Mineraloške, geokemijske i pedofizikalne značajke poligenetskog tla razvijenog na kasno glacijalnom lesu (OIS 2) otoka Suska

master's thesis

• Title: Mineraloške, geokemijske i pedofizikalne značajke poligenetskog tla razvijenog na kasno glacijalnom lesu (OIS 2) otoka Suska : diplomski rad
• Title (english): Mineralogical, geochemical and pedophysical properties of polygenetic soil developed on late glacial loess (OIS-2) on the island of Susak : master's thesis
• Author: Matko Patekar
• Mentor: Goran Durn (mentor)
• Committee member: Goran Durn
• Committee member: Marta Mileusnić
• Committee member: Stanko Ružičić
• Granter: University of Zagreb; Faculty of Mining, Geology and Petroleum Engineering; (Department of Mineralogy, Petrology and Mineral Resources); Zagreb
• Defense date and country: 2015-09-30, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Geology; Mineralogy and Petrology

Abstract

Cilj ovog istraživanja je odrediti mineraloške, geokemijske i pedofizikalne značajke poligenetskog tla razvijenog na kasno glacijalnom lesu otoka Suska. Uz navedene značajke, cilj je istražiti starosti dvaju lesnih horizonata koji se nalaze unutar istraženog profila tla. Les je klastični eolski sediment, kontinuirano taložen tijekom hladnijih dijelova pleistocena, i vrlo je ovisan o klimatskim uvjetima te je stoga izuzetno zanimljiv pri paleoklimatskim rekonstrukcijama kvartarnog perioda. U svrhu prikupljanja uzoraka i podataka, u travnju 2014. godine organiziran je terenski rad u trajanju od pet dana na otoku Susku, te je detaljno istražena i uzorkovana lokacija “Svjetionik” koja predstavlja gornji (najmlađi) dio lesne sekvence. Obzirom da sva (paleo)tla unutar lesnih naslaga sadrže sekundarne pedogene karbonate koji djelomice „maskiraju“ pedogene procese koji su bili aktivni tijekom nastanka (paleo)tla, nužno je bilo pronaći i istražiti beskarbonatno recentno tlo. Terenskim istraživanjima detaljno su opisana morfološka svojstva svih horizonata u poligenetskom tlu. Laboratorijskim istraživanjima utvrđene su geokemijske, fizikalno-kemijske, granulometrijske i mineraloške karakteristike lesa i poligenetskog tla. Starosti sedimentacije lesnih horizonata određene su pomoću infracrveno stimulirane lumisiscencije (IRSL). Na temelju rezultata terenskih i laboratorijskih istraživanja napravljena je detaljna rekonstrukcija procesa koji su uvjetovali nastanak istraženog poligenetskog tla. četri bitna zaključka proizašla su iz ovog rada.
(1) Istraženo tlo je poligenetsko. Dokaz tome su dva lesna horizonta te razvijeno paleotlo Bb, nastalo iz lesnog matičnog materijala koji više nije prisutan u tlu.
(2) Utvrđeni su do sada najmlađi istraženi lesni horizonti na otoku; starost lesa u podlozi poligenetskog tla je ~16 000 godina i pripada OIS-2 stadiju, a starost lesa najbližeg površini je ~3 000 godina.
(3) Na temelju geokemijskih i mineraloških istraživanja jasno je izdvojen horizont paleotla Bb u kojem prisustvo klorit-vermikulita indicira na znatno trošenje primarnih filosilikata. Također, visoke vrijednosti CEC-a, Fed / Fet i CIA dokazuju da je horizont Bb najviše izmijenjen u pedogenetskom smislu.
(4) Prisustvo lesa, paleotla i tla u istom profilu (poligenetsko tlo) dokazuje kako je generalno topla i vlažna klima trenutnog interglacijala bila isprekidana hladnijim periodima sa jačim vjetrovima. Na temelju elementarne geokemije, uspoređeni su današnji klimatski trendovi (temperatura, precipitacija) sa onima u vrijeme formiranja tla.

Abstract (english)

Abstract: The subject of this thesis is to identify mineralogical, geochemical and pedophysical properties of polygenetic soil de-veloped on late glacial loess on the island of Susak. In addition to this, the purpose was to determine the age of two loess hori-ozons within the investigated soil profile. Loess is clastic aeolian sediment, usually accumulated during the colder periods of Pleistocene. Since loess is particularly dependant on climatic conditions, it is being widely used as a proxy in Quaternary paleo-climatic reconstructions. In April 2014. a five day field work was organised on the island of Susak with the purpose of sampling. The focus was put on the top part of Susak loess sequence, and location ”Svjetionik” (Lighthouse) was investigated in detail. Since most of the paleosols within loess sequence contain secondary pedogenetic carbonates, which could “conceal” certain pedogenic processes, it was necessary to find a carbonate-free soil. During field work, morphological properties of soil horizons were investigated. Based on field and laboratory investigations we concluded that soil situated on the top of loess sequence repre-sents polygenetic soil. Chemical, physical, geochemical, granulometrical and mineralogical properties of loess and polygenetic soils were determined. Loess sedimentation age was determined by infrared stimulated luminescence (IRSL). Investigated prop-erties of loess and polygenetic soil allowed a detailed reconstruction of pedogenic processes which formed the investigated poly-genetic soil. Four important conclusion came out from this thesis.
(1) Investigated soil is polygenetic. Two loess horizons and developed paleosol horizon Bb (whose parent loess material is no longer present in soil) clearly point out the polygenetic nature of investigated soil.
(2) Stratigraphically youngest loess horizons were determined. Determined age of loess located at the base of polyge-netic soil is ~16 000 ka, belonging to OIS-2, while overlying younger loess is ~3 000 ka old.
(3) Geochemical and mineralogical properties clearly singled out paleosol horizon Bb, in which presence of chlorite-vermiculite indicates substantial weathering of primary phyllosilicates. Furthermore, high values of CEC, Fed / Fet and CIA clearly point out that Bb paleosol has undergone the most significant pedogenic change.
(4) Presence of loess, paleosol and modern soil in the polygenetic soil profile indicate that generally warm and humid climate of actual interglacial was interrupted with colder and drier periods with stronger winds. Using elemental geo-chemistry, a comparison between modern and past climate conditions (temperature and precipitation) was made

• Keywords: les; paleotlo; poligenetsko tlo; kvartar; klimatske oscijacije; pedogeneza; kvantitativna paleo-pedologija; luminiscencija; paleoklimatska rekonstrukcija; otok Susak
• Keywords (english): loess; paleosol; polygenetic soil; Quaternary; climate oscillations; pedogenesis; quantitative paleopedology; lumi-nescene dating; paleoclimatic reconstruction; island of Susak
• Language: croatian
• URN:NBN: urn:nbn:hr:169:185008
• Study programme: Title: Geology; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra geologije (magistar/magistra geologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2015-12-18 08:57:58