High-resolution environmental proxies from the southern central Apennines (Molise Region) are essential to understand past climatic changes in the late Pleistocene-Holocene. The aim of this PhD thesis is to enrich our knowledge of the outcropping fluvial-lacustrine succession in two intermontane basin, located in the southern Apennines (Italy). The first basin studied is located in Matese pedemontane area and consists of alluvial and fluvial-lacustrine sequences of about 11 m in detpth. The study area consists of top soil and several clastic sedimentary levels alternated with four layers of paleosols and clastic sediment layers. Present-day soils consist of well-developed Andosols. Soil and paloesols were analyzed with laser grain size distribution (GSD), geochemical and magnetic properties in order to evaluate the relative contributions of pedogenic and/or detrital components. The results showed that the finest pedogenic ferrimagnetic grains in the clay fraction exhibit two trends with respect to the degree of pedogenesis. The paleosols sequence was composed of highly-weathered Vertisols (Solum I and IV) and of less weathered Entisols (Solum II and III ) intercalated in the clastic sedimentary levels. A greater pedogenetic degree occurs in Vertisols (Solum I), with high clay content, which developed under temperate climates and formed below the layer of Neapolitan Yellow Tuff (12 ky BP). Solum II and III show a low magnetic degree of fine fractions, consistent with a low rate of pedogenesis, could have developed under more cold humid climatic conditions after the last eruption (Campanian Ignimbrite, 39 ky BP). Solum IV is characterized by a greater pedogenetic intensity associated with high value of magnetic susceptibility. The second intermontane basin was located in the north-east part of the Molise Region, in Montenero Valcocchiara village. Up to now, no systematic pedologic and paleoenvironmental studies have been carried out in the peat bog, that is located in this basin. Therefore, high-resolution and systematic magnetic studies combined with geochemical, palynology and mineralogy data were carried. Based on these data, the peat bog sequence can be separated into 3 units. Unit 1 (0–199 cm, 2-3 ky BP) shows high organic matter content, pyrite and some anthropogenic trace elements. Low magnetic susceptibility (χ) degree suggests that detrital input signals was due to effects of anaerobic dissolution processes. This Unit contains pollen of aquatic plants of lacustrine environment (Potamogeton) and cereals. For Unit 2 (200–300 cm, 3-5 ky BP), magnetic measurements increase and the corresponding concentration of ferrimagnetic minerals is also improved, besides this unit was characterized by increasing percentages of cereals pollen (graminaceae). For Unit 3 (300–400 cm, 5-7 ky BP), the bulk magnetic properties are dominated by detrital (calcium carbonate) sediments, correlated with Fe and Ti content. There was a significant change in arboreal taxa of deciduous trees towards Abies alba presence. In conclusion, combination of magnetic properties, trace elements, and other proxies provide a viable framework for reconstructing the paleoenvironmental changes of this lacustrine sequence during the middle of the Holocene period (6 ky BP).
|Titolo:||Suoli e peleosuoli tardo Pleistocenici-Olocenici in sequenze fluvio-lacustri della regione Molise|
|Altri titoli:||Late Pleistocene-Holocene soils and paleosols in fluvial-lacustrine sequences in Molise region|
|Data di pubblicazione:||26-mar-2015|
|Appare nelle tipologie:||8.2 Tesi di dottorato (Ex-ROAD)|