Local factors in Quaternary glaciers of Cordillera de Merida. Factores locales en la glaciación Cuaternaria de la Cordillera de Mérida.

Silvino Reyes, M. Instituto de Geografía y Conservación de Recursos Naturales, Universidad de Los Andes, Mérida, Venezuela.

An extensive program of integrated land resources surveys carried on high altitude mountain areas, most of them National Parks and Natural Reserves of Cordillera de Mérida, presents indications that help in the interpretation of environmental dynamics and history, from the standpoint of landscape ecology. Natural areas were surveyed at the semidetailed 1:25,000 to 1:50,000 scales by aerophotogrammetric interpretation of aerial photos and the Thematic Mapper Satellite false color image. Detection, mapping and field reconnaissance at the resolution of land systems and land units included geoforms, climate, insolation, vegetation cover and land use. Several geographic correlations showed up in the observation of patterns of appearance and development of glacial geoforms, along and within the environmental factors that are present in the Cordillera de Mérida, as are:

The rainfall and snowfall patterns.
The insolation regimes.
The shape of the Cordillera and its control of topoclimates.
The control and influence of structural geological patterns.
The behavior of the lithological mosaic under glaciation.
The sequence and magnitude of glaciation.
The variation of the thermo-hidrical altitudinal gradients.

Glacial geoforms resulting from the former factors, are expressed as distinct landscapes, affected by the local dominance of some factors over the rest, as can be appreciated in:

The less affected, weakly glaciated Piedras Blancas--Pan de Azúcar land system, local names that reflect the occurrence of clear sandy mantles of periglacial debris that cover exposed slopes in the sun striken periglacial top of Sierra de La Culata, caused by the altiplain topoclimate effect.
The Sierra Nevada land system, massive, round glacial geoforms on igneous outcrops in wet, cloudy mountain climate.
The El Tamá and El Campanario land systems, with their angular and stratigraphically controlled glacial geoforms in the "Aguardiente" sandstone outcrops, with their very extensive moraines and proglacial accumulations, in cloudy mountain climate.

Return to GAGE 1996 meeting