Results 41 to 50 of about 2,734 (234)

An Assessment of the Magmatic Conditions of Late Neoproterozoic Collisional and Post-collisional Granites From the Guéra Massif, South-Central Chad

open access: yesFrontiers in Earth Science, 2020
The Guéra Massif, in South-Central Chad hosts granitic rocks that were emplaced during distinct intervals (595–590; ∼570; ∼560 Ma) of the Late Ediacaran Central African Orogenic Belt.
Chi Thi Pham   +3 more
doaj   +1 more source

Determination of trace element profiles in coarse-grained minerals by external millibeam PIXE - A schorl tourmaline study [PDF]

open access: yesBulletin of the Geological Society of Finland, 1995
The thick-target PIXE technique was applied to direct analysis of trace elements in tourmaline minerals. Analyses of these minerals with conventional wet-chemical methods are difficult and time consuming.
A. Lindroos   +4 more
doaj   +1 more source

Investigation of the failure characteristics of fissure tunnels under dynamic and static combinations

open access: yesDeep Underground Science and Engineering, EarlyView.
This article aims to investigate the dynamic fracture response of fractured tunnel models under zero geological stress through physical experiments and numerical simulations. It further simulates the dynamic fracture characteristics of fractured tunnel models under geological stress ranging from 0 to 2.5 MPa using the numerical software AUTODYN ...
Peng Ying   +7 more
wiley   +1 more source

Geology and geochemistry of the Redrock Granite and anorthosite xenoliths (Proterozoic) in the northern Burro Mountains, Grant County, New Mexico, USA [PDF]

open access: yesBulletin of the Geological Society of Finland, 2002
Mineral ages from the A-type granites and anorthosite xenoliths in the Redrock area in the northwestern Burro Mountains in southwestern New Mexico cluster around ~1220–1225 Ma and provide yet another example of bimodal igneous activity during this time ...
V.T. McLemore   +5 more
doaj   +1 more source

Effect of confining pressure on fracture characteristics and mineralogical behavior of tight sandstone specimens after hydraulic fracturing

open access: yesDeep Underground Science and Engineering, EarlyView.
Hydraulic fracturing in tight sandstone and fracture propagation characteristics using backscattered electron‐scanning electron microscope (BSE‐SEM) images. Abstract This study focuses on hydraulic fracturing experiments conducted under triaxial conditions on tight sandstone specimens from Shivpuri district, Madhya Pradesh, India.
Pankaj Rawat, Narendra Kumar Samadhiya
wiley   +1 more source

Geologic structure and composition of Munilkan massif Verkhoyansk-Kolyma orogenic area

open access: yesЛитосфера, 2015
This article presents the results of detailed study of geologic structure and composition of Munilkan massif of the Main batholith belt of Verkhoyansk-Kolyma mesozoides (Tas-Khayakhtakh Ridge).
V. A. Trunilina   +2 more
doaj  

Physicochemical conditions of the formation of the Larino granite-gneiss dome (South Ural)

open access: yesGeoresursy
The Larino granite-gneiss dome is located on the border of the Aramil-Sukhtelya and Magnitogorsk megazones and is a two-headed anticlinal structure, the nuclear parts of which are composed of granitoids of the Pervomai and Larino massifs, and their ...
V. I. Snachev   +2 more
doaj   +1 more source

Mafic-silicic magma interaction in the layered 1.87 Ga Soukkio Complex in Mäntsälä, southern Finland [PDF]

open access: yesBulletin of the Geological Society of Finland, 2002
The Svecofennian layered Soukkio Complex (1.87 Ga) in Mäntsälä, southern Finland, consists of layered tholeiitic gabbro and porphyritic calc-alkaline monzonite, quartz monzonite and granite, mingled together.
T.T. Eerola
doaj   +1 more source

Creep properties and constitutive model of diabase in deep water conveyance tunnels

open access: yesDeep Underground Science and Engineering, EarlyView.
The axial and lateral creep characteristics of diabase were analyzed based on compression creep tests. The nonlinear viscoelastic‐plastic model capable of describing the whole creep process was established based on the fractional derivative and damage theories.
Zhigang Tao   +5 more
wiley   +1 more source

The Orivesi granite batholith, Southern Central Finland - characteristics and emplacement [PDF]

open access: yesBulletin of the Geological Society of Finland, 1996
The Orivesi granite batholith is situated in an E-W trending belt of granite intrusions along the southern margin of the Central Finland Granitoid Complex (CFGC).
O. Selonen, C. Ehlers
doaj   +1 more source

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