ABSTR ACT. The M cMurd o I ce Shelf a nd assoc iated faun a l rem a ins were exa mined in th e vicinity of th e easternmost D a iley Isla nd. Stra tig ra phi c, petrographi c, a nd chemical compos ition studi es of cores from two holes drilled through th e ice sh elf show th a t at th ese loca tions th e sh elf is composed onl y of fr esh-wa ter ice. Althoug h cores from the d eep e r h ole possessed typi call y glacial tex tures th ro ughout, m u ch of th e ice from this part of the M cMurdo I ce Shelf may have bee n fo rmed from th e freez ing of a layer of fres h wa ter found sandwich ed b e tween shelf b o tto m and th e und erl y ing sea-water . T he existen ce of fresh wa te r under the ice shelf ca n m ost proba bl y be a ttributed to dra inage o f surface melt wa te r during the ab la tio n season. Ther e wa s no eviden ce to indi cate that this pan of th e M c Murdo I ce S helf is b e in g nourished by th e g rowth of sea ice onto its lower surface. Th e fis h rema ins fo u nd o n the ice surface were confin ed to a n a r row zone along the tide c rack and a re beli eved to have been left in t hi s vicinity by d eep di v in g seals. Th e marine in vertebra te rema in s on top of the ice are associa ted with m o ra ina l m a teria l a nd a re b el ieved to have b een incorporated into th e ice at the time of fo rma ti on of th e mora ines. R ESU ME . .NollveLle Iwniere sllr le mode de remolltee de poissoll et morailles dJossiles £lit M cM llrdo Ice Shelf, Alltarctiqlle.Le M cMurd o I ce Shelf et Ies re liquats associes de fa un e ont ete exa min es d a ns le voisin age d e l' il e la plus it l'est d es Dailey I sla nds. D es etu des stra tigraphiques , pet rog raphiqu es e t d e compositio n c himi q ue d e ca rottes provena nt d e d eux forages it trave rs le ice shel f m o nu'e nt q ue, it ces sta tio ns, le ice shelf es t co mpose uni quemen t d e g lace d ouce. Bi en q u e les ca rOttes du b as du trou de fo rage p ossed ent tout a u lo n g d es tex tures glacia ires typiques, la plus g ra nd e pa ni e de la g lace d e cette pa rtie du M cMurdo I ce S he lf a pu se form er pa r le gel d ' une strate d'eau d o u ce sa isie entre le bas d u shelf et I'eau d e m e r sous-j acent e. L 'ex istence d 'ea u douce sous le ice shelf peut le plus proba blement e lre a ltribuee a u dra inage d e l'ea u d e fu sio n superfi ciell e penda nt la saison d 'abla li on . 11 n 'y avail a UCLln e ev ide nce en faveur d' un e cro issance pa r g lace d e mer SLlr la surface infer ieure de cett e par ti e d u M cMLlrdo I ce S h elf. Les rel iqua ts d e p o isson trou ves sur la surface de la glace etai ent confines it une zon e c tro ite le long d es c reva sses de ma ree e t I'on p ense q u' il s y ont e te a ba ndonn es par d es phoques chassa nt it g ra nd e profond eLlr. L es rc1 iqua ts d ' in ve rt e bres m a rins a u sommet d e la glace sont associes a vec du mat eri el mo ra ini q ue, et 1'0n pense qu ' ils ont ete in co rpo res it la glace lors d e la fo rma tion d es lTIora in es. Z USAMM EN FASSUNG . .Neues L i...
The McMurdo Ice Shelf and associated faunal remains were examined in the vicinity of the easternmost Dailey Island. Stratigraphic, petrographic, and chemical composition studies of cores from two holes drilled through the ice shelf show that at these locations the shelf is composed only of fresh-water ice. Although cores from the deeper hole possessed typically glacial textures throughout, much of the ice from this part of the McMurdo Ice Shelf may have been formed from the freezing of a layer of fresh water found sandwiched between shelf bottom and the underlying sea-water. The existence of fresh water under the ice shelf can most probably be attributed to drainage of surface melt water during the ablation season. There was no evidence to indicate that this part of the McMurdo Ice Shelf is being nourished by the growth of sea ice onto its lower surface. The fish remains found on the ice surface were confined to a narrow zone along the tide crack and are believed to have been left in this vicinity by deep diving seals. The marine invertebrate remains on top of the ice are associated with morainal material and are believed to have been incorporated into the ice at the time of formation of the moraines.
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