scholarly journals Mantle magmatic events indicated by zoned olivine and pyroxene compositional variations in a composite mantle xenolith from Lashaine Volcano, Tanzania

2019 ◽  
Keyword(s):  
Mantle Xenolith ◽  
Compositional Variations

Microdomains in BaFeO3-y (0.35 < y < 0.50)

1990 ◽  
Vol 48 (4) ◽  
pp. 780-781
Author(s):  
M. Vallet-Regí ◽  
M. Parras ◽  
J.M. González-Calbet ◽  
J.C. Grenier
Keyword(s):  
Electron Diffraction ◽  
Chemical Analysis ◽  
Monoclinic Phase ◽  
Orthorhombic Phase ◽  
Total Iron ◽  
Zone Axis ◽  
Electron Micrograph ◽  
X Ray Diffraction ◽  
X Ray ◽  
Compositional Variations

BaFeO3-y compositions (0.35<y<0.50) have been investigated by means of electron diffraction and microscopy to resolve contradictory results from powder X-ray diffraction data.The samples were obtained by annealing BaFeO2.56 for 48 h. in the temperature range from 980°C to 1050°C . Total iron and barium in the samples were determined using chemical analysis and gravimetric methods, respectively.In the BaFeO3-y system, according to the electron diffraction and microscopy results, the nonstoichiometry is accommodated in different ways as a function of the composition (y):In the domain between BaFeO2.5+δBaFeO2.54, compositional variations are accommodated through the formation of microdomains. Fig. la shows the ED pattern of the BaFeO2.52 material along thezone axis. The corresponding electron micrograph is seen in Fig. 1b. Several domains corresponding to the monoclinic BaFeO2.50 phase, intergrow with domains of the orthorhombic phase. According to that, the ED pattern of Fig. 1a, can be interpreted as formed by the superposition of three types of diffraction maxima : Very strong spots corresponding to a cubic perovskite, a set of maxima due to the superposition of three domains of the monoclinic phase along [100]m and a series of maxima corresponding to three domains corresponding to the orthorhombic phase along the [100]o.

scholarly journals Editorial for the Special Issue “Mineral Textural and Compositional Variations as a Tool for Understanding Magmatic Processes”

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 102
Author(s):  
Silvio Mollo ◽  
Flavio Di Stefano ◽  
Francesca Forni
Keyword(s):  
Magma Chamber ◽  
Igneous Rocks ◽  
Eruption Dynamics ◽  
Special Issue ◽  
Magma Chamber Processes ◽  
Magmatic Processes ◽  
Compositional Variations

This Special Issue of Minerals collects seven different scientific contributions highlighting how magma chamber processes and eruption dynamics studied either in the laboratory or in nature may ultimately control the evolutionary histories and geochemical complexities of igneous rocks [...]

Provenance and compositional variations of intra-caldera lake sediments at La Primavera, Jalisco, Western Mexico

2021 ◽  
pp. 103335
Author(s):  
Yam Zul Ernesto Ocampo-Díaz ◽  
Giovani Sosa-Ceballos ◽  
Ricardo Saucedo ◽  
José Luis Macías ◽  
Xavier Bolós ◽  
...  
Keyword(s):  
Lake Sediments ◽  
Western Mexico ◽  
Compositional Variations
Sign in / Sign up

Export Citation Format

Share Document