Holocene environmental changes in the central highlands of Iceland as recorded in soils

• Main Author: Sigurveig Gunnarsdóttir 1994-
• Other Authors: Háskóli Íslands
• Format: Thesis
• Language: English
• Published: 2018
• Subjects: Jarðfræði; Jarðsaga; Jarðvegur; Rof; Loftslagsbreytingar; Jarðlög; Kjölur; Rannsóknir; Arnarvatn; Arnarvatn-Stóra; Hvítárvatn; Langjökull; Iceland
• Online Access: http://hdl.handle.net/1946/31875

Across the central highlands of Iceland soil sections are accessible in rofabörð were they can reach back to the time of initial soil formation after the deglaciation around 11.5 ka. These soil sections have been used to reconstruct tephrochronology and also to study soil erosion in Iceland. The main focus of this project is to study soil sections by Kjölur for the purpose of reconstructing the environmental and climate changes that have occurred during the Holocene with the help of tephrochronology and geochemical researches. Five soil sections were in total measured and samples collected for studying carbon content as well as for the branched glycerol dialkyl glycerol tetraether (brGDGT) paleothermometer to estimate temperature changes for the Holocene. Numerous tephra layers can be found in the soil sections which were identified to their volcanic source and age which made it possible to obtain age models for each section. By identifying the tephra layers it was also possible to correlate between sections and calculate the soil accumulation rate for each section. By interconnecting the results from the identification of tephra layers, calculation of soil accumulation, carbon content and the brGDGT it was possible to reconstruct environmental and climate changes for the area and compare the results to similar studies that have been done on sediment from Hvítárvatn by Langjökull and Arnarvatn Stóra. The main results of studying the soil sections reflect the results from the lake studies and indicate that a gradual cooling has been occurring for the last 10 ka superposed by more stepped changes at 8.2, 6.0, 4.4, 2.7, 1.4 and 0.6 ka when increased soil erosion took place. Soil erosion was most active during the Little Ice Age (LIA 1300-1900 CE) when soil accumulation rate was highest in the sections located furthest to the southwest in the research area. This indicates that strong northerly winds were dominant during that time. Although a brGDGT temperature calibration of Icelandic soils is yet to be developed to ...