Descrizione
APPUNTI SULLA MORFOLOGIA DELLA GROTTA MASERA
2213 Lo-Co (Como)
ALFREDO BINI e ALBERTO PELLEGRINI
Summary - Some remarks on the morphology of the cave «Masera» 2213 Lo-Co (Como, Italy) The Masera cave is a temporary overflow spring situated on the eastern side of the western branch of the Como Lake. The cave hydro1ogy has already been studied in a previous work (Cappa 1970). Only the morphology and the structure of the cave are considered in the present paper. It appears from the structural analysis that the cave develops mainly along the bedding-planes with a dip N 5° E and with a !esser frequency a t the junction of groups of joints. The general morphology of the cave is rather uniform because it is a bedding-cave with a quadrangular cross-section. The morphology of details, on the contrary, is very rich with different forms. Among these the most interesting are:
- Bedding piane anastomoses and ceiling channels whose genesis is related to breakdown events. The channels are very frequent and cross the ceiling of passages disappeaning into the rock wall.
- Underground karren due to water during floods.
- Scallops showing the existence of fast flowing water.
- Glacial and alluvial deposits which partially filled the cave for long times.
- Ripple-marks and other beach features due to flood waters.
- Different kinds of dendritic surge marks and erosional rills.
- Thin deposits of manganese on pebbles and formations. Sometimes these films are partially eroded.
From the morpho-structural analysis some information on the speleogenesis and the recent evolution of the cave during the Quaternary is obtained. According to the results reported in this paper the Masera cave (m 329 above sea level) appears to be already existing before the occurrence of the Quaternary glaciations. The glaciations had a minor influence on the cave morphology.