Calculation Program for Isochron Ages of Rb-Sr and Sm-Nd Systems Using Personal Computer

Abstract

Calculation program for isochron ages of Rb-Sr and Sm-Nd systems based on York (1966) is presented. This paper discusses calculated method and its BASIC program. The program is approved by test data, spread sheet program and published data. In conclusion , calculated results by the program is sufficiently confided. 1.‚Í ‚ ¶ ‚ß ‚É ‹ß "N,'n ‹…‰È Šw‚Ì •ª-ì ‚É‚¨‚¢‚É‚¨‚¢ ‚Ä"¯ ˆÊ 'Ì ƒf •[ ƒ^ ‚Í •K-v •s ‰Â OE ‡‚È ‚à ‚Ì ‚É ‚È ‚Á‚Ä‚¢ ‚é.ˆê "Ê ‚ÉRb-Sr,Sm-NdOEn ‚È ‚Ç ‚Ì "¯ ˆÊ 'Ì "ä ‚Ì 'ª 'è ‚Í 'å •Ï ‚ȘJ-Í‚AE"ï-p‚ð •K-v‚AE‚µ,OEÀ ‚ç ‚ê ‚½ OE¤‹ † ‹@ŠÖ‚Å‚Ì ‚Ý•ª •Í ‚ª ‰Â "\ ‚Å‚ ‚é."ú-{ ‚Å ‚Í1980"N 'ã OEã"¼ ‚© ‚ç Še 'å Šw •E OE¤‹ † ‹@ŠÖ‚ÉŽ¿-Ê •ª •Í OEv‚ª •Ý'u ‚³ ‚ê ‚Í ‚ ¶‚ß,•ª •Í ‹Z •p ‚Ì OEü•ã ‚AE‹¤ ‚É'½ ‚-‚Ì "¯ ˆÊ 'Ì ƒf •[ ƒ^‚ª OEö •\ ‚³ ‚ê ‚Ä ‚«‚½. ‚± ‚ê ‚ç ‚Ì "¯ ˆÊ 'Ì ƒf •[ ƒ^‚Ì •â •³ •E•ˆ-•‚Í •¡ ŽG‚È‚½‚ß ‚É ƒRƒ" ƒs ƒ… •[ ƒ^ ‚ð-p‚¢ ‚Ä•s ‚í ‚È ‚¯ ‚ê ‚Î ‚È ‚ç ‚È‚¢.•• 'Ê ,Ž¿-Ê •ª •Í OEv ‚É ‚Í ƒRƒ" ƒs ƒ… •[ ƒ^‚ª •t '® ‚µ ‚Ä‚¨‚èƒf‚Ä‚¨‚èƒf •[ ƒ^‚Ì •ˆ-•‚à-e ˆÕ ‚É ‚Å ‚« ‚é ‚ae ‚¤ ‚É ‚È ‚Á‚Ä‚¢ ‚é ‚ª,ˆË 'R "Ï ŽG‚ÈOEvŽZ‰ß 'ö ‚ð "¥ ‚Þ ‚à ‚Ì ‚ª Žc ‚³ ‚ê ‚Ä‚¢ ‚é.‚» ‚ê ‚ÍRb-Sr,Sm-NdOEn ‚È ‚Ç ‚ð Žg ‚Á‚½ "N'ã 'ª 'è ‚É‚¨‚¯‚É‚¨‚¯ ‚é ƒAƒCƒ\ ƒNƒ• ƒ"OEvŽZ‚Å‚ ‚é.ƒA ƒCƒ\ ƒNƒ• ƒ"-@‚É ‚ae ‚é "¯ ˆÊ 'Ì "N'ã ‚AE"¯ ˆÊ 'Ì "ä •‰• ¶ 'l(ˆÈ ‰º,•‰ • ¶ 'l ‚AE-ª) ‚Í 'n ‹…‰È Šw‚Ì •ª-ì ‚É‚¨‚¢‚É‚¨‚¢ ‚Ä"ñ •í ‚É•d-v‚È•î •ñ("c ' † ,1984; Žü"¡,1985;‰Á •X"ü ‚Ù‚©,1993)‚ð-^‚¦ ‚Ä ‚-‚ê ‚é ‚ª,‚» ‚Ì ŽZ•o •û-@(McIntyre et al.,1966;York,1966;York, 1969;Brooks et al.,1968;Brooks et al.,1972;John et al.,1990)‚Í "• ˆê ‚³ ‚ê ‚Ä‚¨‚ç‚Ä‚¨‚ç ‚¸OE¤‹‚¸OE¤‹ † ŽÒ‚É ‚ae ‚Á‚Ä-l•X‚È OEv ŽZ•û-@‚ð•Ì-p‚µ ‚Ä‚¢ ‚é.‚» ‚Ì OE‹‰Ê,•ñ •• ‚³ ‚ê ‚é "¯ ˆÊ 'Ì "N'ã ‚â •‰• ¶ 'l ‚É‹Í ‚©‚Å‚Í ‚ ‚é ‚ª •· ˆÙ‚ª "F ‚ß ‚ç ‚ê ‚é(Brooks et al.,1972).-á ‚¦ ‚ÎˆÙ‚È‚ÎˆÙ‚È ‚é ‰Î•¬ Šâ 'Ì ‚Ì ‚¨‚¨‚Ü‚©‚¨‚¨‚¨‚¨‚Ü‚© ‚È "ä Šr(-k •ã 'Ñ ‚AEˆ¢ •• OEG 'Ñ ‚Ì ‰Ô ›¼Šâ-Þ 'S 'Ì ‚Ì "N'ã "ä Šr)‚Å ‚Í ‚± ‚Ì •· ˆÙ ‚Í-â'è ‚AE‚È ‚ç ‚È ‚¢ ‚© ‚à ‚µ ‚ê ‚È ‚¢ ‚ª,OEµ-§ ‚È ‹c˜_‹c˜_ ‚ð•s ‚¤•ê • ‡ (-k •ã 'Ñ' † ‚Å‚Ì Še ‰Ô ›¼Šâ 'Ì ‚Ì OE`•¬ "N'ã ‚Ì "ä Šr)‚Í •s "s • ‡ ‚ª • ¶ ‚ ¶ ‚é ‚Å‚ ‚ë ‚¤.‚± ‚Ì ‚ae ‚¤ ‚È•· ˆÙ ‚ð ‚È ‚-‚· ‚½‚ß ‚É ‚Í OE¤‹ † ŽÒ ‚ª "• ˆê.‚µ ‚½"¯ ˆÊ 'Ì ƒf •[ ƒ^ ‚Ì Žae‚舵 ‚¢ ‚AE OEvŽZ•ˆ-•‚ð •s ‚¤•K-v ‚ª ‚ ‚é.-{ ˜_ ‚Å‚Í OEvŽZ•ˆ-•‚Ì "• ˆê‰»‚ð '£ ‚· ‚½‚ß ‚ÉOE»•Ý"ä Šr "I '½ ‚-‚Ì OE¤‹ † ŽÒ‚ª-˜-p‚µ ‚Ä‚¢ ‚é ƒAƒCƒ\ ƒNƒ• ƒ"ŽZ•o •û-@‚ð •à-¾ ‚µ,‚» ‚Ì OEvŽZƒv ƒ• ƒOƒ‰ ƒ€ ‚ð •Ð‰î‚· ‚é. ‚È‚¨,-{ ˜_ ‚ÅŽae‚è•ã ‚° ‚é ƒAƒCƒ\ ƒNƒ• ƒ"OEvŽZ•û-@‚ÍYork (1966)‚É ‚ae‚é ‚à ‚Ì ‚Å‚ ‚è,•¸ "x ‚ð ‹c˜_‹c˜_ ‚· ‚é ‚½‚ß ‚Ì Žw•W‚AE ‚µ‚ÄMSWD(mean square weighted deviation:McIntyre et al.,1966)‚ð •Ì-p‚µ ‚½. 2.York(1966)‚Ì OEvŽZ•û-@‚Ì ŠT-v ƒAƒCƒ\ ƒNƒ• ƒ"OEvŽZ•û-@‚Í Šî-{ "I ‚É ‚Í •Å•¬ "ñ•ae-@‚Å‚ ‚é. ‚½‚¾ ‚µ,OE •X‚Ì ƒ| ƒCƒ" ƒg‚ÉOEë•· ‚ª ŠÜ‚Ü‚ê ‚Ä‚¨‚è‚Ä‚¨‚è,‚» ‚Ì OEë•· ‚Ì Žae‚舵 ‚¢ •û ‚ª OE¤‹ † ŽÒ‚É ‚ae‚Á‚Ĉ٠‚È ‚Á‚Ä‚¢ ‚é.York(1966) ‚Í87Sr/86Sr‚AE87Rb/86Sr‚Ì ‚Ç‚¿ ‚ç ‚É ‚àOEë•· ‚ª ‚È ‚¢ •ê • ‡,‚Ç ‚¿ ‚ç‚©ˆê •û ‚ÉOEë•· ‚ª ŠÜ‚Ü‚ê ‚é •ê • ‡,-¼ •û ‚ÉOEë•· ‚ª ŠÜ‚Ü‚ê ‚é •ê • ‡ ‚ɂ‚¢ ‚Ä‚» ‚ê ‚¼‚ê˜_‚¼‚ê˜_ ‚ ¶ ‚½.'Ê •í ‰ä•X‚ªˆµX‚ªˆµ ‚¤ ƒf •[ ƒ^(ƒA ƒC ƒ\ ƒNƒ• ƒ"•} •ã ‚Ì1‚ ‚Ì "_)‚É ‚Í OEë•· ‚ª ŠÜ‚Ü‚ê ‚Ä ‚¢ ‚é ‚Ì ‚Å 87Sr/86Sr‚AE87Rb/86Sr‚Ì-¼ •û ‚ÉOEë•· ‚ª ‚ ‚é •ê • ‡ ‚ð Žae‚è•ã ‚° ‚é. ‚± ‚Ì87Sr/86Sr‚AE87Rb/86Sr‚É •t •• ‚· ‚é OEë•· ‚Í 'Ê •íRelative Deviate(ˆÈ ‰ºRel.Dev.‚AE-ª)‚AE OEÄ ‚Î ‚ê,•W •€ ŽŽ-¿‚È ‚Ç 'P ˆê ‚Ì ŽŽ-¿‚ɂ‚¢ ‚Ä•¡ •" ‰ñ 'ª 'è ‚µ ‚½•W•€ •Î •·(1ƒÐ)‚É 'Î ‚· ‚é ŠÖ•" ‚AE‚µ ‚Ä-^ ‚¦ ‚ç ‚ê ‚é.‚· ‚È ‚í ‚¿ ŽŸŽ®‚É ‚ae‚Á‚Ä‹• ‚ß ‚ç ‚ê ‚é.