This characteristic meant that various types of deposits were located there. Espizua (1989) described six drifts in the area (Punta de Vacas, Penitentes, Horcones, Almacenes, Confluencia and undifferentiated moraines). Of these, the moraines of the Punta de Vacas, Confluencia and Penitentes drifts can be identified in the Confluencia zone as glacial deposits because they preserve the morphology imposed by the process. But part of the deposits mapped as Horcones moraine, Almacenes moraine and undifferentiated moraines have a morphology and composition that complicates their interpretation as glacial deposits. The detailed genetic characterization of Aconcagua Expeditions constitutes, consequently, one of the objectives of this contribution.
These deposits, here under review, are distinguished by a landscape of gentle elevations and depressions (hummocks) composed of a greyish, almost monolithological breccia of internally fractured clasts and angular blocks, which correspond to outcropping volcanoes in the upper part of Aconcagua hill ( Aconcagua Volcanic Complex). At the mouth of the Tolosa ravine, a deposit with similar characteristics is observed.
Precisely in the area of Confluence, in the ravine located on the left bank of the Horcones Inferior valley, a profile of approximately 20 meters is presented, where the contact between said grayish gaps and the underlying reddish glacial deposits assigned Aconcagua Climb is clearly exposed. previously by Espizua (1993) to Drift Penitentes. Between Confluencia and the Durazno ravine, the Horcones valley narrows. Here there are only few remnants of lateral moray eels.
The valley of the Horcones river, downstream of the mouth of the Durazno stream, is filled by the deposit here called Horcones. It stands out in the landscape due to its large volume and a very particular surface morphology. The Horcones River is lying on the left bank of the valley, where it carved out a narrow gorge.
The area covered by the Horcones deposit is approximately 6 km2. Although no complete profile is observed in this valley section, unlike what was described for Confluencia, it is estimated that it is probable that the deposit exceeds 30 m thickness throughout most of its area. Climbing Aconcagua According to this, its volume could be at least 180 x 106 m3 for the sector under analysis. Taking into account that there are remains of the deposit from the Horcones Inferior valley, the total volume of the flow must have been even greater.
Its surface morphology is characterized by a succession of elevations and depressions, represented by conical or elongated mounds 5 to 10 m high and between 15 and 30 m in diameter.