Artisanal and Small Gold Mining and Petroleum Production as Potential Sources of Heavy Metal Contamination in Ecuador: A Call to Action.

Mining and petroleum production are the source of many elements and base materials fundamental for our modern way of life. The flip side of these keystone industries is the environmental degradation they can cause if not properly managed. Metallic mining and petroleum production can contaminate the local ecosystem with sediments, chemicals used in the industrial processes and heavy metals, part of the metallic ore or oil reservoir. The objective of this project was to analyze the spatial distribution of the presence of different potentially hazardous elements that make up the metallic deposits and oil reservoirs in Ecuador, focused mainly on artisanal and small-scale gold mining (ASGM) districts. Additionally, we were interested in analyzing this information under the local political and administrative contexts which are key to determining how likely it is that mismanagement of the local mineral deposits and petroleum exploitation projects will end up causing environmental degradation. An extensive and intensive literature search was conducted for information on the presence and concentration of 19 potentially harmful elements. We analyzed data on 11 metallic deposits throughout Ecuador and a major oilfield in the Ecuadorian Amazon basin. We used geographic information systems to analyze the spatial distribution of these reservoirs and their mineral compositions. The results indicated a widespread distribution and high concentration of elements potentially harmful for human health, such as mercury, cadmium and arsenic, throughout the metallic deposits in Ecuador. This is particularly true for long-exploited ASGM districts, such as Ponce-Enríquez, Portovelo-Zaruma and Nambija. This study highlights the importance of understanding geological diversity and its potential risks to better protect the biological diversity and public health of its inhabitants. Furthermore, we consider our work not as a call to stop ASGM mining nor petroleum production, but on the contrary as a strong call to plan every mining and petroleum production project considering these risks. Moreover, our work is a call to action by the local government and authorities to stop corruption and fulfill their duties overseeing the activities of mining and petroleum companies, stopping illegal mining, helping ASGM communities to improve their environmental standards, finding alternative income sources and protecting the local environment.

Why large porphyry Cu deposits like high Sr/Y magmas?

Porphyry systems supply most copper and significant gold to our economy. Recent studies indicate that they are frequently associated with high Sr/Y magmatic rocks, but the meaning of this association remains elusive. Understanding the association between high Sr/Y magmatic rocks and porphyry-type deposits is essential to develop genetic models that can be used for exploration purposes. Here we present results on a Pleistocene volcano of Ecuador that highlight the behaviour of copper in magmas with variable (but generally high) Sr/Y values. We provide indirect evidence for Cu partitioning into a fluid phase exsolved at depths of ~15 km from high Sr/Y (>70) andesitic magmas before sulphide saturation. This lends support to the hypothesis that large amounts of Cu- and S-bearing fluids can be accumulated into and released from a long-lived high Sr/Y deep andesitic reservoir to a shallower magmatic-hydrothermal system with the potential of generating large porphyry-type deposits.

El deslave del 13 de octubre del 2000 del volcán El Altar

El desastre hidrológico del 13 de octubre de 2000, fue provocado, por el colapso parcial de la cara norte del pico Monja grande del volcán El Altar, este deslave de roca cayo en la Laguna Amarilla y generó una gigantesca ola de agua que viajó valle abajo en forma de un flujo de lodo destructivo. Debido al retroceso de los glaciares, similares avalanchas de roca podrían ocurrir de nuevo en El Altar, pero serían poco frecuentes. (AU)

Diferencias petrográficas y geoquímicas en las lavas del complejo volcánico Pululahua

En el Complejo Volcánico Pululahua (CVP) se observa tres Unidades geológicas caracterizadas por la presencia de lavas dacitas in situ. El estudio de 27 muestras tomadas de estas lavas ha revelado que existen marcadas diferencias petrográficas y geoquímicas entre estas tres Unidades estudiadas del CVP. Se muestran y discuten tales diferencias. Las diferencias petrográficas pueden ser de gran utilidad estratigráfica, mientras que las diferencias geoquímicas muestra que las lavas del Pululahua presentan características adakíticas. (AU)