Massive sulfide samples from the Bent Hill area were analyzed for 230Th/234U and 231Pa/235U disequilibria. Apparent ages calculated from these ratios are between 8.2 and >300 ka. Concordant ages were found for only three samples that originate near the surface from the clastic sulfide zone and suggest "true" ages of between 8.5 and 16.0 ka (mean of 230Th and 231Pa ages). The uranium vs. depth distribution in the Bent Hill Massive Sulfide deposit suggests an open system for uranium for the deeper part of the deposit, which was probably caused by extensive recrystallization processes inhibiting true age determinations.
1Scholten, J.C., Lackschewitz, K.S., Marchig, V., Stoffers, P., and Mangini, A., 2000. 230Th/234U and 231Pa/235U disequilibria in massive sulfides from the Bent Hill area (Legs 139 and 169). In Zierenberg, R.A., Fouquet, Y., Miller, D.J., and Normark, W.R. (Eds.) Proc. ODP, Sci. Results, 169 [Online]. Available from World Wide Web: <http://www-odp.tamu.edu/publications/169_SR/chap_04/chap_04.htm>. [Cited YYYY-MM-DD]
2Institut für Geowissenschaften, Olshausenstrasse 40, 24118 Kiel, Federal Republic of Germany. Correspondence author: js@gpi.uni-kiel.de
3Bundesanstalt für Geowissenschaften, Stilleweg 2, 30655 Hannover, Federal Republic of Germany.
4Akademie der Wissenschaften, Im Neuenheimer Feld 366, 69120 Heidelberg, Federal Republic of Germany.
Date of initial receipt: 1 March 1999
Date of acceptance: 3 November 1999
Date of publication: 30 June 2000
Ms 169SR-108