Geological researches carried out near the Castagnone hamlet in the Cerrina Valley (Northern Monferrato Hills, Piedmont, NW Italy) have brought to light a post-Messinian succession whose sedimentary record starts with a Lower Complex of pedogenized colluvial materials, followed upwards by two superimposed Alluvial Units (I and II). The lower one of these units has yielded a few Galerian macrofaunal remains but in association with arvicolid teeth of Early Biharian (Rodent) Age, while the upper one, due to own major soil weathering, could yield only poor, not diagnostic fossil remains. Both fluvial units were deposited during a normal palaeomagnetic phase. The I Alluvial Unit, allowing for the biochronological correlation, must be referred to the Jaramillo Subchron, between 1.070.000-990.000 years ago. The II Alluvial Unit being both uncomformable with, and younger than, the first one, might be best referable to the Brunhes Chron. The dipping of the beds throughout the reported succession shows, also, a progressive syn-sedimentary tilting with accelerated deformation during the I Alluvial Unit deposition. Such a tectonic stress over the Castagnone area is seemingly related to the uplift of the north-easternmost ridge of the Monferrato Hills, and it appears to have been nearly exhausted before the II Alluvial Unit deposition.
The Castagnone site (Cerrina Valley, Monferrato Hills, NW Italy): Early Pleistocene Sedimentary Record and Biochronology.
MOTTURA, Alberto;SIORI, Maria Stella;
2003-01-01
Abstract
Geological researches carried out near the Castagnone hamlet in the Cerrina Valley (Northern Monferrato Hills, Piedmont, NW Italy) have brought to light a post-Messinian succession whose sedimentary record starts with a Lower Complex of pedogenized colluvial materials, followed upwards by two superimposed Alluvial Units (I and II). The lower one of these units has yielded a few Galerian macrofaunal remains but in association with arvicolid teeth of Early Biharian (Rodent) Age, while the upper one, due to own major soil weathering, could yield only poor, not diagnostic fossil remains. Both fluvial units were deposited during a normal palaeomagnetic phase. The I Alluvial Unit, allowing for the biochronological correlation, must be referred to the Jaramillo Subchron, between 1.070.000-990.000 years ago. The II Alluvial Unit being both uncomformable with, and younger than, the first one, might be best referable to the Brunhes Chron. The dipping of the beds throughout the reported succession shows, also, a progressive syn-sedimentary tilting with accelerated deformation during the I Alluvial Unit deposition. Such a tectonic stress over the Castagnone area is seemingly related to the uplift of the north-easternmost ridge of the Monferrato Hills, and it appears to have been nearly exhausted before the II Alluvial Unit deposition.
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