WPC 2 B P Z Courier 10cpi #| x I x @ 8 ; X @ HP LaserJet IIID HPLASIII.PRS x @ , , MX @ #| x 2 Z B X F : HP LaserJet IIID hange HPLASIII.PRS x @ , , MX @ 2 x x x , x @ 8 ; X @ l j $ H H H , ) H | @ ; @ . } * d d d , $ d @ 8 ; @ H < ! , 2 , < P 7 , P Courier 10cpi Line Printer 16.67cpi Courier 12cpi CG Times (Scalable) " m ' ? ^ !.22YN!!!2Y!!!!2222222222!!dYd,YH?EJ?;HJ!'F? JH9HC6?JH^HHA!!!22!,2,2,!22 2 N2222%' 22H22,,2,d ! 22 222!!!! 222222 222 H,H,H,H,H,YCE,?,?,?,?,! ! ! ! J2H2H2H2H2J2J2J2J2H2H,J2H2H2H2J292H,H,H,E,E,E,E,J2?,?,?,?,H2H2H2H2H2H2J2J2! ! ! ! I8' F2? ? ? ? ? J2J;J2J2H2H2YHC%C%C%6'6'6'6'? ? ? J2J2J2J2J2J2^HH2A,A,A, J2? J2C%6'? H2H2J2H2J2 ! 22 ! !!/ddddddddddddddddddddddddddddddddddddddddddddddddNHHH2 22!,))22X222YY2#2222Y# !! 442Y dd22==Ld2d2H2 ;SS88Y !4 2 ^ x #"ddddHHddd2Hdd4HHYYddd 2ÕYYddd Y2!!dddddH=dYHHHHHHHHHHx!d2H282YdHdC2!2H,29HNAddHHHHHHHHHHddddd.dHHHHddddddddddddd ddddddHHddddddSC=NdHd dd +; HHHH dd d dd d HHH2HHdHHddd HH H, HHHH, HHHHH HHH HHH HHH HHHHHHHHHHHHHH H HHHHHH HHHHHHHH! HHH! HHH! HHH! HHHH H H HHHH HHH H=?8 =8C,?'A,J2H,! F,C8 8J,C2H,H=92=2 2?,H,C=H8N===='2 ,,,=,= = == !!22222 22 ==================='''''''22222222222222222222 ,,,,,,,,,,,,,,,,,,,====================! 9 H?J!HH=!H2 2,! x 2 9313865 FARLEY Lavas of hot spot volcanic chains, e.g., Hawaii, have long been 2 known for their unusually high 3 HE/ 4 He ratio; and a straightforward interpretation of this ratio is that these lavas must tap a rather undifferentiated part of the mantle (meaning a portion of the mantle that has remained exluded from all the plate tectonics related differentiation of the earth since its birth). However, intuitively, those explanation was very hard for a fair number of scientists to swallow because it is hard to imagine how He and Ne, rare gases, would remain so isolate in an ever differentiating and evolving earth when all other isotopic systems and elements have been disturbed. Don Anderson (CIT) has now challenged this concept 2 in the latest issue of Science and argued that the high 3 He in the mantle source of the hot spot basalts may be seeing a subducted sedimentary component that contains extraterrestrial rare gases incorporated in tiny dust particles. In order to test this iconoclastic idea, the PI has formulated a simple but elegant test, namely to analyze old 0 80 million years) sedimentary cares from the oceans for these isotopes. His objective is to evaluate whether the results are negative or positive, will have great impact on our understanding of geochemical reservoirs in the earth's mantle, cosmic fluxes of materials to the oceanic sediments, and the importance of subducted sedimentary component in oceanic island volcanism. ***
