ARCTIC Late Weichselian. Glacial Geology of the Lower Borgarfjordur Region

• Main Author: Olafur Ingolfsson
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Arctic; Maurice; Melabakkar; glacier; Iceland
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.496.7556; http://pubs.aina.ucalgary.ca/arctic/Arctic38-3-210.pdf

ABSTRACT. Morphological and lithostratigraphical investigations have,revealed two successive glacial advances of Late Weichselian age in the lower Borgarfjordur region, Western Iceland. Studies of the Melabakkar-Asbakkar coastal cliffs have disclosed a complex of glaciomarine sediments ’ and tills, accompanied by glaciofluvial deposits from ice marginal sources. A brief description is given for each of the major lithostratigraphical units, and a depositional model for the sequence is outlined. The first glacial advance occurred some time shortly after 12 OOO radiocarbon years before present (BP), and the second one around 11 OOO BP. By 10 OOO BP the glaciers had retreated from the lowlands and the sea transgressed to 60 m above present sea level, where extensive marine terraces were formed. Key words: Borgarfjordur, western Iceland, Melabakkar-Asbakkar, glacial geology, glacial chronology, Late Weichselian RESUME. Des etudes morphologiques et lithostratigraphiques ont signal6 deux crues de glaciers du Weichsel superieur dans le sud de la region Borgarfjordur, dans I’ouest de I’Icelande. Des etudes des falaises cdtitres Melabakkar-Asbakkar ont mises?t jour un complexe de s6diments et de moraine de fond glaciomarins accompagnks de d6p6ts glaciofluviaux provenant des extrCmit6s de glaciers. Chaque unite lithostratigraphique impor-tante est britvement d6crite et un modble du dkp6t est expos6 dans ses lignes g6nbrales. La premitre avance de glacier se deroula peu aprks le XIIe millenaire (au carbone 14) avant notre kre, et la deuxikme, vers le XIe millenaire avant notre tre. Les glaciers s’6taient retires des terres basses avant le Xe millknaire avant notre kre et la mer avait monte?I 60 m au-dessus du niveau actuel de la mer, formant d’importantes terraces marines. Mots cl6s: Borgarfjordur, ouest de I’Icelande, Melabakkar-Asbakkar, geologie glaciale, chronologie glaciaire, Weichsel superieur Traduit pour le journal par Maurice Guibord.