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This ethnoarchaeological study at the Q'eqchi' Maya village of Las Pozas, Guatemala, aimed to refine the understanding of the relationship between soil chemical signatures and human activities for archaeological applications. The research involved phosphorus, exchangeable ion (calcium, potassium, magnesium, sodium), and trace element analysis of soils and earth floors extracted by Mehlich II, ammonium acetate, and DTPA chelate solutions, respectively. The results showed high levels of phosphorus, potassium, magnesium, and pH in food preparation areas, as well as high phosphorus concentrations and low pH in food consumption areas. The traffic areas exhibited low phosphorus and trace element contents, whereas refuse disposal areas were enriched. These results provide important information for the understanding of space use in ancient settlements. © 2002 Wiley Periodicals, Inc. 相似文献
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Sohiko Kameyama Satoshi Yoshida Hiroshi Tanimoto Satoshi Inomata Koji Suzuki Hisayuki Yoshikawa-Inoue 《Journal of Oceanography》2014,70(3):225-239
We measured dissolved isoprene (2-methyl-1,3-butadiene; C5H8) concentrations in a broad area of the southern Indian Ocean and in the Indian sector of the Southern Ocean from 35°S to 64°S and from 37°E to 111°E during austral summer 2010–2011. Isoprene concentrations were continuously measured by use of a proton-transfer-reaction mass spectrometer combined with a bubbling-type equilibrator. Concentrations of isoprene and its emission flux throughout the study period ranged from 0.2 to 395 pmol L?1 and from 181 to 313 nmol m?2 day?1, respectively, the averages being generally higher than those of previous studies. Although we found a significant linear positive relationship between isoprene and chlorophyll-a concentrations (r 2 = 0.37, n = 36, P < 0.001), the correlation coefficient was lower than previously reported. In contrast, in the high-latitude area (>53°S) we identified a significant negative correlation (r 2 = 0.59, n = 1263, P < 0.001) between isoprene and the temperature-normalized partial pressure of carbon dioxide (n-pCO2), used as an indicator of net community production in this study. This suggests that residence times and factors controlling variations in isoprene and n-pCO2 are similar within a physically stable water column. 相似文献
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We analyzed noble gases in nine individual chondrules, an assemblage of small chondrules, and four whole‐rock samples of the Allende CV3 chondrite. Major elements were also determined for five chondrules. The cosmic ray exposure ages are calculated from cosmogenic 3He to be 5.17 ± 0.38 and 5.15 ± 0.25 Myr for the averages of the chondrules and whole rocks, respectively, showing no significant pre‐exposure evidence for the studied chondrules. Large amounts of 36Ar, 80,82Kr, and 128Xe produced by neutron capture are observed in most samples; the abundances of these nuclides are correlated among the samples. The epithermal neutron flux and neutron slowing down density are calculated based on [80Kr]n, from which a sample depth of about 30 cm can be calculated. The measured chondrules contain variable amounts of radiogenic 129Xe. The abundance ratios of radiogenic 129Xe to neutron capture–produced 128Xe are rather constant among the studied chondrules; four chondrules give more precise ratios at the high‐temperature fractions, ranging from 1920 ± 80 to 2280 ± 140, which corresponds to a time difference of 3.9 ± 2.4 Myr. It is noticeable that most chondrules also contain 244Pu‐derived fission Xe. The average 244Pu/238U ratio for nine chondrules is 0.0069 ± 0.0018, which agrees well with the preferred ratio reported for chondrites. 相似文献
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Ryota Fukai Tomohiro Usui Wataru Fujiya Yoshinori Takano Ken-ichi Bajo Andrew Beck Enrica Bonato Nancy L. Chabot Yoshihiro Furukawa Hidenori Genda Yuki Hibiya Fred Jourdan Thorsten Kleine Mizuho Koike Moe Matsuoka Yayoi N. Miura Frédéric Moynier Ryuji Okazaki Sara S. Russell Hirochika Sumino Michael E. Zolensky Haruna Sugahara Shogo Tachibana Kanako Sakamoto Masanao Abe Yuichiro Cho Kiyoshi Kuramoto 《Meteoritics & planetary science》2024,59(2):321-337
Japan Aerospace Exploration Agency's Martian Moons eXploration (MMX) mission will launch a spacecraft in 2024 to return samples from Phobos in 2029. Curatorial work for the returned Phobos samples is critical for the sample allocation without degrading the sample integrity and subsequent sample analysis that will provide new constraints on the origin of Phobos and the evolution of the circum-Mars environment. The Sample Analysis Working Team of the MMX is designing the sample curation protocol. The curation protocol consists of three phases: (1) quick analysis (extraction and mass spectrometry for gases), (2) pre-basic characterization (bulk-scale observation), and (3) basic characterization (grain-by-grain observation and allocation of the sample aliquots). Nondestructive analyses within the clean chamber (e.g., visible and near-infrared spectral imaging) and outside the chamber (e.g., gas mass spectrometry) are incorporated into the curation flow in coordination with the MMX mission instrument teams for ground-truthing the remote-sensing data sets. The MMX curation/sample analysis flow enables the seamless integration between the sample and remote-sensing data sets to maximize the scientific value of the collected Phobos samples. 相似文献
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Yayoi Fujita Lagerqvist Laura Woollacott Avakat Phasouysaingam Southida Souliyavong 《The Australian geographer》2014,45(3):407-417
ABSTRACTGovernment efforts to industrialise and modernise the Lao economy through intensive resource development are having adverse effects on rural livelihoods as resources are degraded and access to limited land and natural resources has intensified. In one of the country's key river basins, Nam Ngum, a series of resource developments including hydropower, mining and agricultural plantations have modified the landscape over the last four decades. Uncoordinated resource developments are putting intense pressure on increasingly scarce natural resources and affecting the lives of people who are dependent on them. Economic diversification of rural households in Feuang District in the Nam Ngum River Basin has created significant discrepancies between the rich and the poor, yet all households remain primarily dependent on agriculture. Land is of enduring importance to rural livelihoods. National development intervention has failed to secure basic livelihoods for rural households. 相似文献
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