Ferencz, Margot Melisa. Syn- and post-eruptive controls on cinder cone morphology and distribution in the Nyambeni hills volcanic field, Kenya. Retrieved from https://doi.org/doi:10.7282/T36M38N4
DescriptionSyn- and post-eruptive controls on cinder cone morphology are identified in the Nyambeni Hills volcanic field of Kenya. The morphology of 65 cinder cones in the Nyambeni Hills volcanic field including cone height, crater width, and basal width in addition to the ellipticity and azimuth of elongation of 372 craters were measured using a combination of topographical maps, publically available satellite imagery, and freely downloadable digital elevation models (DEM). Morphological data from the Nyambeni Hills volcanic field are compared with the morphology of cones from two subduction-associated cinder cone fields (the Guatemalan Salvadorian volcanic field of Central America and the Lamongan volcanic field of Indonesia) and one rift-associate field (the Cima volcanic field of California) to better understand the role of tectonic setting and climate on cone morphology. In the Nyambeni Hills volcanic field the tectonic regime is the most influential factor on cone morphology and distribution. Cone morphologies both corroborate and refute outstanding predictions about subduction-associated cones versus intraplate rift-associated cones. Cones within the Nyambeni Hills volcanic field are more elongated than those from the Guatemalan Salvadorian volcanic field and have an average axial ratio of 0.74. Elongated cones from the Nyambeni Hills display a preferential NNE orientation compatible with an east-west regional extension model over the lifetime of the volcanic field. The orientation of the entire field trends more NE than the signal preserved by elongated cones. Morphological trends in the Nyambeni Hills volcanic field support the hypothesis that the youngest cinder cones are located in the center of the field and are progressively older moving east or west. Differences in cone distribution between the north and south ends of the Nyambeni Hills in addition to age-related morphological trends attest to magma supply heterogeneity and the centralization of the magmatic system over time. Cinder cone morphology from the four study sites shows either no correlation or very weak correlations between morphological parameters and climate.