653 de la IUGS-UNESCO.

IOP Conference Series: Earth and Environmental Science, 2019

Zircon and monazite ID-TIMS U-Pb dating of four Lower Ordovician altered ash-fall tuff beds (K-Be... more Zircon and monazite ID-TIMS U-Pb dating of four Lower Ordovician altered ash-fall tuff beds (K-Bentonites) in NW Iberia provided coetaneous ages of 477.5±1, 477±1.3 Ma, 477.2±1.1 Ma and 477.3±1 Ma, with a pooled concordia age of 477.2±0.74 Ma. A conservative estimation of the volume and mass of the studied K-bentonite beds (using data from the Cantabrian Zone) returns a minimum volume for the preserved deposits of ca. 37.5 km3 (Volcanic Explosivity Index - VEI = 6, Colossal). When considering other putative equivalent beds in other parts of Iberia and neighbouring realms the volume of ejecta associated to this event would make it reach the Supervolcanic-Apocalyptic status (VEI=8, >1000 km3). Contrary to most cases of this kind of gargantuan eruption events, the studied magmatic event took place in relation to continental margin extension and thinning and not to plate convergence. We speculate that a geochronologically coincident large caldera event observed in the geological reco...

Geological Society, London, Special Publications, 2019

The Anti-Atlas contains a thick, volcanic-free Ordovician succession that originally deposited in... more The Anti-Atlas contains a thick, volcanic-free Ordovician succession that originally deposited in a passive-margin basin. Three main sedimentary packages are bounded by major unconformities: (i) the Tremadocian–Floian Lower Fezouata and Upper Fezouata formations, which unconformably overlie a palaeorelief of Cambrian rifting volcanosedimentary complexes, and are subsequently topped by a Dapingian paraconformable gap; (ii) the Darriwilian–Katian Tachilla Formation and First Bani and Ktaoua groups, the latter unconformably overlain by a Hirnantian glaciogenic succession; and (iii) the Second Bani Group, which subsequently infilled the former glaciogenic palaeorelief. Due to the scarcity of carbonate interbeds for etching analyses, leading to rare references of conodonts, the global Ordovician chart is interpolated on the basis of microphytoplancton (acritarchs and chitinozoans), regional graptolites and brachiopods. The Ordovician counter-clockwise rotation of Gondwana led its Morocca...

Journal of African Earth Sciences, 2018

Scientific Reports, 2017

Trilobites were one of the most successful groups of marine arthropods during the Palaeozoic era,... more Trilobites were one of the most successful groups of marine arthropods during the Palaeozoic era, yet their soft-part anatomy is only known from a few exceptionally-preserved specimens found in a handful of localities from the Cambrian to the Devonian. This is because, even if the sclerotized appendages were not destroyed during early taphonomic stages, they are often overprinted by the three-dimensional, mineralised exoskeleton. Inferences about the ventral anatomy and behavioural activities of trilobites can also be derived from the ichnological record, which suggests that mostCruzianaandRusophycustrace fossils were possibly produced by the actions of trilobites. Three specimens of the asaphid trilobiteMegistaspis (Ekeraspis) hammondi, have been discovered in the Lower Ordovician Fezouata Konservat-Lagerstätte of southern Morocco, preserving appendages and digestive tract. The digestive structures include a crop with digestive caeca, while the appendages display exopodal setae and...

Palaeogeography, Palaeoclimatology, Palaeoecology, 2016

Bulletin of Geosciences, 2016

Palaeontology, 2015

A Sandbian brachiopod association from the Calapuja Formation, in the Peruvian Altiplano, north‐w... more A Sandbian brachiopod association from the Calapuja Formation, in the Peruvian Altiplano, north‐west of Lake Titicaca, has allowed a re‐examination of the palaeobiogeographical relationships between Gondwana and Avalonia during the Late Ordovician, when the palaeocontinents are considered to be already very distant from one another. The brachiopod fauna includes the new species Onnizetina calapujensis sp. nov., Horderleyella chacaltanai sp. nov., Drabovinella minuscula sp. nov. and Tasmanella curtiseptata sp. nov., as well as Caeroplecia sp., Dinorthis cf. flabellulum and Tunariorthis cardocanalis. In addition, Colaptomena expansa expansa and Heterorthis retrorsistria, known from the British Burrellian Stage of the Caradoc Series (late Sandbian) in Wales and the Welsh Borderlands, have also been identified. The brachiopod collection is the most diverse known from a single locality in the whole Central Andean Basin. Within it, forms with clear Gondwanan links occur, such as the new s...

Juan C. Gutiérrez-Marco, Artur A. Sá, Diego C. García-Bellido, and Isabel Rában

The Evolution of the Rheic Ocean: From Avalonian-Cadomian Active Margin to Alleghenian-Variscan Collision, 2007

ABSTRACT Zircons from a&a... more ABSTRACT Zircons from a> 45-cm-thick K-bentonite (altered ash-fall tuff) bed within the upper Barrios Formation (Ordovician Armorican Quartzite facies), in the Cantabrian zone of the Iberian Variscan belt were dated by isotope dilution–thermal ionization mass spectrometry. U-Pb analyses of six highly abraded single grains yielded concordant and overlapping error ellipses with a pooled concordia age of 477.47±0.93 Ma. This age provides the depositional age of the Armorican Quartzite facies in the studied sector and ...

Bulletin of Geosciences, 2013

Review of Palaeobotany and Palynology, 2006

A single sample from the La Matosa Member of the Barrios Formation, exposed during the excavation... more A single sample from the La Matosa Member of the Barrios Formation, exposed during the excavation of the El Fabar Tunnel in Asturias, N Spain, yielded a rich and well-preserved Late Cambrian acritarch assemblage. The Middle? to Upper Cambrian La Matosa ...

Geogaceta

Se presenta el tercer ejemplar del trilobites asáfido Megistaspis (Ekeraspis) cf. hammondi con co... more Se presenta el tercer ejemplar del trilobites asáfido Megistaspis (Ekeraspis) cf. hammondi con conservación excepcional de apéndices, procedente del Fossil-Lagerstätte ordovícico de tipo Burgess Shale más importante del mundo, localizado en Marruecos. Los trilobites con apéndices o partes blandas se detectan en niveles del Tremadociense superior dentro de la Formación de Fezouata, pero son fósiles muy raros. El ejemplar estudiado conserva la antena derecha y nueve apéndices situados bajo el exoesqueleto, localizados en la parte derecha del cuerpo. Se trata principalmente de endópodos, pero al menos en dos apéndices se reconocen partes de los exópodos porque conservan sus largas lamelas. El primer endópodo parece corresponder al extremo distal del tercer apéndice cefálico, y el resto son apéndices torácicos. Las antenas observadas en ejemplares comerciales de la misma especie suelen estar manipuladas por los preparadores y son poco fiables. Además del asáfido estudiado, la conservaci...

Geological Society, London, Special Publications, 2022

Cornute stylophorans are a minor, although typical, component of Middle–Late Ordovician echinoder... more Cornute stylophorans are a minor, although typical, component of Middle–Late Ordovician echinoderm assemblages adapted to soft siliciclastic substrates in high-latitude peri-Gondwanan regions. All previously reported occurrences of Darriwilian–Katian cornutes from the Czech Republic, France, Morocco and Spain are revised and their plate homologies reassessed. The genera Beryllia and Juliaecarpus are reinterpreted as junior synonyms of Domfrontia , and Thoralicystis is synonymized with Bohemiaecystis . Several Mediterranean scotiaecystids previously assigned to Bohemiaecystis and/or Scotiaecystis are placed within Thoralicarpus gen. nov., and cornute taxa originally left in open nomenclature by Chauvel are formally described as Bohemiaecystis chouberti sp. nov. (AVI) and Destombesicarpus izegguirenensis gen. et sp. nov. (AVIII). Other new Mediterranean taxa include Arauricystis clariondi sp. nov., Destombesicarpus budili gen. et sp. nov., Milonicystis reboulorum sp. nov., Thoralicarp...

Gondwana Research, 2021

Abstract In the Eastern Cordillera of Peru, observations related to the accretion of the Arequipa... more Abstract In the Eastern Cordillera of Peru, observations related to the accretion of the Arequipa Terrane to the Amazon craton are scarce and reactivation of sutures in a backarc basin may make interpretation more difficult. Cambro-Ordovician backarc successions located in proximity to a proposed suture in the Eastern Cordillera of southern Peru were investigated at Umachiri and Ollantaytambo in order to disentangle the early Paleozoic tectonic history of the Arequipa Terrane. At Umachiri, newly identified fossil assemblages in the upper Cambrian Llallahue Formation (Fm) and in the Lower to Middle Ordovician Umachiri Fm constrain the age of these successions and allow correlation of these strata throughout the Central Andes. Using U–Pb geochronology on zircon, we establish that the Ollantaytambo Fm is an upper Carboniferous succession and that the Umachiri Fm instead correlates with the Lower to Middle Ordovician Veronica and San Jose formations, which form the base of a backarc succession in the Eastern Cordillera of southern Peru that extended into northwestern Argentina. Detrital zircons from the Umachiri Fm display age signatures characteristic of Arequipa basement and contain a prominent 540–510 Ma peak. Precise dating and trace element analysis yielded 539 Ma arc-derived and 522–510 Ma mantle-derived zircons. We infer that a Cambrian backarc system related to deposition of the lower Furongian (~494 Ma) Llallahue Fm developed following ~ 540 Ma Pampean arc magmatism. Closure of the backarc in late Cambrian to Early Ordovician time resulted in regional deformation, uplift, and erosion followed by renewed backarc subsidence in the Ordovician Period. In summary, our results support a new tectonic model of late Neoproterozoic to early Cambrian Pampean collision of an exotic Arequipa Terrane with Amazonia, opening and closing of a Cambrian backarc basin, the presence of parallel Ordovician continental arcs associated with Famatinian subduction, and the opening of an Ordovician–Devonian backarc basin.

Fossils and Strata Series, 2019

Este articulo es una contribucion a los proyectos IBEROR (CGL2012-39471) y PICG 653 de la IUGS-UN... more Este articulo es una contribucion a los proyectos IBEROR (CGL2012-39471) y PICG 653 de la IUGS-UNESCO.

IOP Conference Series: Earth and Environmental Science, 2019

Zircon and monazite ID-TIMS U-Pb dating of four Lower Ordovician altered ash-fall tuff beds (K-Be... more Zircon and monazite ID-TIMS U-Pb dating of four Lower Ordovician altered ash-fall tuff beds (K-Bentonites) in NW Iberia provided coetaneous ages of 477.5±1, 477±1.3 Ma, 477.2±1.1 Ma and 477.3±1 Ma, with a pooled concordia age of 477.2±0.74 Ma. A conservative estimation of the volume and mass of the studied K-bentonite beds (using data from the Cantabrian Zone) returns a minimum volume for the preserved deposits of ca. 37.5 km3 (Volcanic Explosivity Index - VEI = 6, Colossal). When considering other putative equivalent beds in other parts of Iberia and neighbouring realms the volume of ejecta associated to this event would make it reach the Supervolcanic-Apocalyptic status (VEI=8, >1000 km3). Contrary to most cases of this kind of gargantuan eruption events, the studied magmatic event took place in relation to continental margin extension and thinning and not to plate convergence. We speculate that a geochronologically coincident large caldera event observed in the geological reco...

Geological Society, London, Special Publications, 2019

The Anti-Atlas contains a thick, volcanic-free Ordovician succession that originally deposited in... more The Anti-Atlas contains a thick, volcanic-free Ordovician succession that originally deposited in a passive-margin basin. Three main sedimentary packages are bounded by major unconformities: (i) the Tremadocian–Floian Lower Fezouata and Upper Fezouata formations, which unconformably overlie a palaeorelief of Cambrian rifting volcanosedimentary complexes, and are subsequently topped by a Dapingian paraconformable gap; (ii) the Darriwilian–Katian Tachilla Formation and First Bani and Ktaoua groups, the latter unconformably overlain by a Hirnantian glaciogenic succession; and (iii) the Second Bani Group, which subsequently infilled the former glaciogenic palaeorelief. Due to the scarcity of carbonate interbeds for etching analyses, leading to rare references of conodonts, the global Ordovician chart is interpolated on the basis of microphytoplancton (acritarchs and chitinozoans), regional graptolites and brachiopods. The Ordovician counter-clockwise rotation of Gondwana led its Morocca...

Journal of African Earth Sciences, 2018

Scientific Reports, 2017

Trilobites were one of the most successful groups of marine arthropods during the Palaeozoic era,... more Trilobites were one of the most successful groups of marine arthropods during the Palaeozoic era, yet their soft-part anatomy is only known from a few exceptionally-preserved specimens found in a handful of localities from the Cambrian to the Devonian. This is because, even if the sclerotized appendages were not destroyed during early taphonomic stages, they are often overprinted by the three-dimensional, mineralised exoskeleton. Inferences about the ventral anatomy and behavioural activities of trilobites can also be derived from the ichnological record, which suggests that mostCruzianaandRusophycustrace fossils were possibly produced by the actions of trilobites. Three specimens of the asaphid trilobiteMegistaspis (Ekeraspis) hammondi, have been discovered in the Lower Ordovician Fezouata Konservat-Lagerstätte of southern Morocco, preserving appendages and digestive tract. The digestive structures include a crop with digestive caeca, while the appendages display exopodal setae and...

Palaeogeography, Palaeoclimatology, Palaeoecology, 2016

Bulletin of Geosciences, 2016

Palaeontology, 2015

A Sandbian brachiopod association from the Calapuja Formation, in the Peruvian Altiplano, north‐w... more A Sandbian brachiopod association from the Calapuja Formation, in the Peruvian Altiplano, north‐west of Lake Titicaca, has allowed a re‐examination of the palaeobiogeographical relationships between Gondwana and Avalonia during the Late Ordovician, when the palaeocontinents are considered to be already very distant from one another. The brachiopod fauna includes the new species Onnizetina calapujensis sp. nov., Horderleyella chacaltanai sp. nov., Drabovinella minuscula sp. nov. and Tasmanella curtiseptata sp. nov., as well as Caeroplecia sp., Dinorthis cf. flabellulum and Tunariorthis cardocanalis. In addition, Colaptomena expansa expansa and Heterorthis retrorsistria, known from the British Burrellian Stage of the Caradoc Series (late Sandbian) in Wales and the Welsh Borderlands, have also been identified. The brachiopod collection is the most diverse known from a single locality in the whole Central Andean Basin. Within it, forms with clear Gondwanan links occur, such as the new s...

Juan C. Gutiérrez-Marco, Artur A. Sá, Diego C. García-Bellido, and Isabel Rában

The Evolution of the Rheic Ocean: From Avalonian-Cadomian Active Margin to Alleghenian-Variscan Collision, 2007

ABSTRACT Zircons from a&a... more ABSTRACT Zircons from a> 45-cm-thick K-bentonite (altered ash-fall tuff) bed within the upper Barrios Formation (Ordovician Armorican Quartzite facies), in the Cantabrian zone of the Iberian Variscan belt were dated by isotope dilution–thermal ionization mass spectrometry. U-Pb analyses of six highly abraded single grains yielded concordant and overlapping error ellipses with a pooled concordia age of 477.47±0.93 Ma. This age provides the depositional age of the Armorican Quartzite facies in the studied sector and ...

Bulletin of Geosciences, 2013

Review of Palaeobotany and Palynology, 2006

A single sample from the La Matosa Member of the Barrios Formation, exposed during the excavation... more A single sample from the La Matosa Member of the Barrios Formation, exposed during the excavation of the El Fabar Tunnel in Asturias, N Spain, yielded a rich and well-preserved Late Cambrian acritarch assemblage. The Middle? to Upper Cambrian La Matosa ...

Spanish translation (Castellano, Old-World) of ICS International Chronostratigraphic Chart 2015/0... more Spanish translation (Castellano, Old-World) of ICS International Chronostratigraphic Chart 2015/01. IUGS ICS. Translation by J.C. Gutiérrez-Marco et al.

La definición del Estratotipo Global de Límite (GSSP - Global Boundary Stratotype Section and Point) para la base de los diversos pisos, series, sistemas y eratemas, es un proceso que aún no ha sido completado. Tampoco para los estratotipos de límite de las unidades del Arcaico y Proterozoico, cuya división inicial se fundamentó en una convención de edades absolutas (GSSA - Global Standard Stratigraphic Ages). Los GSSP oficiales se marcan con el símbolo del “Clavo Dorado” (Golden Spike), que también los materializa en el terreno.

El original de la Tabla, más los detalles de los GSSP (criterio de definición de cada uno, localización geográfica y geológica, correlación, etc.), se actualiza regularmente en la web: http://www.stratigraphy.org.

La datación absoluta en millones de años (Ma) para la base del Ediacárico y del resto de unidades del Fanerozoico, es sólo orientativa, en especial para aquellos límites sin GSSP formal (~Ma). Estos números podrán revisarse en el futuro o recalibrarse geocronométricamente. Los valores indicados provienen de Gradstein et al. (A Geologic Time Scale 2012), exceptuando las dataciones del Pleistoceno, Pérmico, Triásico y Cretácico, aportadas por las subcomisiones respectivas de la ICS-IUGS.

Traducción al castellano de J.C. Gutiérrez-Marco en colaboración con: Sociedad Geológica de España, Instituto Geológico y Minero de España, Instituto de Geociencias (CSIC-UCM) y Real Academia de Ciencias. Tabla diseñada por K.M. Cohen, S.C. Finney y P.L. Gibbard. © International Commission on Stratigraphy (IUGS) 2015