Pablo Núñez Demarco

Universidad de la República de Uruguay | UdelaR · Instituto de Ciencias Geológicas

Mesosaurs have long been considered to be small to mid-sized aquatic to semiaquatic amniotes that lived in Gondwana during the Early Permian or Late Carboniferous, according to recent research that showed their ghost range extending back to the Pennsylvanian. Previous morphometric analyses based on several hundred mesosaur specimens, including mate...

Uruguayan ammonoids are preserved in phosphate and siderite nodules found at the basalmost tillite-like conglomerates of the San Gregorio Formation. This lithostratigraphic unit was deposited under glacial conditions and its age (as well as that of the nodules) has been highly debated because glaciations were intermittent in Gondwana during the Lat...

This work delves into the intricate Paleoproterozoic geological setting of Uruguay, focusing on the Rio de la Plata Craton (RPC) and its prominent constituent Piedra Alta Terrane (PAT). The PAT constitutes the core of the RPC, characterized as a complex geological entity that encompasses a granite-migmatite basement, metamorphic belts, granite intr...

RESUMEN Presentamos el primer catálogo de eventos sísmicos históricos e instrumentales ocurridos en Uruguay y la región de la cuenca de Plata, que es crucial para los estudios de peligrosidad sísmica. Las regiones intracontinentales constituyen áreas que presentan largos períodos de recurrencia entre terremotos; Por lo tanto, es muy importante tene...

Popularization article in the magazine "Canopus - Uruguayan Astronomy Magazine" about meteorite classification. Artículo de divulgación en la revista "Canopus - Revista Uruguaya de Astronomía" sobre clasificación de meteoritos.

La Carta Geológica del Uruguay digital a escala 1.500.000 ha sido objeto de una nueva actualización respecto a la que se encuentra disponible en el Geoportal de DINAMIGE desde el año 2017 y que fue presentada en el Congreso Uruguayo de Geología en el año 2022 . La renovación de este trabajo cartográfico ha comprendido el análisis y reanálisis de da...

Potential field filters are widely used in exploration and interpretation of geologic structures, archaeological sites, hazards assessment, and in engineering and environmental studies. There are countless filters and attributes and their number keeps growing: directional, horizontal and vertical derivatives; analytic, monogenic and direct analytic...

Mesosaurs were small amphibious tetrapods that lived in western Gondwana during the early Permian or even earlier, when temperate Carboniferous–Permian conditions initiated after the glaciations that affected the southern region of Pangea. In this contribution, we applied traditional linear regression morphometrics to analyse proportions of both th...

Mesosaurs are basal amniotes that lived at the beginning of the Permian or close to the Permo-Carboniferous boundary. Despite the several hundred specimens that have been found, including complete skeletons of adult and juvenile individuals, mesosaur taxonomy has been subjected to a high controversy over time. Currently, three monotypic genera, Mes...

During the last years, geophysical surveys have been carried out in order to study the possible tectonic origin of Udaeta Lake and the extension and thickness of glacio-lacustrine deposits cropping out in the Río Valdez mouth. In both cases, geophysical methods proved to be a powerful tool for the investigation of Quaternary tectonic and glacial ac...

The integrated observation of geology, gammaspectrometry and magnetometry of southern Uruguay was made possible by the high-resolution aerogeophysical survey carried out during 2014 and 2015. This survey covers nearly the outcropping area of the Uruguayan basement. Previous studies focused on the Proterozoic and Mesozoic dike swarms present in the...

Spectral methods have been applied for more than 40 years to calculate the depth to magnetic sources and the Curie point depth or Moho depth. Unfortunately, conceptual, theoretical and methodological errors, as well as, subjective approaches and lack of rigor in the application of the method are common. This has affected reproducibility, credibilit...

A rock magnetic, paleomagnetic and absolute intensity study was conducted on 21 basic dike swarms situated in the Zapicán area (Lavalleja, Uruguay). Paleomagnetic directions revealed mostly normal polarity magnetizations with few intermediate and reverse polarity dikes. Combining data from a previous study, a mean paleodirection obtained is Dec = 3...

New high-resolution airborne magnetic data of Uruguay allowed constructing new maps concerning the spatial distribution of dyke swarms, main faults and other magnetic bodies, which compose the Uruguayan Shield. We combined geophysical analyses (vertical derivatives, upward continuation, Euler deconvolution), structural analyses of the magnetic maps...

The Yaguarí and the Buena Vista formations from Uruguay are historically correlated to the Brazilian Rio do Rasto and Sanga do Cabral formations, respectively, as they have some lithostratigraphic similarities, indicating a Permo-Triassic or even Triassic age of the Yaguarí-Buena Vista succession. However, they differ in the fossil indexes that cha...

Se describe en este trabajo una nueva unidad compuesta por cuarcitas, metaconglomerados, esquistos calcáreos, filitas y mármoles, afectadas por metamorfismo medio por deformación dúctil. Litotipo y área tipo de esta unidad se localiza al margen del camino vecinal que unía la Estancia Vidal con el poblado de Polanco, en el paso de la Cañada del Baña...

In the Río Valdez mouth, located in the southeastern coast of Fagnano lake, Tierra del Fuego, an outcrop of 7 m thick lacustrine sediments was identified. Taking into account geomorphological and sedimentological surveys, such outcrop was interpreted as a rhythmic glacio-lacustrine deposit, formed in a frontal morainic complex during the Pleistocen...

La existencia de dos modelos tectonoestratigráficos para el Uruguay ha generado múltiples confusiones estratigráficas en las interpretaciones regionales. Ambos modelos implican interpretaciones estratigráficas diferentes e incluso interpretaciones geológicas diferentes. Más aún, cada unidad incluida en el Cinturón Dom Feliciano en Uruguay no solo p...

Mesosaurs are lizard-like reptiles that lived at the beginning of the Permian Period (280–290 million years ago) or even earlier. Mesosaurs are known from thousands of skeletons recovered in Uruguay, Brazil, and Southern Africa, including young and adult individuals and even an embryo and a pregnant female. For years, mesosaurs have been considered...

The aim of this work is to propose a new stratigraphic scheme of the Barriga Negra Formation, in order to solve the controversies in one of the most discussed units of Uruguay. Here, we introduce a new map (unmodified since 1984) and amend the stratigraphic profile for the Barriga Negra Formation, establishing the correct sequence, order and thickn...

We conducted a magnetotelluric (MT) study from Paleoproterozoic Rio de la Plata Craton, in Uruguay, toward Paleozoic‐Mesozoic Paraná Basin, in Brazil. The 850‐km‐long MT transect comprises 35 evenly spaced broadband electromagnetic soundings sites. In the Paraná Basin, 11 additional long‐period measurements were acquired to extend the maximum depth...

En este trabajo presentamos una revisión histórica de la evolución del conocimiento geológico en Uruguay, y particularmente, de las divisiones estructurales precámbricas del territorio nacional. Mostramos su relación contextualizada para cada etapa de la evolución de las teorías y técnicas experimentales regionales y globales. Las divisiones del pr...

The Polanco-Manguera Azul region, comprised within the schist belt of the Dom Feliciano Belt, has a lithological association mainly composed of calcitic and dolomitic marbles, with intercalations of calc-schists, metaconglomerates, quartzites, BIF and micaschists. Studying in detail the marbles and particularly the calc-schists, it is found that th...

Every year there are now almost two reports of meteorite falls that directly hit human beings or their belongings, which we call “damaging falls”. A new damaging fall occurred on September 18, 2015, when a meteorite impacted a house in the city of San Carlos (Maldonado, Uruguay). A 712 g stone broke through the asbestos cement roof and a wooden sus...

Mesosaurs have been considered strictly aquatic animals. Their adaptations to the aquatic environment are well known and include putative viviparity, along with the presence of several skeletal characters such as a long, laterally compressed tail, long limbs, the foot larger than the manus, and presence of pachyosteosclerotic bones. They were also...

This work is the result of a multiyear effort to use field geology to describe lithologies, to establish contact relationships and to create a sketch of the tectonic evolution of the Meso- to Neoproterozoic metasedimentary successions within the Schist Belt of the Dom Feliciano Belt. This low-grade metamorphic cover rests on the high-grade metamorp...

We developed a new MatLab based program that automatically computes the 2-D spectral analysis of magnetic maps, estimates the Curie point depth, the geothermal gradient and heat flux according to the methods established by Spector and Grant (1970), Bhattacharyya and Leu (1977), Okubo et al. (1985) and Tanaka et al. (1999). The program loads the mag...

Here we present a historical summary of the voyages of three naturalist explorers of the 19th century, as well as the first geological observations of the 20th century, in the region of Barriga Negra, in order to put into perspective the current stratigraphic models that link the low grade metamorphic successions of the Neoproterozoic with discorda...

The hypotheses about the origin of the primitive amniotic tarsus are very speculative. Early studies argued that the origin of the astragalus, one of the largest proximal bones in the tarsus of basal amniotes, was produced by either the fusion of two, three, or even four of the original tarsal bones, the intermedium, the tibiale and the proximal ce...

The hypotheses about the origin of the primitive amniotic tarsus are very speculative. Early studies argued that the origin of the astragalus, one of the largest proximal bones in the tarsus of basal amniotes, was produced by either the fusion of two, three, or even four of the original tarsal bones, the intermedium, the tibiale and the proximal ce...

The hypotheses about the origin of the primitive amniotic tarsus are very speculative. Early studies argued that the origin of the astragalus, one of the largest proximal bones in the tarsus of basal amniotes, was produced by either the fusion of two, three, or even four of the original tarsal bones, the intermedium, the tibiale and the proximal ce...

Mesosaurid biology has been subject of continuous debate since the first description of Mesosaurus tenuidens by Paul Gervais in 1867. Controversy surrounds their environmental and feeding preferences. Most studies suggested that mesosaurids were marine reptiles and perhaps piscivorous predators. Nonetheless, recent work suggests that they inhabited...

In 2011 began the installation of the first geophysical observatory in Uruguay, with the aim of developing the Geosciences. The Astronomical and Geophysical Observatory Aiguá (OAGA) is located within the Cerro Catedral Tourist Farm (-34 ° 20 ’0 .89 ‘S/-54 ° 42 ’44.72′ W, h: 270m). This has the distinction of being located in the center of the South...

We performed a total magnetic field survey in Villasboas locality, located at the north of Piedra Alta tectonostratigraphic terrane, Rio de la Plata Craton, with the aim of determining the nature of a morphologic conspicuous structure in the area. The study showed that shear zones were probably affected by Quaternary events.

The Facultad de Ciencias with support from Comision Sectorial de Investigacion Cientifica (CSIC), PEDECIBA Geociencias, and the Ministerio de Educacion y Cultura (MEC) is installing the first Geophysical (Geomagnetic) Observatory. Uruguay is located in the South Atlantic Magnetic Anomaly, a region that has recorded the lowest values of magnetic fie...

The Tunguska event was an explosion of a bolide that occurred in the Russian Siberia on June 30, 1908. This phenomenon generated diverse hypothesis related to its origin. No crater was formed in the epicenter and obtained particles are scarce and of great uncertainty. Almost one hundred years after, Italian scientists suggest that the Cheko Lake, l...