Water contents of Roberts Victor xenolithic eclogites: primary and metasomatic controls     

Jin-Xiang?HuangEmail author  Pei?Li  William?L.?Griffin  Qun-Ke?Xia  Yoann?Gréau  Norman?J.?Pearson  Suzanne?Y.?O’Reilly 《Contributions to Mineralogy and Petrology》2014,168(6):1092

A suite of eclogites from the Roberts Victor kimberlite has been extensively characterized in terms of petrology and geochemical compositions (Gréau et al. in Geochim Cosmochim Acta 75(22):6927–6954, 2011; Huang et al. in Lithos 142–143:161–181, 2012a). In the present study, the water contents of eclogitic garnet and omphacite were analyzed by Fourier transform infrared spectrometry. Garnet does not contain measureable OH in any sample. The water content of omphacite in the studied eclogites ranges from 211 to 1,496 ppm. Mantle metasomatism has modified the water content of some of the eclogites, while others retain water contents characteristic of their original environment. The OH contents of the metasomatized eclogites may be mainly controlled by the H₂O fugacity and mineral compositions. The OH contents of the non-metasomatized samples are interpreted to be more sensitive to their mantle equilibration temperature, pressure, and the local fugacities of H₂O and O₂. The calculated water content of the metasomatic medium is similar to that of carbonatitic–kimberlitic melts/fluids. Eclogites contain more water than peridotites recorded in the literature (341 ± 161 vs 122 ± 54 ppm) and represent an important water reservoir in the lithospheric mantle wherever they occur. This is an important parameter to be considered in the interpretation of mantle processes and geophysical data such as seismic wave speeds and electrical conductivity, and in geodynamic modeling.  相似文献   

A three-dimensional analytical tool for modeling reactive transport     

Jones NL  Clement TP  Hansen CM 《Ground water》2006,44(4):613-617

In this note, we present a public domain analytical reactive transport modeling tool (ART3D, version 2.0). The tool is developed in FORTRAN and can be used for solving a system of a set of partial differential equations coupled with a first-order reaction network. ART3D uses a novel analytic solution technique proposed by Clement. The new software includes options for performing Monte Carlo simulations and automated parameter estimation.  相似文献   

Morphometric comparisons between automated and manual karst depression inventories in Apalachicola National Forest,Florida, and Mammoth Cave National Park,Kentucky, USA   总被引：1，自引：0，他引：1  

John Wall  DelWayne R. Bohnenstiehl  Karl W. Wegmann  Norman S. Levine 《Natural Hazards》2017,85(2):729-749

Karst depression catalogs are critical to assessing the hydrology and geohazards of an area; yet, the delineation of these features within a landscape can be a difficult, time-consuming and subjective task. This study evaluates the efficacy of karst depression inventorying using an automated fill-difference method operating on high-resolution lidar-derived digital elevation models (DEMs). The resulting catalog is compared with existing karst depression inventories for two low-development areas of the USA, Mammoth Cave National Park (MACA) and Apalachicola National Forest (ANF), where karst depressions have been mapped previously using a manual closed-contour approach. The automated fill method captures 93 and 85 % of these previously mapped karst depressions at MACA and ANF, respectively. Field observations and topographic analysis suggest that the omitted features were likely misclassified within the existing catalogs. The automated routine returns 797 and 3377 additional topographic depressions, at MACA and ANF, respectively, which are not included in the existing catalogs. While the geology of ANF is mostly homogenous Quaternary deposits, the newly identified, typically smaller-scale depressions found within MACA tend to be disproportionally located in non-carbonate-dominated formations, where the development of karst may be restricted by geologic heterogeneity. Within both areas, the size distributions of the two inventories are statistically identical for features larger than ~10³ m² in area or ~3 m in depth. For individual depressions captured by both methods at MACA, the automated fill-difference routine tends to return a slightly larger estimate of depression size and aggregate small depressions into larger ones. Conversely, at ANF, some low-relief depressions may be disaggregated by the fill-difference technique, with a trend toward smaller estimated depression areas when the automated method is employed. The automated fill-difference method, operating on high-resolution lidar-derived DEMs, can reproduce and expand the existing inventories of karst depressions, while minimizing false detections that may be inherent within pre-existing catalogs.  相似文献   

Archaeological obsidian studies: Method and theory     

Norman Herz 《Geoarchaeology》1999,14(6):591-594

  相似文献