Atmospheric CO₂ concentrations and δ¹³C values across the Antarctic Circumpolar Current between New Zealand and Antarctica     

ANTONIO LONGINELLI  FEDERICO GIGLIO  LEONARDO LANGONE  RENZO LENAZ  CARLO ORI  ENRICOMARIA SELMO 《Tellus. Series B, Chemical and physical meteorology》2007,59(1):130-137

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δ18O and chemical composition of Libyan Desert Glass,country rocks,and sands: New considerations on target material     

Antonio LONGINELLI  Giampaolo SIGHINOLFI  Vincenzo De MICHELE  Enricomaria SELMO 《Meteoritics & planetary science》2011,46(2):218-227

Oxygen isotope and chemical measurements were carried out on 25 samples of Libyan Desert Glass (LDG), 21 samples of sandstone, and 3 of sand from the same area. The δ¹⁸O of LDG samples range from 9.0‰ to 11.9‰ (Vienna Standard Mean Ocean Water [VSMOW]); some correlations between isotope data and typological features of the LDG samples are pointed out. The initial δ¹⁸O of a bulk parent material may be slightly increased by fusion due to the loss of isotopically light pore water with no isotope exchange with oxygen containing minerals. Accordingly, the δ¹⁸O of the bulk parent material of LDG may have been about 9.0 ± 1‰ (VSMOW). The measured bulk sandstone and sand samples have δ¹⁸O values ranging from 12.6‰ to 19.5‰ and are consequently ruled out as parent materials, matching the results of previous studies. However, separated quartz fractions have δ¹⁸O values compatible with the LDG values suggesting that the modern surface sand inherited quartz from the target material. This hypothesis fits previous findings of lechatelierite and baddeleyite in these materials. As the age of the parent material reported in previous studies is Pan‐African, we measured the δ¹⁸O values of bulk rock and quartz from intrusives of Pan‐African age and the results obtained were compatible with the LDG values. The main element abundances (Fe, Mg, Ca, K, Na) in our LDG samples conform to previous estimates; Fe, Mg, and K tend to be higher in heterogeneous samples with dark layers. The hypothesis of a low‐altitude airburst involving silica‐rich surface materials deriving from weathered intrusives of Pan‐African age, partially melted and blown over a huge surface by supersonic winds matches the results obtained.  相似文献   

Concentrations and  δ¹³C  values of atmospheric CO₂ from oceanic atmosphere through time: polluted and non-polluted areas     

ANTONIO LONGINELLI  RENZO LENAZ  CARLO ORI  ENRICO SELMO 《Tellus. Series B, Chemical and physical meteorology》2005,57(5):385-390

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