The Glaciers of Jan Mayen

Abstract

ABSTRACT. A d escriptive acco unt of the glaciers of Jan M aye n is given, based on th e results o f two recen t Unive rsity of L o ndon exp editions. The positions of most of the glacier snouts are compared w ith previous records and a general advance of th e ice margin is reported . The d iscovery of massive tillite d eposits low d own in the volcanic sequence is thought to confirm the p ost-Pleistocen e origin of the present Beerenberg mountain. An outlin e of th e geological and topographical evolutio n of the mountain is rela ted to the histo ry of its g laciation. Three maj or advances of the ice ma rgin are d escribed, the most recent having taken place within th e last 350 yea rs. Th e tra nsient nature of high-a ltitude rim e structures is d emonstrated. ZUSAMMENFASSUNG. Aui" d er Grund lage d er Ergebnisse zwe ier neuerlic her Expedit ionen d er Un iversity ofLondon wird e ine b eschreibende D a rstellung d el" G le tsch e r von J a n Mayen gege ben. Die Lage d e r m eisten Gle tscherzungen lasst sich mit fruh eren Bericht en verg leic h en , woraus ein a llgem ein er Vorstoss d es Eisrandes zu folgern ist. Die Entdeckung m assiver Tillit-Ablagerungen am unteren E nde el er vulk a nisch e n Schi chtenfolge sch eint elie nach-pl eistoza ne Entstehung eles h eutige n Beerenbergs z u bestatigen. Die geologisch e unel topogra phisch e Entwicklung el es Berges hisst si ch umriss haft mit el er Geschi chte sein er V crglctsch erung verknupfen. Es we rden 3 grossere V orstosse d es Eisranel es b eschri eben , el e re n letz tcr inn erh a lb der letztell 350 Jahre sta ltfalld . Di e Fluchtig keit VOIl R cif-Strukturcn ill g rosser H oh e w irel Il achgew iesen.I NTRODUCTION

Seasonal Weather Trends in Relation to Fluctuations of the Jan Mayen Glaciers Since 1920

“…An ad vance of S0rbreen, the glacier which drains the southern ice field of Beerenberg, Jan Mayen , was first reported by Smith (unpublished), and Kinsman and Sheard (1963) showed this advance to be general, affecting most of the Beerenberg glaciers. The advance of the glaciers has been associated (Lamb and others, 1962 ) with a substantial in crease in annual precipitation over the period 1922-61, for which meteorological data were available.…”

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“…These recent eruptions and flows are an extension of the mode of construction of the island over an estimated 700,000 years. Such additions to the coastline have resulted in the base of preexisting cliffs becoming buried by newer lavas and it is onto this platform that more recent glacier terminal moraines have been deposited, such as at Smithbreen in the northeast of the island (Kinsman and Sheard, 1962). At Kroksletta, near the northern cape, 4,000-year-old moraines that rest on top of an emerged shore platform and beach at 8-10 m above sea level have been buried by subsequent lava flows.…”

“…At Kroksletta, near the northern cape, 4,000-year-old moraines that rest on top of an emerged shore platform and beach at 8-10 m above sea level have been buried by subsequent lava flows. The protruding seaward edge of the Kroksletta lava is now cliffed to a height of 5-13 m (Kinsman and Sheard, 1962). The south part of Jan Mayen is a hilly ridge of scoria craters and mounds and trachyte domes whose lower elevations and older age has produced a coastline of low gradient rocky platforms connected by gravelly beaches.…”

Seasonal Weather Trends in Relation to Fluctuations of the Jan Mayen Glaciers Since 1920

“…L ' avance du S0I'breen d e puis en viron 1954 semble e tre causee par cette rapide augmentation des precipitations, e t aussi par la faibl e diminution des temperatures estivales conside ree neanmoins d e second e importance. Les An ad vance of S0rbreen, the glacier which drains the southern ice field of Beerenberg, Jan Mayen , was first reported by Smith (unpublished), and Kinsman and Sheard (1963) showed this advance to be general, affecting most of the Beerenberg glaciers. The advance of the glaciers has been associated (Lamb and others, 1962 ) with a substantial in crease in annual precipitation over the period 1922-61, for which meteorological data were available.…”