An accurate determination of water content in garnet is critical to quantify the transport of water to the deep mantle by the subducted oceanic crust beyond the breakdown of hydrous phases. Fourier transform infrared spectroscopy (FTIR) is the most widely used approach to determine the species and contents of water in garnet. Accurate quantification of OH in garnet requires independent calibration using an external method, as OH absorbance is mineral and composition specific. To obtain the infrared absorption coefficients of structural hydroxyl in garnet, a combined study of spectrometric analyses by FTIR and a method combining a thermal conversion elemental analyser with isotope ratio mass spectrometry (TC/EA-MS) was carried out for fourteen gem-quality natural garnet crystals with variable compositions. The obtained molar absorption coefficients were 9322 ± 338 and 240 ± 26 l mol−1 cm−2 for grossular- and spessartine-rich garnet and pyrope-almandine garnet, respectively. These results are within the range of previous studies. A new molar absorption coefficient of 689 ± 177 l mol−1 cm−2 was obtained for pyrope-spessartine garnet. The large variation in the absorption coefficient indicates it is controlled by both garnet composition and OH-absorption bands. The obtained absorption coefficients are only appropriate for certain types of eclogitic garnet, and more studies should be carried out on eclogitic garnets. 相似文献
The degree and scale of underground space development are growing with the continuous advancement of urbanization in China. The lack of research on the change of the groundwater flow field before and after the development of underground space has led to various problems in the process of underground space development and operation. This paper took the key development zone of the Xiong’an New Area as the study area, and used the Groundwater modeling system software (GMS) to analyse the influence on the groundwater flow field under the point, line, and surface development modes. The main results showed that the underground space development would lead to the expansion and deepening of the cone of depression in the aquifer. The groundwater level on the upstream face of the underground structure would rise, while the water level on the downstream face would drop. The “line” concurrent development has the least impact on the groundwater flow field, and the maximum rise of water level on the upstream side of the underground structure is expected to be approximately 3.05 m. The “surface” development has the greatest impact on the groundwater flow field, and the maximum rise of water level is expected to be 7.17 m. 相似文献
Surveys in Geophysics - Until now, the prismatic mass approximation of the topography and the constant density assumption have been mostly utilized in topographic reductions, which are rough... 相似文献
Mega-earthquakes and extreme climate events accompanied by intrinsic fragile geology lead to numerous landslides along mountain highways in Taiwan, causing enormous life and economic losses. In this study, a system for rapid slope disaster information integration and assessment is proposed with the aim of providing information on landslide occurrence, failure mechanisms, and subsequent landslide-affected areas to the highway authority rapidly. The functionality of the proposed system is deployed into three units: (1) geohazard rapid report (GeoPORT I), (2) multidisciplinary geological survey report (GeoPORT II), and (3) site-specific landslide simulation report (GeoPORT III). After landslide occurrence, the seismology-based monitoring network rapidly provides the initial slope disaster information, including preliminary location, event magnitude, earthquake activity, and source dynamics, within an hour. Within 3 days of the landslide, a multidisciplinary geological survey is conducted to collect high-precision topographical, geological, and remote-sensing data to determine the possible failure mechanism. After integrating the aforementioned information, a full-scale three-dimensional landslide simulation based on the discrete element method is performed within 10 days to reveal the failure process and to identify the areas potentially affected by subsequent disasters through scenario modeling. Overall, the proposed system can promptly provide comprehensive and objective information to relevant authorities after the event occurrence for hazard assessment. The proposed system was validated using a landslide event in the Central Cross-Island Highway of Taiwan.