TEMPERATURE AND UPLIFT HISTORY OF BJORNOYA (BEAR-ISLAND), BARENTS-SEA

Apatite fission track age data from the majority of the 14 samples stu died indicate cooling below c. 110 degrees C beginning 60 to 90 Ma ago . Vitrinite reflectance modelling suggests temperatures prior to cooli ng reached > 160 degrees C in the north and 150 to 160 degrees C elsew here. Temperatures from fluid inclusions in quartz cement from the Car boniferous Nordkapp Formation may have reached 139 to 151 degrees C. Z ircon fission track data from the basement indicate that the maximum t emperature during Hecla Hoek metamorphism was less than 290 degrees C. Circumstantial evidence suggests that temperatures prior to depositio n of the Permian Miseryfjellet Formation were probably much lower than those during the Mesozoic. Maximum eroded overburden above the Misery fjellet Formation can be estimated at 2900 to 4200 m using various dif ferent methods. The resulting geothermal gradients suggest palaeoheat now conditions close to those of today.