TY - JOUR
T1 - The global accretion rate of extraterrestrial materials in the last glacial period estimated from the abundance of micrometeorites in Antarctic glacier ice
AU - Yada, Toru
AU - Nakamura, Tomoki
AU - Takaoka, Nobuo
AU - Noguchi, Takaaki
AU - Terada, Kentaro
AU - Yano, Hajime
AU - Nakazawa, Takakiyo
AU - Kojima, Hideyasu
N1 - Funding Information:
Acknowledgments. This study is indebted to the members of JARE-39 for collecting the AMMs samples; and is supported by the Japanese AMM research team, I. Nakai, K. Nagao, H. Hiyagon, N. Imae, T. Fukuoka, K. Nogami, H. Ohashi, T. Murakami, R. Ohmori, W. Nozaki, T. Osawa, S. Mizutani, N. Matsumoto, J. Ka-mata, T. Mori, M. Sasaki, M. Itabashi and T. Setoyanagi. We are very grateful to Prof. Yoshiyuki Fujii in NIPR, for much valuable advice about glaciology. We express special thanks to Dr. Minoru Sekiya in Kyushu Univ. for discussions about this study, and Dr. Susan Taylor in U.S. Army Cold Regions Research and Engineering Laboratory for helpful comments. We are grateful to Dr. Christine Floss of Washington University in St. Louis for help with the English. Thoughtful reviews by Dr. Michael E. Zolensky and an anonymous reviewer are greatly appreciated, and led to considerable improvements of this paper. We thank the Antarctic Meteorite Research Center of NIPR for use of analytical machines and facilities. This study is partially supported by the Research Fellowships of the Japan Society for the Promotion of Science for Young Scientists, given to T.Y., by the research fund of NIPR, by the cooperative program of the Institute for Cosmic Ray Research, University of Tokyo, and by the Scientific Research Grant-in-Aid of the Ministry of Education, Culture, Sports, Science and Technology (No. 11440163 to H.K. and No. 13740318 to T.N.).
PY - 2004
Y1 - 2004
N2 - The accretion rate of micrometeorites in the last glacial period was estimated from the concentrations of micrometeorites in the blue ice around the Yamato Mts. in Antarctica. The samples from this study were collected from the five sampling points (M03, K02, K11, J09 and J10) in the blue ice. The blue ice was melted and filtered, and the micrometeorites were handpicked from the collected "glacial sands". The weight of the micrometeorites in the blue ice was estimated from the abundance of recovered micrometeorites and the solar noble gas concentrations in the "residue" after handpicking. The age of the blue ice from the K area was estimated to be 27-33 kyr before present based on oxygen isotope data. The estimated accretion rate to the whole Earth ranges from 5300 × 103kg/a to 16000 × 103kg/a. However, the lower end of this range probably represents lower limits due to possible loss of solar noble gases during long residence in the glacier ice. Hence, we estimate that the accretion rate of micrometeorites 27-33 kyr before present to be in the range between (11000 ± 6600) × 103kg/a and (16000 ± 9100) × 103kg/a. These results, as well as the other estimates, suggest that the accretion rate of micrometeorites in the last glacial period was comparable to that in the present.
AB - The accretion rate of micrometeorites in the last glacial period was estimated from the concentrations of micrometeorites in the blue ice around the Yamato Mts. in Antarctica. The samples from this study were collected from the five sampling points (M03, K02, K11, J09 and J10) in the blue ice. The blue ice was melted and filtered, and the micrometeorites were handpicked from the collected "glacial sands". The weight of the micrometeorites in the blue ice was estimated from the abundance of recovered micrometeorites and the solar noble gas concentrations in the "residue" after handpicking. The age of the blue ice from the K area was estimated to be 27-33 kyr before present based on oxygen isotope data. The estimated accretion rate to the whole Earth ranges from 5300 × 103kg/a to 16000 × 103kg/a. However, the lower end of this range probably represents lower limits due to possible loss of solar noble gases during long residence in the glacier ice. Hence, we estimate that the accretion rate of micrometeorites 27-33 kyr before present to be in the range between (11000 ± 6600) × 103kg/a and (16000 ± 9100) × 103kg/a. These results, as well as the other estimates, suggest that the accretion rate of micrometeorites in the last glacial period was comparable to that in the present.
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U2 - 10.1186/BF03352491
DO - 10.1186/BF03352491
M3 - Article
AN - SCOPUS:20644437112
SN - 1343-8832
VL - 56
SP - 67
EP - 79
JO - Earth, Planets and Space
JF - Earth, Planets and Space
IS - 1
ER -