Are volcaniclastics bad enough to make badlands?

Abstract

In the past few decades, terrains of accentuated roughness with variety of topographical features and, due to the diversity of lithology and colors, known as badlands attract great attention not only from the scientist, but from people in general and contribute to the touristic popularization of geosites.

Badlands materials are mainly silty clays and clayey silts. However, they can be formed in volcaniclastics material too and one of the most prominent badlands developed in pyroclastic sediments is Cappadocia, Turkey. Less known are Kazar badlands, Hungary, developed in rhyolitic poorly-consolidated highly porous tuffs and Djavolja varos, Serbia developed in dacito-andesitic poorly-consolidated, poorly-sorted tuffs.

Volcaniclastic rock samples from Kazar badlands, Hungary and Djavolja varos, Serbia were analyzed with the purpose to broaden existing knowledge on materials in which badlands can form. Through analysis of eight unweathered volcaniclastic sediment samples that included petrographic characterization, content of macroelements, pH, electrical conductivity, sodium adsorption ratio and immersion test an attempt was made to answer the question whether volcaniclastics are “bad” enough to make badlands.

After all the analysis conducted, Kazar badlands and Djavolja varos materials have different properties, unique for each site, but are still more similar to each other than to, already known badlands materials. Similar bimodal grain size distribution of Kazar badlands and Djavolja varos reflects sediments erodibility and is making them similar to other badlands generally, while mineralogical composition and weathering processes are the main factors making these two sites a unique badlands group.

Conclusions brought in this study are opening new scientific topic and they imply that volcaniclastic material, even though site-specific, make unique badlands and that, through future research, could bring the possibility of a new badlands classification that will include only volcaniclastics and will bring up small sites like these to the existent geotouristic map.