PARTITIONING OF STRONTIUM ISOTOPES IN FELDSPARS FROM A PROTEROZOIC SYENITIC MAGMA

2017 ◽  
Author(s):  
Stearns A. Morse ◽  
◽  
S.R. Hart ◽  
Michael J. Jercinovic ◽  
Michael A. Hamilton ◽  
...  
Keyword(s):  
1989 ◽  
Vol 20 (2) ◽  
pp. 85-96 ◽  
Author(s):  
Gunnar Jacks ◽  
Göran Åberg ◽  
P. Joseph Hamilton

Strontium isotopes in precipitation, soil and runoff water can be used to establish a ratio of wet plus dry deposited Sr to Sr released by weathering. This ratio is especially enhanced in areas with old acid Proterozoic rocks (0.6-2.5 Ga) and Archean rocks (>2.5 Ga). Since Sr and Ca behave in an analogous way in the coniferous forest ecosystem the results for Sr can be used for the determination of Ca. If the deposition of calcium can be calculated reasonably accurately the weathering rate can also be estimated. Five catchments have been investigated using this approach. Three of them seem to be close to a steady state, wherein the losses and gains of calcium to the system are equal. In the two southern-most catchments there seems to be an ongoing loss of exchangeable calcium. The loss by runoff occurs with sulphate being the dominant anion. Weathering rates of 1.5 to 4.8 kg Ca/ha year have been estimated.


1968 ◽  
Vol 210 (2) ◽  
pp. 216-222 ◽  
Author(s):  
K. Debertin ◽  
W. Hagedorn ◽  
E. Rössle

1960 ◽  
Vol 38 (12) ◽  
pp. 1614-1622 ◽  
Author(s):  
K. Fritze ◽  
T. J. Kennett

The existence of two new rubidium isotopes, Rb92 and Rb93, has been established and their half lives measured. The half lives of these short-lived fission products were determined using a technique of timed precipitations. The values obtained for Rb92 and Rb93 were 5.3 ± 0.5 sec and 5.6 ± 0.5 sec respectively. The half lives of the strontium and yttrium daughters were also determined. The strontium isotopes were studied by observing the decay rate of a characteristic γ-ray peak. For Sr92, the decay of the 1.37-Mev line gave a value of 2.71 ± 0.02 hr. A γ-ray peak at 590 kev, which was found to be associated with Sr93, decayed with a half life of 7.54 ± 0.06 min. The half lives of the yttrium daughters were determined by β counting. The values found for Y92 and Y93 were 3.53 ± 0.02 hr and 10.1 ± 0.1 hr respectively.


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