A Gravity Survey of the Melville Island Ice Caps

Abstract

ABSTRACT. A gravity survey was made in June o f 1963 of four ice caps on western M e lv ille Island, Ca nadia n A rct ic Archipelago. I ce thicknesses were interpreted from Bou g u e r anomalies at 138 stations. Th e regional g ravity fi eld of the area has a simple form and is associaled with a uniform bedrock geology. Because of this, the inte rpretation of th e g rav ity d ata was g rea tly simplifi ed in compa rison with th e more usual glaciologica l problem. It was found that greatest ice thi ckn esses ranged from 30 to 50 m., fillin g hidden valleys or d epressions under th e main ice-cap bod y. I ce-cap vo lumes ranged from 0·2 to 1·0 km .l. REsUME. L eve gravimitrique des ca/olles de_glace de l'!le de M e/ville. Un leve g ravimetrique a ete effectue en juin 1963 des quatre calottes d e g lace de I'I le de Melvill e ouest, Archipe l A rc tiqu e Canadien . L 'e pa isse ur de la g lace a e te d ed uite des a nomalies d e Bouguer en 138 stations. Le champ d e gravite regional d e la zo ne e tudiee a un e form e simple et il es t assoc ie it la geo log ie uniforme du socle roc he ux. Ainsi , l' inte rpre tation d es m esures gravimetriques a ete g rand e m e nt simplifiee e n compa ra ison d es probl emes glacio log iqu es courants. II a ete trouve que la plus grande epa isseur de glace se tena it entre 30 e t 50 m , rem plissant d es vallees et d epressions cachees so us I'e nsembl e de la ca lolte d e g lace. L es volumes d es calottes de glace sont compris entre 0,2 et 1,0 km l .ZUSAMMENFASS NG . SchweremessllIIOen azif den Eiska/J/Jen von M elville Island. I m J uni 1963 wu rde n Schwerem essunge n a uf vie r Eiskappen im westli chen Melv ill e I sla nd , Ka nadi sche r Arktis-Archipel, durchgeflihrt. Dic Eisdicke wurde a us Boug uer-An oma li en a n 138 Statio nen abgeleite t. D as reg iona le Schwe rkra ftfeld hat e infache F orm , herrlihrcnd vom g le ichfiirmigen geo log ischen Aufbau des U nl ergrundes. D esha lb vereinfachte si ch im V ergleich ZlI dem so nst vorli egenden g laz io logischen Pro b le m di e Interpretatio n d er Schwerkraftwerte we itge he nd . Als griisste E isdic ken wurd en W erte zw ischen 30 und 50 m gefunden ; sie treten auf liber T a lern oder V erti efun gen, di e si ch unter d er H a uptm asse der Eiskappe n verberge n. Das Vo lumen d er Eiskappen li eg t zwisehen 0 , 2 und 1, 0 km l . THE GRAVITY S URVEYTh e general loca tion of the ice caps is shown in Figure I ; they are d esignated as "North ", " W est", "Eas t" and "South " ice cap according to th eir rela tive positions. Approximately ellipti cal in shape, the ice caps lie on the dissected plateau which is th e prin cipal topographic form of west Melvill e Isla nd. Th e ice caps range in a rea fr om 15 to 55 km.' and li e at an average eleva tion of 550 m.The objectives of the gravity survey, performed inJune 1963, w er e to find the gen eral form of the ice bodies and to determine the locations of greatest ice thickn ess, su itable for a future bore hol e for glacio logical a nd h ea t-flow studi es . Th e survey was...

Revisiting Austfonna, Svalbard, with potential field methods – a new characterization of the bed topography and its physical properties

“…Gernigon et al, 2018;Døssing et al, 2016;Nasuti et al, 2015;Gernigon and Brönner, 2012;Olesen et al, 2010;Barrère et al, 2009) and for sea ice and glacier studies (e.g. An et al, 2017;Gourlet et al, 2015;Tinto et al, 2015;Zhao et al, 2015;Porter et al, 2014;Tinto and Bell, 2011;Studinger et al, 2008Studinger et al, , 2006Spector, 1966). In this study, we combine these methods with GPR data to obtain both an accurate glacial bed topography and also an understanding of the rheological changes of the basement.…”

Revisiting Austfonna, Svalbard with potential field methods – A new characterization of the bed topography and its physical properties

“…Gravity and magnetic methods have been used independently in the past for basement studies in the Arctic and other glaciated areas (e.g. Gernigon et al, 2018;Døssing et al, 2016;Gourlet et al, 2015;Nasuti et al, 2015;Gernigon and Brönner, 2012;Olesen et al, 2010;Barrère et al, 2009;Spector, 1966). In this study, we combine them with GPR data to obtain both an accurate glacial bed topography and rheological changes of the basement.…”