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11.
Giada Iacono Marziano Fabrice Gaillard Michel Pichavant 《Contributions to Mineralogy and Petrology》2008,155(6):719-738
The results of an experimental study of limestone assimilation by hydrated basaltic magmas in the range 1,050–1,150°C, 0.1–500 MPa
are reported. Alkali basalts doped with up to 19 wt% of Ca, Mg-carbonates were equilibrated in internally heated pressure
vessels and the resulting phase relationships are described. The major effects of carbonate incorporation are: (1) generation
of CO2-rich fluid phases; (2) change in liquidus phase equilibria; the crystallization of Ca-rich clinopyroxene is favored and the
other phases (e.g. olivine, plagioclase), present in the absence of carbonate assimilation, are consumed. As a consequence
of the massive clinopyroxene crystallization, the residual melt is strongly silica-depleted and becomes nepheline-normative.
Compositional and mineralogical evolutions observed in Mt. Vesuvius eruptive products match those documented in our experiments
with added carbonates, suggesting the possibility that carbonate assimilation increased during the last 25 ka of activity.
In Central-Southern Italy, carbonate assimilation at shallow levels probably superimposes on deeper source heterogeneities. 相似文献
12.
Seismic Modal Contribution Factors 总被引：1，自引：0，他引：1
Michele Palermo Stefano Silvestri Giada Gasparini Tomaso Trombetti 《Bulletin of Earthquake Engineering》2015,13(10):2867-2891
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Giada Iacono Marziano Fabrice Gaillard Michel Pichavant 《Journal of Volcanology and Geothermal Research》2007
The Alban Hills volcanic region (20 km south of Rome, in the Roman Province) emitted a large volume of potassic magmas (> 280 km3) during the Quaternary. Chemical interactions between ascending magmas and the ∼ 7000–8000-m-thick sedimentary carbonate basement are documented by abundant high temperature skarn xenoliths in the eruptive products and have been frequently corroborated by geochemical surveys. In this paper we characterize the effect of carbonate assimilation on phase relationships at 200 MPa and 1150–1050 °C by experimental petrology. Calcite and dolomite addition promotes the crystallization of Ca-rich pyroxene and Mg-rich olivine respectively, and addition of both carbonates results in the desilication of the melt. Furthermore, carbonate assimilation liberates a large quantity of CO2-rich fluid. A comparison of experimental versus natural mineral, glass and bulk rock compositions suggests large variations in the degree of carbonate assimilation for the different Alban Hills eruptions. A maximum of 15 wt.% assimilation is suggested by some melt inclusion and clinopyroxene compositions; however, most of the natural data indicate assimilation of between 3 and 12 wt.% carbonate. Current high CO2 emissions in this area most likely indicate that such an assimilation process still occurs at depth. We calculate that a magma intruding into the carbonate basement with a rate of ∼ 1 – 2 · 106 m3/year, estimated by geophysical studies, and assimilating 3–12 wt.% of host rocks would release an amount of CO2 matching the current yearly emissions at the Alban Hills. Our results strongly suggest that current CO2 emissions in this region are the shallow manifestation of hot mafic magma intrusion in the carbonate-hosted reservoir at 5–6 km depth, with important consequences for the present-day volcanic hazard evaluation in this densely populated and historical area. 相似文献
15.
Marianna?Siino Giada?AdelfioEmail authorView author&#;s OrcID profile Jorge?Mateu 《Stochastic Environmental Research and Risk Assessment (SERRA)》2018,32(12):3525-3539
We propose a new fitting method to estimate the set of second-order parameters for the class of homogeneous spatio-temporal log-Gaussian Cox point processes. With simulations, we show that the proposed minimum contrast procedure, based on the spatio-temporal pair correlation function, provides reliable estimates and we compare the results with the current available methods. Moreover, the proposed method can be used in the case of both separable and non-separable parametric specifications of the correlation function of the underlying Gaussian Random Field. We describe earthquake sequences comparing several Cox model specifications. 相似文献
16.
Adelfio Giada Siino Marianna Mateu Jorge Rodr&#;guez-Cort&#;s Francisco J. 《Stochastic Environmental Research and Risk Assessment (SERRA)》2020,34(1):149-168
Stochastic Environmental Research and Risk Assessment - Diagnostics of goodness-of-fit in the theory of point processes are often considered through the transformation of data into residuals as a... 相似文献
17.
Marianna?SiinoEmail author Giada?Adelfio Jorge?Mateu Marcello?Chiodi Antonino?D’Alessandro 《Stochastic Environmental Research and Risk Assessment (SERRA)》2017,31(7):1633-1648
Earthquakes are one of the most destructive natural disasters and the spatial distribution of their epicentres generally shows diverse interaction structures at different spatial scales. In this paper, we use a multi-scale point pattern model to describe the main seismicity in the Hellenic area over the last 10 years. We analyze the interaction between events and the relationship with geological information of the study area, using hybrid models as proposed by Baddeley et al. (2013). In our analysis, we find two competing suitable hybrid models, one with a full parametric structure and the other one based on nonparametric kernel estimators for the spatial inhomogeneity. 相似文献