Petrogenesis of the late Miocene Combia volcanic complex, northwestern Colombian Andes: Tectonic implication of short term and compositionally heterogeneous arc magmatism

Lithos ◽  
2019 ◽  
Vol 330-331 ◽  
pp. 194-210 ◽  
Author(s):  
J.S. Jaramillo ◽  
A. Cardona ◽  
G. Monsalve ◽  
V. Valencia ◽  
S. León
Keyword(s):  
Late Miocene ◽  
Volcanic Complex ◽  
Arc Magmatism ◽  
Short Term ◽  
Tectonic Implication ◽  
Colombian Andes

Magnetostratigraphic dating of late Miocene megalake regressions in Central Eurasia 

2021 ◽  
Author(s):  
Wout Krijgsman ◽  
Dan Palcu ◽  
Irina Patina ◽  
Ionuț Șandric ◽  
Sergei Lazarev ◽  
...  
Keyword(s):  
Late Miocene ◽  
Salt Lake ◽  
Global Ocean ◽  
Water Volume ◽  
Forest Steppe ◽  
Short Term ◽  
Central Eurasia ◽  
Normal Polarity ◽  
Partial Desiccation ◽  
Reversed Polarity

<p>The largest megalake in the record formed in Eurasia during the late Miocene, when the epicontinental Paratethys Sea became tectonically-trapped and disconnected from the global ocean. The Paratethys megalake was characterized by several episodes of hydrological instability and partial desiccation, but the chronology, magnitude and impacts of these paleoenvironmental crises are poorly known. The Panagia section on the Taman Peninsula of Russia is the only place known to host a continuous sedimentary record of the late Miocene hydrological crises of Paratethys. Paleomagnetic measurements allow the development of a polarity pattern that can be used to date the regression events. The Panagia polarity pattern consists of 17 polarity intervals, 9 of normal polarity and 8 of reversed polarity, plus 4 additional short-term polarity fluctuations, that are inferred to correspond to the 11-7.5 Ma interval. We identified four major regressions that correlate with aridification events, vegetation changes and faunal turnovers in large parts of Europe. Our paleogeographic reconstructions reveal that Paratethys was profoundly transformed during the regression episodes, losing ~1/3 of the water volume and ~70% of its surface during the most extreme events. The remaining water was stored in a central salt-lake and peripheral desalinated basins while vast regions (up to 1.75 million km2) became emerged land, suitable for the development of forest-steppe landscapes. The dry episodes of the megalake match with climate, food-web and landscape changes throughout Eurasia but the exact triggers and mechanisms remain to be resolved.</p>

Senecio piedrahitae (Compositae, Senecioneae), a new species from the Colombian Andes

Phytotaxa ◽  
2016 ◽  
Vol 283 (1) ◽  
pp. 91
Author(s):  
JOEL CALVO ◽  
FABIO ÁVILA
Keyword(s):  
New Species ◽  
Central Andes ◽  
Volcanic Complex ◽  
Colombian Andes ◽  
A New Species

A new species of Senecio gr. Lasiocephalus from the Central Andes of Colombia is described. It is a scandent subshrub recognized by its lanceolate leaves, clearly petiolated the middle cauline ones, asymetrical at the lamina base, floccose above and lanate beneath, by its synflorescence branches densely lanate, and glabrescent or slightly arachnoid involucre. It is known from the páramos of the volcanic complex Tolima-Santa Isabel-Ruiz. The morphologically closest taxon is S. otophorus var. christophori.

Short-term variations of diffuse CO2 and H2S at the summit crater of Teide volcano, Tenerife, Canary Islands

2020 ◽  
Author(s):  
Mar Alonso ◽  
Harry T. A. Hoffman ◽  
Joseph G. Smith ◽  
Erin Thompson ◽  
Fátima Rodríguez ◽  
...  
Keyword(s):  
Monitoring Program ◽  
Summit Crater ◽  
Rift System ◽  
Volcanic Complex ◽  
Short Term ◽  
Volcanic System ◽  
Applied Ecology ◽  
Quiescence Period ◽  
Using Data ◽  
Teide Volcano

<p>Tenerife (2,034 km<sup>2</sup>) is the central and largest island of the Canarian archipelago, located about 100 km west of the African coast between 27º37’ and 29º25’N and between 13º20’ and 18º10’W. The structure of Tenerife is controlled by a volcano-tectonic rift-system with NW, NE and NS directions with Teide volcano located in the intersection of the three rifts. Teide is the highest stratovolcano in the Atlantic Ocean reaching 3,718 m.a.s.l. with its last eruption occurred in 1798 through an adventive cone of Teide-Pico Viejo volcanic complex. Persistent degassing activity, both visible and diffuse, takes place at the summit cone of the volcano, being the diffuse degassing the principle degassing mechanism of Teide (Mori et. al., 2001; Pérez et. al., 2013). As part of the volcanic monitoring program of INVOLCAN in Tenerife, 8 surveys were performed during summer 2019 in order to evaluate the short term variations of diffuse CO<sub>2</sub> and H<sub>2</sub>S emissions in the summit crater. The emissions were calculated using data from 38 sampling sites homogeneously distributed inside the crater covering an area of 6,972 m<sup>2</sup> by means of a portable CO<sub>2</sub> and H<sub>2</sub>S fluxmeter using the accumulation chamber method (Parkinson 1981). During the study period, CO<sub>2</sub> and H<sub>2</sub>S emissions ranged from 33 ± 5 to 93 ± 25 t/d and from 0.6 ± 0.2 to 4 ± 0.1 kg/d, respectively. Despite the small changes observed in the temporal evolution, values are considered normal for a quiescence period in Teide volcanic system. Short term variations in CO<sub>2</sub> and H<sub>2</sub>S emissions indicate changes in the activity of the system and can be useful to understand the behaviour of the volcanic system and as forecast of future volcanic activity.</p><p><strong>References<br></strong>Mori T. et al. (2001). Chemical Geology, 177, 85–99.<br>Parkinson K. J. (1981). Journal of Applied Ecology, 18, 221–228.<br>Pérez N. M. et al. (2013). Journal of the Geological Society, 170, 585–592.</p>

scholarly journals Physicochemical characteristics of blackberry (Rubus glaucus Benth.) fruits from four production zones of Cundinamarca, Colombia

2016 ◽  
Vol 34 (3) ◽  
pp. 336-345 ◽  
Author(s):  
Manuel Fernando Vergara ◽  
Jessica Vargas ◽  
John Fabio Acuña
Keyword(s):  
Irrigation System ◽  
Physicochemical Characteristics ◽  
International Markets ◽  
Climatic Conditions ◽  
Soluble Solids ◽  
Fruit Characteristics ◽  
High Demand ◽  
Short Term ◽  
Colombian Andes

Blackberries play an important role in human nutrition, due to the elevated content of certain bioactive compounds including ascorbate, anthocyanins, phenolic acids, carbohydrates, and proteins. Blackberry Rubus glaucus from Colombian Andes has a high demand on regional and international markets and there is much interest in its cultivation to increase the com mercial offer. In four blackberry producing municipalities of Cundinamarca province, fruits were harvested for different quality tests based on the availability of hydric resources in the zone and their influence on fruit characteristics according to the precipitation of each zone, since the crops did not have an irrigation system. The variables, such as size, fresh weight, tex ture, pH, titratable total acids (TTA), total soluble solids (TSS), and color were evaluated to compare the quality of the fruits between the municipalities, finding that fruits from Silvania had the greater size but, in turn, were the least consistent. El Colegio zone presented the sweetest fruits and together with Pasca had the highest acidity percentage. The color of Pasca and Silvania fruits was the most attractive for commercialization parameters. These parameters, even when management and agro-climatic conditions between municipalities were very similar, allows knowing the positive attributes and determine the factors that need to be improved and to project on a short-term future productions acceptable on the international market.

scholarly journals Shallow-seated controls on the evolution of the Upper Pliocene Kopasz-hegy nested monogenetic volcanic chain in the Western Pannonian Basin (Hungary)

2011 ◽  
Vol 62 (6) ◽  
pp. 535-546 ◽  
Author(s):  
Gábor Kereszturi ◽  
Károly Németh
Keyword(s):  
Late Miocene ◽  
Pannonian Basin ◽  
Basaltic Magma ◽  
Scoria Cone ◽  
Volcanic Field ◽  
Early Pleistocene ◽  
Volcanic Complex ◽  
Lateral Migration ◽  
Volcanic Chain ◽  
Groundwater Supply

Shallow-seated controls on the evolution of the Upper Pliocene Kopasz-hegy nested monogenetic volcanic chain in the Western Pannonian Basin (Hungary)Monogenetic, nested volcanic complexes (e.g. Tihany) are common landforms in the Bakony-Balaton Highland Volcanic Field (BBHVF, Hungary), which was active during the Late Miocene up to the Early Pleistocene. These types of monogenetic volcanoes are usually evolved in a slightly different way than their "simple" counterparts. The Kopasz-hegy Volcanic Complex (KVC) is inferred to be a vent complex, which evolved in a relatively complex way as compared to a classical "sensu stricto" monogenetic volcano. The KVC is located in the central part of the BBHVF and is one of the youngest (2.8-2.5 Ma) volcanic erosion remnants of the field. In this study, we carried out volcanic facies analysis of the eruptive products of the KVC in order to determine the possible role of changing magma fragmentation styles and/or vent migration responsible for the formation of this volcano. The evolution of the KVC started with interaction of water-saturated Late Miocene (Pannonian) mud, sand, sandstone with rising basaltic magma triggering phreatomagmatic explosive maar-diatreme forming eruptions. These explosive eruptions in the northern part of the volcanic complex took place in a N-S aligned paleovalley. As groundwater supply was depleted during volcanic activity the eruption style became dominated by more magmatic explosive-fragmentation leading to the formation of a mostly spatter-dominated scoria cone that is capping the basal maar-diatreme deposits. Subsequent vent migration along a few hundred meters long fissure still within the paleovalley caused the opening of the younger phreatomagmatic southern vent adjacent to the already established northern maar. This paper describes how change in eruption styles together with lateral migration of the volcanism forms an amalgamated vent complex.

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