Geomorphic influences on the distribution and accumulation of pyrogenic carbon (PyC) following a low severity wildfire in northern New Mexico          下载免费PDF全文

Amy Galanter  Daniel Cadol  Kathleen Lohse 《地球表面变化过程与地形》2018,43(10):2207-2218

The distribution, transport, and accumulation of wildfire‐generated pyrogenic carbon (PyC) has important consequences for contaminant transport and carbon cycling, but a conceptual model for PyC accumulation and loss that includes geomorphic processes is lacking. In this study we quantified PyC concentration in soil samples collected from the Jemez Mountains of New Mexico before and after the 2013 Thompson Ridge (TR) fire, and developed a conceptual model describing PyC redistribution. Pre‐fire samples were fortuitously collected 4 years before the TR burn and post‐fire samples were collected at the same locations 15 months following the TR fire. Samples were collected from the O and A horizon, with sites representing a range of slope angle, aspect, burn severity, and geomorphic setting. PyC was determined by a modified chemo‐thermal oxidation method to compare PyC to total organic carbon (TOC). The mean PyC/TOC ratio was significantly higher post‐fire than pre‐fire (0.14 vs 0.12), indicating increased PyC sequestration. O horizon PyC concentrations were more variable and more responsive to fire than the A horizon. Soil horizon, watershed, and geomorphic setting proved to be the most influential factors in predicting PyC concentration changes. PyC concentrations increased most on hillslopes and in low‐severity burn areas, suggesting higher rates of PyC production or post‐fire accumulation. Burn patchiness appears to facilitate PyC accumulation, with lower severity patches trapping PyC mobilized from high severity patches. While PyC content had greater point scale variance following the fire, the fire also homogenized pre‐fire PyC differences between soil horizons and among watersheds within the burn perimeter, differences that appear to develop over time between fires. The O horizon is a larger sink for PyC in the short term following fire, but based on pre‐fire concentrations the A horizon appears to be a more stable sink for PyC. Copyright © 2018 John Wiley & Sons, Ltd.  相似文献   

Florisbad—New investigations at a middle stone age Hominid Site in South Africa     

Kathleen Kuman  R. J. Clarke 《Geoarchaeology》1986,1(2):103-125

First results of renewed excavations at the Middle Stone Age spring site of Florisbad are reported. Seven meters of deposits dating possibly from the later mid-Pleistocene to the mid-Holocene contain several cultural phases and record alternating periods of increased spring flow versus more stabilized conditions. The archaic Homo sapiens cranium discovered in 1932 and the Florisian Land Mammal Age fauna retrieved from the springs are argued to derive from the earliest deposits, estimated to be ca. 100,000–200,000 years old. In an Upper Pleistocene layer beyond the range of Carbon-14 dating, a Middle Stone Age occupation floor has been excavated. This we interpret as a multiple-occupation kill, butchery, or scavenging site. The presence of a hearth, of chipping debris under 10 mm in size, and the limited displacement of artifacts which have been refitted as conjoining pieces demonstrate a minimally disturbed, primary context site.  相似文献   

The archaeology of geological catastrophes     

Kathleen Nicoll 《Geoarchaeology》2003,18(3):403-405

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Eco-districts in France: What tools to ensure goals achievement?     

Boquet  Kathleen  Froitier  Charline  Li  Jinhui  Xu  Kaihua  Zeng  Xianlai 《中国科学:地球科学(英文版)》2020,63(6):865-874

Globally, to build cities and communities more inclusive, safe, resilient and sustainable is one of the most important sustainable development goals. Eco-districts in cities emerged as an answer to current global environmental concerns and have been developed in France since the 1990s. The objective of this work is to gather operational feedback from sustainable neighborhood projects owners to better understand the key barriers of such projects and how to overcome them. A case study of the eco-district Les Tanneries, Lingolsheim showed that the carbon footprint of each inhabitant annually amounted to 4 tons CO_2 equivalent, more than half of the French average. Rooms for improvements were clearly identified regarding transports and food carbon footprint. Indicators for energy consumption, social diversity and density reached the level of the eco-districts average. A governance review pointed out some superior practices such as the formalization of a specification requirements handbook, a competition between project management teams, and the use of neighborhood sustainability assessment tools to measure and track changes in performance. The validated tools and obtained results can be useful in building sustainable cities and even China's ecological civilization.  相似文献   

Coral reef fishing and coral-algal phase shifts: implications for global reef status   总被引：8，自引：0，他引：8  

McManus  John W.; Menez  Lambert A. B.; Kesner-Reyes  Kathleen N.; Vergara  Sheila G.; Ablan  M. C. 《ICES Journal of Marine Science》2000,57(3):572-578

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Archaeological site distribution by geomorphic setting in the southern lower Cuyahoga River Valley,northeastern Ohio: Initial observations from a GIS database     

Andrew Bauer  Kathleen Nicoll  Lisa Park  Timothy Matney 《Geoarchaeology》2004,19(8):711-729

In this study, we compiled unpublished archival documentation of archaeological site locations from the southern part of the Cuyahoga River Valley in northeastern Ohio, USA, registered at the State of Ohio Historic Preservation Office into a Geographic Information Systems (GIS) database. Using digitized soil shapefiles to generate a geomorphic data layer, we assessed the spatial and temporal distribution of 79 known archaeological sites by landform association. This digital compilation indicates that Woodland period, Late Prehistoric, and Historic sites occur in most geomorphic settings along the river valley. In contrast, Paleoindian and Archaic sites only occur on Wisconsinan cut terraces and in upland interfluve settings, indicating that most of these documented sites are in primary contexts and have not been reworked. We discuss the distribution of archaeological sites in the study region as a function of various factors, including cultural activities, taphonomic processes, landform development, and the nature and extent of the original archaeological surveys. Observed spatial patterns of known sites clearly reflect local geomorphological controls; artifactual contexts from the earlier prehistoric periods are underrepresented in the database. We conclude that additional site surveys, as well as the excavation and documentation of new sites in this part of Ohio, are required to understand local prehistoric economies and to ascertain patterns of culturally mediated land use. © 2004 Wiley Periodicals, Inc.  相似文献   

Genesis of marine terrace soils,Barbados, West Indies: Evidence from mineralogy and geochemistry     

Daniel R. Muhs  Russell C. Crittenden  John N. Rosholt  Charles A. Bush  Kathleen C. Stewart 《地球表面变化过程与地形》1987,12(6):605-618

Well-developed, clay-rich soils dominated by interstratified kaolinite-smectite are found on the uplifted coral reef terraces on the island of Barbados. The reef limestone is unlikely to have been the soil parent material however, because it is 98 per cent CaCO₃ and geomorphic evidence argues against the 20 m of reef solution required to produce the soils by this process. The mineralogy of the sand, silt, and clay fractions of the soils, and trace element geochemistry, suggest that aeolian materials carried on the trade winds from Africa, volcanic ash from the island of St. Vincent, and quartz from Tertiary bedrock on the island itself are the parent materials for the soils.  相似文献   

Variation in pyrite size, form, and microlithotype association in the springfield (no. 9) and herrin (no. 11) coals, Western Kentucky     

Kathleen Adams Frankie  James C. Hower 《International Journal of Coal Geology》1987,7(4)

Channel samples of the Springfield (No. 9) and Herrin (No. 11) (Pennsylvanian, Desmoinesian/Westphalian D) coals were acquired in three mines each in the Western Kentucky coal field. Pyrite was characterized petrographically in terms of its size, form, and microlithotype association. Within each coal seam significant variations in the amount of pyrite of certain forms occurred between the sites. Pyritic sulfur as determined chemically did not exhibit significant variation between the seams or between the sites. The variation in dendritic pyrite in vitrite plus clarite between seams and between sites was highly significant and the variation in framboidal pyrite in vitrite plus clarite between sites was also highly significant.  相似文献   

Cyclic and event stratification: G. Einsele and A. Seilacher (Editors). Springer,Berlin, 1982, xiv + 540 pp., DM 60.00/approx. US $ 28.00 (paperback)     

Edwin D. McKee 《Sedimentary Geology》1983,35(3):228-230

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Detection of an Impermeable Boundary in an Anisotropic Formation: A Case Study     

S. C. Way  C. R. McKee 《Ground water》1984,22(5):579-583

Direct mirror-well image theory to locate an impermeable boundary does not apply in anisotropic formations because the relationship between flow lines and equipotential lines is distorted due to directional transmissivity. A simple approach enables an impermeable boundary to be located in anisotropic formations, and it can be verified with a field example.  相似文献