Journal articles: 'Ecuadorian margin'

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Lynner, Colton, Clinton Koch, Susan L. Beck, Anne Meltzer, Lillian Soto-Cordero, Mariah C. Hoskins, Josh C. Stachnik, et al. "Upper-plate structure in Ecuador coincident with the subduction of the Carnegie Ridge and the southern extent of large mega-thrust earthquakes." Geophysical Journal International 220, no. 3 (December 17, 2019): 1965–77. http://dx.doi.org/10.1093/gji/ggz558.

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SUMMARY The Ecuadorian convergent margin has experienced many large mega-thrust earthquakes in the past century, beginning with a 1906 event that propagated along as much as 500 km of the plate interface. Many subsections of the 1906 rupture area have subsequently produced Mw ≥ 7.7 events, culminating in the 16 April 2016, Mw 7.8 Pedernales earthquake. Interestingly, no large historic events Mw ≥ 7.7 appear to have propagated southward of ∼1°S, which coincides with the subduction of the Carnegie Ridge. We combine data from temporary seismic stations deployed following the Pedernales earthquake with data recorded by the permanent stations of the Ecuadorian national seismic network to discern the velocity structure of the Ecuadorian forearc and Cordillera using ambient noise tomography. Ambient noise tomography extracts Vsv information from the ambient noise wavefield and provides detailed constraints on velocity structures in the crust and upper mantle. In the upper 10 km of the Ecuadorian forearc, we see evidence of the deepest portions of the sedimentary basins in the region, the Progreso and Manabí basins. At depths below 30 km, we observe a sharp delineation between accreted fast forearc terranes and the thick crust of the Ecuadorian Andes. At depths ∼20 km, we see a strong fast velocity anomaly that coincides with the subducting Carnegie Ridge as well as the southern boundary of large mega-thrust earthquakes. Our observations raise the possibility that upper-plate structure, in addition to the subducting Carnegie Ridge, plays a role in the large event segmentation seen along the Ecuadorian margin.

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Van Melle, Jeremie, Washinton Vilema, Bastien Faure-Brac, Martha Ordoñez, Henriette Lapierre, Nelson Jimenez, Etienne Jaillard, and Milton Garcia. "Pre-collision evolution of the Piñón oceanic terrane of SW Ecuador: stratigraphy and geochemistry of the “Calentura Formation”." Bulletin de la Société Géologique de France 179, no. 5 (September 1, 2008): 433–43. http://dx.doi.org/10.2113/gssgfbull.179.5.433.

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Abstract The stratigraphic revision of the southern coastal Ecuadorian series makes possible the reconstruction of the pre-collision history of the Caribbean plateau accreted to the Ecuadorian margin. The Coniacian age of the oceanic basement (Piñón Fm) indicates that the latter is part of the Caribbean oceanic plateau. It is overlain by the Calentura Fm, which comprises from base to top: (i) 20 to 200 m of lavas and volcanic breccias of arc affinity (Las Orquídeas Mb), (ii) siliceous, organic rich black limestones of (middle?) Coniacian age, (iii) red, radiolarian rich, calcareous cherts ascribed to the Santonian-early Campanian, and (iv) marls, greywackes and island arc tuffs of Mid Campanian age. The latter are overlain by volcaniclastic turbidites of Mid to Late Campanian age (Cayo Fm), coeval to the Campanian-Maastrichtian island arc series locate farther west (San Lorenzo Fm). The Las Orquídeas magmatic unit is interpreted as resulting from the melting of the Caribbean plateau, rather than from an ephemeral subduction process. The transition from coniacian limestones to santonian red cherts would be related to the thermal subsidence of the Caribbean plateau. The uplift of the latter and the development of the San Lorenzo island arc in the Middle Campanian would be due to the collision of the Caribbean plateau with the Mexican margin. Early in the Late Maastrichtian, the collision of the Caribbean plateau with the Ecuadorian margin would have triggered the cessation of the San Lorenzo arc activity. In the Late Paleocene, the Caribbean plateau was split into two terranes: the western Piñón terrane, which collided with the eastern Guaranda terrane.

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VÉLEZ-ABARCA, LEISBERTH, GABRIEL A. ITURRALDE, HENRY X. GARZÓN, DIEGO GUTIÉRREZ DEL POZO, and LUIS E. BAQUERO. "A new species of the genus Octomeria (Orchidaceae: Pleurothallidinae) from Ecuador." Phytotaxa 637, no. 1 (February 15, 2024): 106–12. http://dx.doi.org/10.11646/phytotaxa.637.1.8.

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A new species of Octomeria was found during an orchid research expedition in the southern Ecuadorian Amazon. Octomeria jimenezii is described and illustrated, and information on its distribution, habitat and conservation status is provided. The newly proposed taxon is morphologically similar to O. pacii, from which it differs by the lower lateral lobes, with an obtuse to subacute angle to the anterior margin.

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Bethoux, Nicole, Monica Segovia, Viviana Alvarez, Jean-Yves Collot, Philippe Charvis, Audrey Gailler, and Tony Monfret. "Seismological study of the central Ecuadorian margin: Evidence of upper plate deformation." Journal of South American Earth Sciences 31, no. 1 (February 2011): 139–52. http://dx.doi.org/10.1016/j.jsames.2010.08.001.

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Bourdon, Erwan, Jean-Philippe Eissen, Marc-André Gutscher, Michel Monzier, Minard L. Hall, and Joseph Cotten. "Magmatic response to early aseismic ridge subduction: the Ecuadorian margin case (South America)." Earth and Planetary Science Letters 205, no. 3-4 (January 2003): 123–38. http://dx.doi.org/10.1016/s0012-821x(02)01024-5.

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Tamay, José, Jesús Galindo-Zaldivar, John Soto, and Antonio J. Gil. "GNSS Constraints to Active Tectonic Deformations of the South American Continental Margin in Ecuador." Sensors 21, no. 12 (June 10, 2021): 4003. http://dx.doi.org/10.3390/s21124003.

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GNSS observations constitute the main tool to reveal Earth’s crustal deformations in order to improve the identification of geological hazards. The Ecuadorian Andes were formed by Nazca Plate subduction below the Pacific margin of the South American Plate. Active tectonic-related deformation continues to present, and it is constrained by 135 GPS stations of the RENAGE and REGME deployed by the IGM in Ecuador (1995.4–2011.0). They show a regional ENE displacement, increasing towards the N, of the deformed North Andean Sliver in respect to the South American Plate and Inca Sliver relatively stable areas. The heterogeneous displacements towards the NNE of the North Andean Sliver are interpreted as consequences of the coupling of the Carnegie Ridge in the subduction zone. The Dolores–Guayaquil megashear constitutes its southeastern boundary and includes the dextral to normal transfer Pallatanga fault, that develops the Guayaquil Gulf. This fault extends northeastward along the central part of the Cordillera Real, in relay with the reverse dextral Cosanga–Chingual fault and finally followed by the reverse dextral Sub-Andean fault zone. While the Ecuadorian margin and Andes is affected by ENE–WSW shortening, the easternmost Manabí Basin located in between the Cordillera Costanera and the Cordillera Occidental of the Andes, underwent moderate ENE–WSW extension and constitutes an active fore-arc basin of the Nazca plate subduction. The integration of the GPS and seismic data evidences that highest rates of deformation and the highest tectonic hazards in Ecuador are linked: to the subduction zone located in the coastal area; to the Pallatanga transfer fault; and to the Eastern Andes Sub-Andean faults.

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Koch, Clinton D., Colton Lynner, Jonathan Delph, Susan L. Beck, Anne Meltzer, Yvonne Font, Lillian Soto-Cordero, et al. "Structure of the Ecuadorian forearc from the joint inversion of receiver functions and ambient noise surface waves." Geophysical Journal International 222, no. 3 (May 15, 2020): 1671–85. http://dx.doi.org/10.1093/gji/ggaa237.

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SUMMARY The Ecuadorian forearc is a complex region of accreted terranes with a history of large megathrust earthquakes. Most recently, a Mw 7.8 megathrust earthquake ruptured the plate boundary offshore of Pedernales, Ecuador on 16 April 2016. Following this event, an international collaboration arranged by the Instituto Geofisico at the Escuela Politécnica Nacional mobilized a rapid deployment of 65 seismic instruments along the Ecuadorian forearc. We combine this new seismic data set with 14 permanent stations from the Ecuadorian national network to better understand how variations in crustal structure relate to regional seismic hazards along the margin. Here, we present receiver function adaptive common conversion point stacks and a shear velocity model derived from the joint inversion of receiver functions and surface wave dispersion data obtained through ambient noise cross-correlations for the upper 50 km of the forearc. Beneath the forearc crust, we observe an eastward dipping slow velocity anomaly we interpret as subducting oceanic crust, which shallows near the projected centre of the subducting Carnegie Ridge. We also observe a strong shallow positive conversion in the Ecuadorian forearc near the Borbon Basin indicating a major discontinuity at a depth of ∼7 km. This conversion is not ubiquitous and may be the top of the accreted terranes. We also observe significant north–south changes in shear wave velocity. The velocity changes indicate variations in the accreted terranes and may indicate an increased amount of hydration beneath the Manabí Basin. This change in structure also correlates geographically with the southern rupture limit of multiple high magnitude megathrust earthquakes. The earthquake record along the Ecuadorian trench shows that no event with a Mw >7.4 has ruptured south of ∼0.5°S in southern Ecuador or northern Peru. Our observations, along with previous studies, suggest that variations in the forearc crustal structure and subducting oceanic crust may influance the occurrence and spatial distribution of high magnitude seismicity in the region.

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Manchuel, Kevin, Marc Régnier, Nicole Béthoux, Yvonne Font, Valentí Sallarès, Jordi Díaz, and Hugo Yepes. "New insights on the interseismic active deformation along the North Ecuadorian-South Colombian (NESC) margin." Tectonics 30, no. 4 (July 21, 2011): n/a. http://dx.doi.org/10.1029/2010tc002757.

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ARIAS, RUTH, NELSON ESPINOSA-ORTEGA, ITALO REVILLA, RAFFAELLA ANSALONI, and SALVATORE TOMASELLO. "Gynoxys revolutifolia (Senecioneae, Asteraceae): A new species from southern Ecuador." Phytotaxa 644, no. 3 (April 16, 2024): 211–19. http://dx.doi.org/10.11646/phytotaxa.644.3.4.

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Gynoxys is a very diverse genus of Asteraceae with an Andean distribution from Venezuela to northern Argentina. It comprises about 130 species, 34 of which are recorded in Ecuador. In the present study, we describe Gynoxys revolutifolia, a new species occurring in Ecuador between Loja and Zamora-Chinchipe provinces. The new species is a shrub or treelet characterized by coriaceous leaves with a strongly revolute margin. After an accurate revision of the main Ecuadorian herbaria and field surveys, we provide a comprehensive comparison of G. revolutifolia with the species it was previously misidentified as. We also provide information concerning the chemical composition, distribution range and conservation status of the new species.

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Marcaillou, Boris, Jean-Yves Collot, Alessandra Ribodetti, Elia d'Acremont, Ammy-Adoum Mahamat, and Alexandra Alvarado. "Seamount subduction at the North-Ecuadorian convergent margin: Effects on structures, inter-seismic coupling and seismogenesis." Earth and Planetary Science Letters 433 (January 2016): 146–58. http://dx.doi.org/10.1016/j.epsl.2015.10.043.

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León-Ríos, Sergio, Hans Agurto-Detzel, Andreas Rietbrock, Alexandra Alvarado, Susan Beck, Phillipe Charvis, Benjamin Edwards, et al. "1D-velocity structure and seismotectonics of the Ecuadorian margin inferred from the 2016 Mw7.8 Pedernales aftershock sequence." Tectonophysics 767 (September 2019): 228165. http://dx.doi.org/10.1016/j.tecto.2019.228165.

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Mendoza Mejia, Jorge Luis, Mairelys Jaciel Torrealba Peña, Isidro Ignacio Alcívar Vera, and Felix Reinaldo Pastrán. "The learning styles and their impact on the academic education of ecuadorian university students." Revista Colombiana de Ciencias Sociales 14, no. 2 (August 15, 2023): 607–29. http://dx.doi.org/10.21501/22161201.4043.

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The objective of this research was to learn about the influence of the use of learning styles in the virtual academic formation of ULEAM students, Extension El Carmen. To this end, the positivist paradigm was used through the quantitative approach, with correlational level field research. The study population was one thousand five hundred and two (1502) students, calculating a sample of three hundred and seven (307), which was extracted with 95% confidence criteria and 5% margin of error, taking two sections of each course at different levels, with the purpose of knowing different opinions from various groups. For the collection of data, the survey technique was used by means of a Likert-type questionnaire, and in this way process the data by using the SPSS version 25. The results obtained show that there is a strong positive correlation in the use of learning styles and the academic training of students. Likewise, it was determined that in the Basic Education career there is a good management of these learning styles, while those of other careers varied from medium to low.

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Mamberti, Marc, Henriette Lapierre, Delphine Bosch, Etienne Jaillard, Jean Hernandez, and Mireille Polvé. "The Early Cretaceous San Juan Plutonic Suite, Ecuador: a magma chamber in an oceanic plateau?" Canadian Journal of Earth Sciences 41, no. 10 (October 1, 2004): 1237–58. http://dx.doi.org/10.1139/e04-060.

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Sections through an oceanic plateau are preserved in tectonic slices in the Western Cordillera of Ecuador (South America). The San Juan section is a sequence of maficultramafic cumulates. To establish that these plutonic rocks formed in an oceanic plateau setting, we have developed criteria that discriminate intrusions of oceanic plateaus from those of other tectonic settings. The mineralogy and crystallization sequence of the cumulates are similar to those of intra-plate magmas. Clinopyroxene predominates throughout, and orthopyroxene is only a minor component. Rocks of intermediate composition are absent, and hornblende is restricted to the uppermost massive gabbros within the sequence. The ultramafic cumulates are very depleted in light rare-earth elements (LREE), whereas the gabbros have flat or slightly enriched LREE patterns. The composition of the basaltic liquid in equilibrium with the peridotite, calculated using olivine compositions and REE contents of clinopyroxene, contains between 16% and 8% MgO and has a flat REE pattern. This melt is geochemically similar to other accreted oceanic plateau basalts, isotropic gabbros, and differentiated sills in western Ecuador. The Ecuadorian intrusive and extrusive rocks have a narrow range of εNdi (+8 to +5) and have a rather large range of Pb isotopic ratios. Pb isotope systematics of the San Juan plutonic rocks and mineral separates lie along a mixing line between the depleted mantle (DMM) and the enriched-plume end members. This suggests that the Ecuadorian plutonic rocks generated from the mixing of two mantle sources, a depleted mid-oceanic ridge basalt (MORB) source and an enriched one. The latter is characterized by high (207Pb/204Pb)i ratios and could reflect a contamination by recycled either lower continental crust or oceanic pelagic sediments and (or) altered oceanic crust (enriched mantle type I, EMI). These data suggest that the San Juan sequence represents the plutonic components of an Early Cretaceous oceanic plateau, which accreted in the Late Cretaceous to the Ecuadorian margin.

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Álvarez Palomeque, Catalina, and Luis Montaluisa Chasiquiza. "Educación, currículo y modos de vida: referentes para la construcción del conocimiento en el contexto ecuatoriano / Education, curriculum and way of life: references for the construction of knowledge in the ecuadorian context." Sophía 1, no. 13 (December 30, 2012): 270. http://dx.doi.org/10.17163/soph.n13.2012.11.

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La educación, además de conocimiento, es formación para la vida. Se debe formar a las personas en las ciencias y en la sabiduría. La ciencia es conocimiento, mientras la sabiduría es un modo de vida acorde con la austeridad y fecundidad de la naturaleza, para dar sentido a nuestra existencia. En este documento se pretende: 1) discutir sobre la educación que puede seguir el Ecuador como comunidad, en el contexto con los demás pueblos de la Tierra y los diversos componentes del cosmos, 2) enmarcar el proceso educativo en un plan de Estado con un modelo sustentable 3) fundamentar la educación en el contexto de un Estado plurinacional y una visión cósmica 4) usar la semiótica para ir de lo concreto hacia la abstracción, 5) repensar los lineamientos para la explicación-comprensión de las ciencias, la creación y aplicación de los conocimientos.

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Michaud, Francois, Jean-Noël Proust, Alexandre Dano, Jean-Yves Collot, Grâce Daniella Guiyeligou, María José Hernández Salazar, Gueorgui Ratzov, et al. "Flare-Shaped Acoustic Anomalies in the Water Column Along the Ecuadorian Margin: Relationship with Active Tectonics and Gas Hydrates." Pure and Applied Geophysics 173, no. 10-11 (January 27, 2016): 3291–303. http://dx.doi.org/10.1007/s00024-015-1230-7.

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Hoenle, Philipp, John Lattke, David Donoso, Christoph von Beeren, Michael Heethoff, Sebastian Schmelzle, Adriana Argoti, Luis Camacho, Bernhard Ströbel, and Nico Blüthgen. "Odontomachus davidsoni sp. nov. (Hymenoptera, Formicidae), a new conspicuous trap-jaw ant from Ecuador." ZooKeys 948 (July 13, 2020): 75–105. http://dx.doi.org/10.3897/zookeys.948.48701.

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One of the largest species in its genus, Odontomachus davidsoni Hoenle, Lattke & Donoso, sp. nov. is described from workers and queens collected at lowland forests in the Chocó-Darién bioregion in coastal Ecuador. The workers are characterized by their uniform red coloration, their large size (16–18 mm body length), and their frontal head striation that reaches the occipital margin. DNA barcodes (COI) and high resolution 2D images of the type material are provided, as well as an updated key for the Neotropical species of Odontomachus. In addition, a three-dimensional digital model of the worker holotype and a paratype queen scanned with DISC3D based on photogrammetry is presented, for the first time in a species description. Findings of large and conspicuous new species are uncommon around the world and suggest that these Ecuadorian rainforests may conceal many more natural treasures that deserve conservation.

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Chiaradia, Massimo, Lluís Fontboté, and Agustín Paladines. "Metal Sources in Mineral Deposits and Crustal Rocks of Ecuador (1° N–4° S): A Lead Isotope Synthesis." Economic Geology 99, no. 6 (September 1, 2004): 1085–106. http://dx.doi.org/10.2113/econgeo.99.6.1085.

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Abstract Ecuador consists of terranes having both continental (Chaucha, Tahuin, Loja terranes) and oceanic (Macuchi, Alao, Salado terranes) affinity, which were accreted to the Amazon craton from Late Jurassic to Eocene. Four main magmatic arcs were formed by the subduction of the Farallon/Nazca plate since the Jurassic: a Jurassic continental arc on the western margin of the Amazon craton, a Jurassic island arc (Alao terrane), an early Tertiary island arc (Macuchi terrane), and a middle-late Tertiary continental arc encompassing the terranes of Macuchi, Chaucha, Tahuin, Loja, and Alao after complete assembly of the Ecuadorian crust. Mineral deposits formed during these magmatic arc activities include porphyry-Cu and gold skarn deposits in association with the Jurassic continental arc, polymetallic volcanic-hosted massive sulfide deposits (VHMS) in association with the Jurassic island arc of Alao, Au-Cu-Zn VHMS deposits in association with the early Tertiary island arc of Macuchi, and porphyry-Cu and precious-metal epithermal deposits in association with the middle-late Tertiary continental-arc magmatism on the newly assembled crust of Ecuador (Macuchi, Chaucha, Tahuin, Loja, and Alao terranes). In this study, we have compiled 148 new and 125 previously published lead isotope analyses on Paleozoic to Miocene metamorphic, intrusive, volcanic, and volcanosedimentary rocks, as well as on Jurassic to Miocene magmatic-related ore deposits of Ecuador. Lead isotope compositions of the magmatic rocks of the four main arc events derive from mixing of various sources including mantle, variably enriched by pelagic sediments and/or by a high 238U/204Pb component, and heterogeneous continental crust rocks. Lead isotope compositions of the Ecuadorian ore deposits display a broad range of values (206Pb/204Pb = 18.3–19.3, 207Pb/204Pb = 15.54–15.74, 208Pb/204Pb = 38.2–39.2), which is as large as the range previously reported for all magmatic-related ore deposits of the Central Andean provinces I and II combined. Ore deposits formed before complete assembly of the Ecuadorian crust through complete accretion of the several terranes (i.e., pre-Eocene) have lead isotope compositions overlapping those of the associated magmatic rocks, suggesting a largely magmatic origin for their lead. In contrast, post-assembly ore deposits (i.e., post-Eocene) have lead isotope compositions that only partly overlap those of the coeval magmatic rocks of the continental arc. In fact, several ore deposits have lead isotope compositions shifted toward those of the basement rocks that host them, suggesting that lead derives from a mixture of magmatic lead and basement-rock lead leached by hydrothermal fluids. Most Ecuadorian ores have high 207Pb/204Pb values (>15.55), suggesting a dominant continental crust or pelagic sediment origin of the lead. However, we caution against concluding that chalcophile metals (for example, Cu and Au) also have a continental crust origin. Ore deposits of the different terranes of Ecuador, irrespective of their age, plot in distinct isotopic fields, which are internally homogeneous. This suggests that lithologic factors had an important control on the lead isotope compositions. Ultimately, lead isotope compositions of the ore deposits of Ecuador mirror the isotopic compositions of the rocks of the host terranes and are consistent with the multiterrane nature of the Ecuadorian crust.

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Bourdon, Erwan, Jean-Philippe Eissen, Marc-André Gutscher, Michel Monzier, Pablo Samaniego, Claude Robin, Claire Bollinger, and Joseph Cotten. "Slab melting and slab melt metasomatism in the Northern Andean Volcanic Zone : adakites and high-Mg andesites from Pichincha volcano (Ecuador)." Bulletin de la Société Géologique de France 173, no. 3 (May 1, 2002): 195–206. http://dx.doi.org/10.2113/173.3.195.

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Abstract Situated in the fore-arc of the Northern Volcanic Zone (NVZ) of the Andes in Ecuador, Pichincha volcano is an active edifice where have been erupted unusual magmas as adakites and high-Mg andesites. The particular geodynamic setting of the ecuadorian margin (i.e. the flat subduction of the Carnegie Ridge) suggests that thermo-barometric conditions for the partial melting of the oceanic crust are accomplished beneath this volcano. Pichincha adakites possess all the geochemical and isotopic characteristics of slab melts described in various other arc settings. High-Mg andesites with geochemical characteristics close to those of adakites present strong enrichments in MgO that suggest that, once they were produced by ca. 10 % partial melting of the downgoing subducted slab, some adakites en route to the surface strongly interacted with the peridotitic mantle wedge. Adakitic magmas could then represent, as in many other arcs where slab melting occurs, the principal metasomatic agent of the mantle in the NVZ in Ecuador.

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Gassner, L., N. Thiel, and A. Rietbrock. "A synthetic 2-D-elastic full-waveform inversion study for the Ecuadorian margin—resolution capability of a dense onshore/offshore network." Geophysical Journal International 222, no. 2 (May 16, 2020): 1236–44. http://dx.doi.org/10.1093/gji/ggaa244.

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SUMMARY Subduction zones are the places on the Earth where the greatest earthquakes occur. It is now widely accepted that seismic asperities at the interface of subducting plates play a major role in whether a region of a subduction zone behaves seismically, creating strong earthquakes or exhibits aseismic slip. In the last decades, huge advances have been made to decipher the underlying processes; however, the physical parameters along the subduction zone interfaces are still not very well known due to a sparsity of high-resolution experiments and significant costs associated with amphibious seismic experiments. Therefore, synthetic tests are needed to investigate the potential of currently possible high density seismic deployments and to aid future experiment design. As standard local earthquake traveltime tomography in a subduction zone setting cannot resolve structures on a kilometre scale at depth, we explore the suitability of full-waveform inversion (FWI) to increase resolution by using amplitude and phase information in the recorded earthquake seismograms. We apply 2-D-elastic FWI to synthetic earthquake data, using vertical and horizontal receivers, and utilize a realistic model of the seismic velocities at the Ecuadorian margin. We add perturbations within the subducting plates of 4×4 km and 2×2 km in P- and S-wave velocities, respectively, such that potential crosstalk between the two models can be identified. Our results show that the location and amplitude of the perturbations can be reconstructed in high quality down to approximately 70 km depth. We find that the inversion of the S-wave velocity prior to the inversion of the P-wave velocity is necessary to guarantee a good reconstruction of both models; however, the spatial resolution of the S-wave model is superior to the P-wave model. We also show that frequencies up to 1 Hz are sufficient to achieve high resolution. Further tests demonstrate how results depend on the accuracy of the estimated source orientation. Resulting models do not suffer in quality as artefacts near the source positions compensate for the inaccuracy of source orientation. If sources are located within the subducted plate instead of beneath, resulting models are comparable and the convergence of the inversion scheme is sped up. The accuracy of the source position within the model compared to the true earthquake location is critical and implies that earthquake relocation during the inversion process is necessary, in a similar way as in local earthquake traveltime tomography.

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Tamay, J., J. Galindo-Zaldívar, Y. M. Martos, and J. Soto. "Gravity and magnetic anomalies of ecuadorian margin: Implications in the deep structure of the subduction of Nazca Plate and Andes Cordillera." Journal of South American Earth Sciences 85 (August 2018): 68–80. http://dx.doi.org/10.1016/j.jsames.2018.04.020.

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Michaud, Francois, Jean-Noël Proust, Alexandre Dano, Jean-Yves Collot, Grâce Daniella Guiyeligou, María José Hernández Salazar, Gueorgui Ratzov, et al. "Erratum to: Flare-Shaped Acoustic Anomalies in the Water Column Along the Ecuadorian Margin: Relationship with Active Tectonics and Gas Hydrates." Pure and Applied Geophysics 173, no. 4 (March 15, 2016): 1429. http://dx.doi.org/10.1007/s00024-016-1262-7.

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Cadena, Edwin, Juan Abella, and Maria Gregori. "The first Oligocene sea turtle (Pan-Cheloniidae) record of South America." PeerJ 6 (March 23, 2018): e4554. http://dx.doi.org/10.7717/peerj.4554.

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The evolution and occurrence of fossil sea turtles at the Pacific margin of South America is poorly known and restricted to Neogene (Miocene/Pliocene) findings from the Pisco Formation, Peru. Here we report and describe the first record of Oligocene (late Oligocene, ∼24 Ma) Pan-Cheloniidae sea turtle remains of South America. The fossil material corresponds to a single, isolated and well-preserved costal bone found at the Montañita/Olón locality, Santa Elena Province, Ecuador. Comparisons with other Oligocene and extant representatives allow us to confirm that belongs to a sea turtle characterized by: lack of lateral ossification, allowing the dorsal exposure of the distal end of ribs; dorsal surface of bone sculptured, changing from dense vermiculation at the vertebral scute region to anastomosing pattern of grooves at the most lateral portion of the costal. This fossil finding shows the high potential that the Ecuadorian Oligocene outcrops have in order to explore the evolution and paleobiogeography distribution of sea turtles by the time that the Pacific and the Atlantic oceans were connected via the Panama basin.

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Vallejo, Cristian, Santiago Almagor, Christian Romero, Jose L. Herrera, Vanessa Escobar, Richard A. Spikings, Wilfried Winkler, and Pieter Vermeesch. "Sedimentology, Provenance and Radiometric Dating of the Silante Formation: Implications for the Cenozoic Evolution of the Western Andes of Ecuador." Minerals 10, no. 10 (October 21, 2020): 929. http://dx.doi.org/10.3390/min10100929.

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The Silante Formation is a thick series of continental deposits, exposed along a trench-parallel distance of approximately 300 km within the Western Cordillera of Ecuador. The origin, tectonic setting, age and stratigraphic relationships are poorly known, although these are key to understand the Cenozoic evolution of the Ecuadorian Andes. We present new sedimentological, stratigraphic, petrographic, radiometric and provenance data from the Silante Formation and underlying rocks. The detailed stratigraphic analysis shows that the Silante Formation unconformably overlies Paleocene submarine fan deposits of the Pilalo Formation, which was coeval with submarine tholeiitic volcanism. The lithofacies of the Silante Formation suggest that the sediments were deposited in a debris flow dominated alluvial fan. Provenance analysis including heavy mineral assemblages and detrital zircon U-Pb ages indicate that sediments of the Silante Formation were derived from the erosion of a continental, calc-alkaline volcanic arc, pointing to the Oligocene to Miocene San Juan de Lachas volcanic arc. Thermochronological data and regional correlations suggest that deposition of the Silante Formation was coeval with regional rock and surface uplift of the Andean margin that deposited alluvial fans in intermontane and back-arc domains.

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Matusov, Eugene. "A student's right to freedom of education and a teacher's fiduciary obligation to support it." Dialogic Pedagogy: An International Online Journal 8 (September 24, 2020): SF97—SF114. http://dx.doi.org/10.5195/dpj.2020.357.

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I feel honored to receive so many deep, critical, supportive, expanding, and thought-provoking commentaries on my original paper “A student’s right to freedom of education” from undergraduate university students, educators, and educational researchers. These commentaries involve different genres: on-the-margin contextual comments, theoretical essays, ethnographies of their pedagogical practices, reflective sharing of good and bad personal educational experiences, personal authorial opinions, critiques, students’ course evaluations, analysis of science-fiction literature, investigation of Bakhtin’s biography, video replies, a list of questions, and so on. Once Socrates complained about the print text that it is impossible to ask the text new questions – the text won’t reply to these questions. In this special essay, we tried to overcome this problem by involving each other in address-reply commentaries on each other’s texts. We want to invite the readers of this special issue to join us in our dialogues of agreement and disagreement. In my reply to the commentaries, I want to focus on the issues raised by the commentators that most touched me. This focus is on the relationship between a student’s authorial education and a teacher’s authorial teaching, where “teacher” is understood on a range between an individual educator and the entire society. I want to apologize in advance if I left out important concerns that some of the commentators wanted me to address (feel free to raise it again on the margin) if I severely misinterpreted their idea or point (please correct me on the margin). Here I focused on the following six major issues raised by the commentators. The first issue is raised by several undergraduate students from Canada, Russia, and South Korea about the possibility (and reality) of some students actively rejecting their freedom of education. Isn’t it a case for rejection of my call for a student’s right to freedom of education? The second issue raised by many commentators is about imaginary and real cases when foisted education is effective and even, arguably, more effective than student-owned education. Do these cases defeat my overall argument that student’s freedom of education is required by education itself? The third issue was introduced by my colleague and a proponent of self-directed learning Kevin Currie-Knight when he asked a deceptively simple question of what I mean by “student.” Usually, the role of a student is defined either by the institution or by the teacher, which implicitly goes against the spirit of my claim for a student’s right to freedom of education. The fourth issue eloquently raised by an Ecuadorian undergraduate exchange student, Juan Francisco Poveda, studying at the Kyung Hee University in Seoul, about whether education must be subordinated to the needs of the society. Fifth, I consider the relationship between the education-for-myself and the education-for-the-other, the new terms introduced by my Russian colleagues. My overall vista in considering this relationship is authorship: the student’s educational authorship or the teacher’s pedagogical authorship. In a disagreement with some commentators and in an agreement with some other commentators, I argue that the teacher’s pedagogical authorship must be subordinated to the student’s educational authorship through the teacher’s pedagogical fiduciary obligation. Finally, I will revisit the Kantian educational paternalism by considering the two, arguably, most powerful and extreme cases for foisted education: foisted education for the survival of the society and foisted education for a student’s agency awakening. In my conclusion, I will summarize the presented reasons for why a student’s freedom is needed for education and briefly discuss how to test my claims.

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Clark, A. Kim. "Globalization Seen from the Margins: Indigenous Ecuadorians and the Politics of Place." Anthropologica 39, no. 1/2 (1997): 17. http://dx.doi.org/10.2307/25605848.

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Carrillo, Paul, Dina Pomeranz, and Monica Singhal. "Dodging the Taxman: Firm Misreporting and Limits to Tax Enforcement." American Economic Journal: Applied Economics 9, no. 2 (April 1, 2017): 144–64. http://dx.doi.org/10.1257/app.20140495.

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Reducing tax evasion is a priority for many governments. A growing literature argues that verifying taxpayer reports against third-party information is critical for tax collection. However, effectiveness can be limited when tax authorities face constraints to credible enforcement and taxpayers make offsetting adjustments on other margins. We exploit a policy intervention in which Ecuadorian firms were notified about detected revenue discrepancies. Most firms simply failed to respond. Firms that responded increased reported revenue, matching the discrepancy amount when provided. However, they also increased reported costs by 96 cents per dollar of revenue adjustment, resulting in minor increases in tax collection. (JEL D22, H25, H26, O23)

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Camacho, M. Alejandra, Diego G. Tirira, Carl W. Dick, and Santiago F. Burneo. "Lophostoma carrikeri (Allen, 1910) (Chiroptera: Phyllostomidae): first confirmed records in Ecuador." Check List 10, no. 1 (February 1, 2014): 217. http://dx.doi.org/10.15560/10.1.217.

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Herein we confirm the occurrence of Lophostoma carrikeri in Ecuador. One adult female was collected in Orellana province on 17 September 2012 at Boanamo, Waorani Ethnic Reserve, and another on 5 May 2013 at Yasuni Research Station, Yasuni National Park. These records extend the distributional range of the species about 570 km northwest of the nearest previously known record in Jenaro Herrera, Loreto, Peru. Both Ecuadorian localities are characterized by well-conserved primary Terra Firme rainforest. Morphological characters of the specimens presented here broaden the known intraspecific variation in this taxon, including uniformly dark ears without white margins, undeveloped sagittal crests, and smaller forearm size than previously reported. In addition, information on ectoparasites for this species in Ecuador is provided.

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Thoerle, Lisa, and ALEXANDER C. HIRTZ. "Three new Lepanthes species (Pleurothallidinae, Orchidaceae) from Ecuador." Phytotaxa 201, no. 1 (February 25, 2015): 50. http://dx.doi.org/10.11646/phytotaxa.201.1.3.

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The Ecuadorian Lepanthes calochroma, L. peltata, and L. spiculifera are proposed as new species, and are described, illustrated, and compared with the most similar species. A brief history and description of the genus are included. The flowers of L. calochroma are similar to those of L. golbasto, but the plant is larger and the flowers are brilliantly colored with petals with an upper lobe longer than the lower. The flowers of L. peltata have an unusual bladeless lip, resembling that of L. alticola, but the latter is distinguished by much larger flowers with long-acuminate sepals. Lepanthes spiculifera is distinguished from the similar L. zettleri by the unusual blunt-spiculate pedicel bearing smaller flowers with blunt-spiculate sepals, densely pubescent petals, and a lip with long-ciliate margins.

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Middleton, David J. "Ecology, reproductive biology and hybridization in Gaultheria L." Edinburgh Journal of Botany 48, no. 1 (January 1991): 81–89. http://dx.doi.org/10.1017/s0960428600003656.

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The ecology, reproductive biology and hybridization of species in the genus Gaultheria (Ericaceae) has been investigated with particular reference to those species in Ecuador. Most species were found to be plants of disturbed ground particularly on roadside banks and forest margins. The species in Ecuador were not seen to be visited by potential pollinators although fruit set was high. No animals were seen to eat the fleshy fruits. Male sterile plants of many species from throughout the distribution of the genus were observed indicating a higher level of gynodioecism in the genus than previously thought. Empty anthers in two Ecuadorean species suggests that gynodioecism may be present in many species without any clear morphological change. A hybrid between Gaultheria myrsinoides and G. reticulata has been found in Ecuador.

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Gomez-Rodriguez, Victor, Roberto Tolozano-Benites, and Elena Tolozano-Benites. "LA UNIVERSIDAD BOLIVARIANA DEL ECUADOR EL SISTEMA DE EDUCACION SUPERIOR ECUATORIANO Y LA REALIDAD DE UN CANTON Y DE LAS ZONAS DE PLANIFICACION QUE LA ACOGEN." Identidad Bolivariana 5, no. 2 (July 1, 2021): 1–5. http://dx.doi.org/10.37611/ib5ol21-5.

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El conocimiento y la información tienen el poder de transformar las economías y las sociedades. Las universidades, como instituciones de bien público se han convertido en el primer actor social para la generación de conocimientos organizados y en una plataforma para el desarrollo social. Está claro que en los países donde más inversión en educación hay, existe una mayor calidad de vida y hay un mayor ingreso per capital. En los países de América Latina la proporción de personas con educación terciaria es muy baja y, por ello, se ubican en la periferia de la sociedad del conocimiento, lo cual contrasta con el hecho de que, según el Banco Mundial, apenas el 20% de la población controla el 80% de la producción mundial. La mayor parte de los informes de importantes agencias, fundaciones y organizaciones internacionales coinciden en que en América Latina no se cuenta con el capital humano que se necesita para responder y competir contra las regiones que controlan la economía del conocimiento. Esto no se revertirá, en tanto, cada país no tenga la capacidad de incorporar el conocimiento a todos los sectores productivos y de servicio, sus instituciones de educación superior se mantengan al margen de las tendencias internacionales y no se integren a redes de universidades de clase mundial y no se logre el incremento de la tasa de graduados con estudios tecnológicos, de licenciatura, de especialización y doctorado. Ecuador, se ha caracterizado siempre por su riqueza cultural y ambiental. A partir del segundo lustro de este siglo, el país experimentó un crecimiento y una reducción de la pobreza importantes debido al boom del precio del petróleo. Ello permitió avanzar en materia de infraestructura para el desarrollo, en leyes y normativas destinadas a consolidar y desarrollar sectores prioritarios como la educación y la salud.

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de Córdova, Javier Fernández, Carlos Nivelo-Villavicencio, Carolina Reyes-Puig, Ulyses F. J. Pardiñas, and Jorge Brito. "A new species of crab-eating rat of the genus Ichthyomys, from Ecuador (Rodentia, Cricetidae, Sigmodontinae)." Mammalia 84, no. 4 (March 26, 2020): 377–91. http://dx.doi.org/10.1515/mammalia-2019-0022.

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AbstractBased on two adult specimens collected in the Río León (Azuay, Ecuador), we describe a new highland species of a small crab-eating rat of the genus Ichthyomys Thomas (Rodentia, Cricetidae, Ichthyomyini). It is distinguishable from Ichthyomys hydrobates (Winge, 1891), the species phenetically closest to it, by its smaller size, bicolored tail (unicolored in I. hydrobates), broad and heavily fringed hindfoot (narrower and moderately fringed in I. hydrobates), and several craniodental traits (e.g. rostrum short broad; nasals anteriorly truncated; interorbital region narrow; supraorbital margins smoothly rounded; supraorbital foramina small, zygomatic plate very narrow; incisors opisthodont; length of M3 half that of M2). The new species occurs in the western Andes in southern Ecuador and is allopatric with Ichthyomys stolzmanni Thomas, 1893, which also has a bicolored tail but is larger. The new species brings the number of Ecuadorean Ichthyomys to four, Ecuador thus becoming the country with the greatest diversity of Ichthyomyini (four genera and eight species).

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MARIANA MARIANA PUENTE et al. "PROFITABILITY IN ECUADORIAN PRIVATE BANKING AND FINANCIAL INCLUSION." Russian Law Journal 11, no. 8s (April 7, 2023). http://dx.doi.org/10.52783/rlj.v11i8s.1302.

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In recent years, financial inclusion has taken importance worldwide, in this sense this research aimed to analyze the relationship between the profitability of Ecuadorian private banking and financial inclusion. The type of research used was quantitative due to it involves data from 15 banking entities between 2002 - 2019, in addition, some linear regression models were applied the same that allowed establishing the relationship among the variables, which showed a positive relationship between bank profitability and inclusion. Financial. The results obtained show that financial inclusion positively affects the profitability of banks in Ecuador. it is concluded that an increase in financial inclusion can generate an improvement in bank profitability, showing a direct and positive relationship between Loans / GDP, Financial Intermediation, Return on assets, Return on equity , Financial Net Margin, it is worth mentioning that financial inclusion allows improving the profitability of banks

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León‐Ríos, Sergio, Lidong Bie, Hans Agurto‐Detzel, Andreas Rietbrock, Audrey Galve, Alexandra Alvarado, Susan Beck, et al. "3D Local Earthquake Tomography of the Ecuadorian Margin in the Source Area of the 2016 Mw 7.8 Pedernales Earthquake." Journal of Geophysical Research: Solid Earth 126, no. 3 (March 2021). http://dx.doi.org/10.1029/2020jb020701.

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"INFORMATION AND COMMUNICATION TECHNOLOGIES IN THE NATIONAL UNIVERSITY OF EDUCATION OF ECUADOR." CHAKIÑAN, REVISTA DE CIENCIAS SOCIALES Y HUMANIDADES, no. 11 (August 1, 2020): 17–30. http://dx.doi.org/10.37135/chk.002.11.01.

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This study is a partial advance of ongoing research whose main objective is the creation, contribution, and analysis of cultural indicators in the Ecuadorian university context. This work focuses specifically on providing a series of indicators on the equipment, use, and consumption of the TIC of students of the National University of Education of Ecuador (UNAE). The methodology used is the quantitative of descriptive-analytical order, based on the data collected in a survey applied on a population sample, made up of 438 students of the total universe between the different careers and cycles offered by the UNAE. The sample has a margin of 95% reliability and an error of 5%. The obtained results showed a high level of equipment, use, and consumption of the different technological devices. Also, this university population spends daily hours in academic and free time activities in cellphones, television, videos, and internet.

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Wickham-Piotrowski, Alexander, Yvonne Font, Marc Regnier, Bertrand Delouis, Olivier Lengliné, Monica Segovia, and Quentin Bletery. "Achieving a Comprehensive Microseismicity Catalog through a Deep-Learning-Based Workflow: Applications in the Central Ecuadorian Subduction Zone." Bulletin of the Seismological Society of America, December 21, 2023. http://dx.doi.org/10.1785/0120230128.

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ABSTRACT Although seismological networks have densified along the Ecuadorian active margin since 2010, visual phase reading, ensuring high arrival times quality, is more and more time-consuming and becomes impossible to handle for the very large amount of recorded seismic traces, even when preprocessed with a detector. In this article, we calibrate a deep-learning-based automatized workflow to acquire accurate phase arrival times and build a reliable microseismicity catalog in the central Ecuadorian forearc. We reprocessed the dataset acquired through the OSISEC local onshore–offshore seismic network that was already used by Segovia et al. (2018) to produce a reference seismic database. We assess the precision of phase pickers EQTransformer and PhaseNet with respect to manual arrivals and evaluate the accuracy of hypocentral solutions located with NonLinLoc. Both the phase pickers read arrival times with a mean error for P waves lower than 0.05 s. They produce 2.7 additional S-labeled picks per event compared to the bulletins of references. Both detect a significant number of waves not related to seismicity. We select the PhaseNet workflow because of its ability to retrieve a higher number of reference picks with greater accuracy. The derived hypocentral solutions are also closer to the manual locations. We develop a procedure to automatically determine thresholds for location attributes to cull a reliable microseismicity catalog. We show that poorly controlled detection combined with effective cleaning of the catalog is a better strategy than highly controlled detection to produce comprehensive microseismicity catalogs. Application of this technique to two seismic networks in Ecuador produces a noise-free image of seismicity and retrieves up to twice as many microearthquakes than reference studies.

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Vera Santos, Rocío. "Saint Martin de Porres “The Black Saint of the Afro‐descendant community in Quito‐Ecuador”: Between segregation, racism, and black resistance." Journal of Latin American and Caribbean Anthropology, November 27, 2023. http://dx.doi.org/10.1111/jlca.12712.

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AbstractIn the neighbourhood Caminos a la Libertad, located in the north‐western part of Quito, every November, a group of Afro‐Ecuadorian women called the Community of Saint Martin & The Martinas pay tribute to Saint Martin de Porres “the Black saint of the Afro‐descendant community.” This celebration is relevant in a context in which the Afro‐Ecuadorian inhabitants of the neighbourhood suffer segregation, racism, and discrimination. What happens in the microcosm of Caminos a la Libertad is, in part, a reflection of the experience of the whole Afro‐descendant population in the capital: A city which has historically created an image of itself as white‐mestizo, and where the presence of Afro‐descendants has been systematically rejected. Based on ethnographic work, participant observation and semi‐structured interviews, in this article I analyse how this community uses the image of Saint Martin de Porres and his celebration to combat racism, promote social cohesion and ethnic and gender empowerment in the neighbourhood, by creating “places of enunciation” and “spiritual citizenship.”

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Martin-Merino, German, Matteo Roverato, and Rafael Almeida. "Volcaniclastic lacustrine sedimentation in the Pleistocene Guayllabamba intermontane basin in the Ecuadorian Andes." Geological Society, London, Special Publications, November 17, 2021, SP520–2021–66. http://dx.doi.org/10.1144/sp520-2021-66.

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AbstractIn this work, we present a description of the sedimentary fill of a well-exposed lacustrine succession in the Ecuadorian Andes. The Guayllabamba basin is an intermontane basin located in the Andean range of Ecuador, and part of its sedimentary history is represented by a volcanically influenced c. 100 m-thick lacustrine unit of Pleistocene age. We create a stratigraphic cross-section from the eastern to western lake margins and identify 19 facies that were used to carry out a palaeoenvironmental reconstruction. The Guayllabamba palaeolake was developed in a tectonic depression surrounded by volcanoes and it was filled with sediments derived from the erosion of the volcanic edifices, the reworking of unconsolidated pyroclastic deposits and deposition of pyroclastic currents into the lake. The lake shows a deepening trend, passing from shallow deltaic sedimentation to varved diatomites with turbidites. Abundant ash-fall beds, monolithological pumiceous deltaic sequences and pumice-dominated thick ignimbrites show the impacts of volcanism on lacustrine sedimentation within this basin. Soft-sediment deformation and gravity flow deposits are common owing to the intrabasinal tectonic activity and to the intrusion of a lava body. Aulacoseira-rich diatomites dominate the background lake sedimentation. The outcrops of the Guayllabamba basin are outstanding examples of the interaction between volcaniclastic and lacustrine sedimentation.

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Journal articles on the topic 'Ecuadorian margin'

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