logo SBA

ETD

Digital archive of theses discussed at the University of Pisa

 

Thesis etd-04042016-025929


Thesis type
Tesi di laurea magistrale
Author
MANNELLA, GIORGIO
URN
etd-04042016-025929
Thesis title
Geochemistry and mineralogy of lacustrine sediment from Fucino Lake (Abruzzo, central Italy): palaeoclimatic and palaeoenvironmental implications.
Department
SCIENZE DELLA TERRA
Course of study
SCIENZE E TECNOLOGIE GEOLOGICHE
Supervisors
relatore Prof. Zanchetta, Giovanni
correlatore Dott.ssa Regattieri, Eleonora
correlatore Dott. Giaccio, Biagio
correlatore Wagner, Bernd
Keywords
  • 3
  • 4
  • 5
  • abrupt
  • apennines
  • basin
  • carbon
  • carbonates
  • climate
  • climatology
  • drought
  • environment
  • event
  • heinrich
  • hydrology
  • isotope
  • lago
  • lake
  • mediterranean
  • mis
  • multi
  • oxygen
  • palaeo
  • paleo
  • precipitation
  • proxy
  • region
  • tephra
  • tephrochronology
Graduation session start date
22/04/2016
Availability
Full
Summary
Fucino basin is the largest intermountain tectonic depression of the central Apennines (Abruzzo, Italy). It hosts a thick and continuous succession of fine-grained lacustrine sediments interbedded with several fall-out deposits from the pery- Tyrrhenian Quaternary volcanic centres. In co-operation with international scientific partners (CNR-IGG of Pisa, Institut für Geologie und Mineralogie of Cologne, School of Earth Sciences of Melbourne) we performed multi-proxy geochemical analyses (XRF scanning for Si, K, Ca, Ti, Mn, Fe, Rb, Sr and Zr; total organic carbon, TOC; total inorganic carbon, TIC; total nitrogen and sulphur; oxygen and carbon stable isotopes) on a long core (87 m) retrieved from the Fucino basin in June 2015. On the basis of a tephrostratigraphic age-model developed at the CNR-IGAG in Rome the core span continuously between ca. 3000 and 160,000 yr. In this thesis we investigated an interval constrained between two Latium tephra layers corresponding to the 84.6 ± 5.1 and 36.2 ± 1.6 ka time-span. This period of time covers basically the ignition of the last glaciation (the transition between MIS5 and MIS4 in the marine isotope scale) and part of the last Pleniglacial period which was characterised by abrupt climatic and environmental changes on both global and regional scale.
From time series of our proxy data we recognised complex low frequency trends with superposed higher frequency oscillations. We interpreted observed variations in terms of palaeohydrological and palaeoenvironmental changes in the lake catchment. On the basis of the most significative proxies (Ti, Ca, TOC%, TIC%, δ18O) we divided the record into three different periods: the first spanning between 85 and 68 ka, the second between 68 and 50 ka and the third between 50 and 36 ka.
In our interpretation, the first period was characterised by low minerogenic input, high lake primary productivity and an enhanced precipitation. The second period had generalised high minerogenic input and low lake primary production, although it was mainly characterised by high-frequency and high- amplitude oscillations suggesting high frequency environmental instability.
The beginning of the third period is marked by an abrupt increase in minerogenic input and by a prominent decrease in lake primary production. Overall, minerogenic input was high and lake productivity low. This period was mainly characterised by rather stable environmental conditions which were supported by less intense and abrupt variations in the hydrological regime. The last 2-3 ky of our record displayed a restoration of high-frequency and high-amplitude oscillations.
By comparing our record with other regional (Monticchio Lake pollen record) and external (North Atlantic marine cores, Greenland ice cores) climatic archives and with Northern Hemisphere insolation curves we recognised a strong climatic coherence at a regional scale. We interpreted the 84,6-68 ka period as representative of late MIS5 interglacial conditions, the 68-50 ka period as representative of the onset of MIS4 fully glacial conditions and the 50-36 ka period as representative of MIS3 mild glacial conditions over the Western Mediterranean basin. Rapid oscillations in the hydrological regime over the lake catchment and in soil erosion rates can be regarded as the expression of Heinrich events and DO events, recognised in the North Atlantic, over the Mediterranean.
File