MAGMA FLOW AND INFLATION WITHIN THE WAI’ANAE VOLCANO (OAHU, HAWAII, USA): IMPLICATIONS FROM MAGNETIC FABRIC DATA OF DIKES

2017 ◽  
Author(s):  
Emilio Herrero-Bervera ◽  
◽  
Bernard Henry ◽  
Mario Moreira
Keyword(s):  
Magnetic Fabric ◽  
Magma Flow

Anisotropy of magnetic susceptibility in alkaline-ultramafic dikes of the Kotuy river valley: Reconstruction of magma transport during the Siberian Traps emplacement

2020 ◽  
Author(s):  
Anton Latyshev ◽  
Victor Chmerev ◽  
Victor Zaitsev
Keyword(s):  
River Valley ◽  
Magnetic Fabric ◽  
Ultramafic Rocks ◽  
Limited Area ◽  
Magmatic Activity ◽  
Contact Zones ◽  
Magma Flow ◽  
Siberian Traps ◽  
Magmatic Stage ◽  
Alkaline Lamprophyres

<p>Products of the Permian-Triassic magmatic activity in the Kotuy river valley consist of two contrasting in composition groups: 1) tholeiitic basalts, similar to the main volume of the Siberian Traps; 2) alkaline-ultramafic rocks which are extremely rare in other regions of the Siberian platform. Alkaline lavas and tuffs in the Kotuy river valley are exposed only in limited area (Arydzhangsky and Khardakhsky formations), however, multiphase circular plutons (Kugda, Odikhincha) and swarms of radial and parallel dikes marks the essentially wider territory of the manifestation of alkaline magmatic activity.</p><p>Here we present the preliminary results of the investigation of AMS in the dike complex of alkaline lamprophyres from the Kotuy river valley. The majority of dikes demonstrate I-type of the magnetic fabric, when the medium axes K2 of AMS ellipsoid is orthogonal to the contact of intrusion. In dikes where the minimal axis K3 is subvertical and maximal axis K1 is flat, we interpret this magnetic fabric as a result of cooling of the static magma column after the emplacement in the setting of horizontal extension (Park et al., 1988; Raposo and Ernesto, 1995). Also, N-type and R-type of magnetic fabric were identified as well. In some intrusions, the orientation of the axes of AMS ellipsoid changes from the contact zones to the inner part if intrusion. In this case, we used data from the contact zones for the magma flow reconstruction.</p><p>Analysis of the maximal axis K1 orientation in different dikes showed that in majority of bodies it shallowly plunges to the west. This corresponds to the lateral magma flow from west to east during the emplacement. Consequently, formation of the studied dikes is not directly related to Kugda pluton, which is located 8 km eastward. The emplacement of dikes occurred from the magmatic center located westward from the Kotuy river valley and is not associated with any known large massifs. Petrographic similarity of the studied dikes to the lavas of Arydzhangsky formation allows us to suggest that they are coeval. This implies the wider area of manifestation of the Arydzhangsky magmatic stage.</p><p>This work was supported by RFBR (projects 18-35-20058, 18-05-70094, 17-05-01121 and 20-05-00573).</p>

Magnetic fabric and tectonic setting of the Early to Middle Jurassic felsic dykes at Pitt Point and Mount Reece, eastern Graham Land, Antarctica

2011 ◽  
Vol 24 (1) ◽  
pp. 45-58 ◽  
Author(s):  
Jiří Žák ◽  
Igor Soejono ◽  
Vojtěch Janoušek ◽  
Zdeněk Venera
Keyword(s):  
Stress Field ◽  
Middle Jurassic ◽  
Large Scale ◽  
Tectonic Setting ◽  
Local Stress ◽  
Weddell Sea ◽  
Magnetic Fabric ◽  
Magma Source ◽  
Magma Flow ◽  
North Eastern

AbstractAt Pitt Point, the east coast of Graham Land (Antarctic Peninsula), the Early to Middle Jurassic (Toarcian–Aalenian) rhyolite dykes form two coevally emplaced NNE–SSW and E–W trending sets. The nearly perpendicular dyke sets define a large-scale chocolate-tablet structure, implying biaxial principal extension in the WNW–ESE and N–S directions. Along the nearby north-eastern slope of Mount Reece, the WNW–ESE set locally dominates suggesting variations in the direction and amount of extension. Magnetic fabric in the dykes, revealed using the anisotropy of magnetic susceptibility (AMS) method, indicates dip-parallel to dip-oblique (?upward) magma flow. The dykes are interpreted as representing sub-volcanic feeder zones above a felsic magma source. The dyke emplacement was synchronous with the initial stages of the Weddell Sea opening during Gondwana break-up, but it remains unclear whether it was driven by regional stress field, local stress field above a larger plutonic body, or by an interaction of both.

Magma flow revealed by magnetic fabric in the Okavango giant dyke swarm, Karoo igneous province, northern Botswana

2008 ◽  
Vol 170 (3-4) ◽  
pp. 247-261 ◽  
Author(s):  
C. Aubourg ◽  
G. Tshoso ◽  
B. Le Gall ◽  
H. Bertrand ◽  
J.-J. Tiercelin ◽  
...  
Keyword(s):  
Magnetic Fabric ◽  
Dyke Swarm ◽  
Magma Flow ◽  
Igneous Province

scholarly journals ANISOTROPY OF MAGNETIC SUSCEPTIBILITY (AMS) IN VOLCANIC FORMATIONS: THEORY AND PRELIMINARY RESULTS FROM RECENT VOLCANICS OF BROADER AEGEAN.

2004 ◽  
Vol 36 (3) ◽  
pp. 1308 ◽  
Author(s):  
I. Zananiri ◽  
D. Kondopoulou
Keyword(s):  
Magnetic Susceptibility ◽  
Flow Direction ◽  
Source Region ◽  
Physical Property ◽  
Anisotropy Of Magnetic Susceptibility ◽  
Magnetic Fabric ◽  
Local Flow ◽  
Magma Flow ◽  
Preliminary Results ◽  
Scalar Properties

The anisotropy of magnetic susceptibility (AMS) is a physical property of rocks widely used in petrofabric studies and other applications. It is based on the measurement of low-field magnetic susceptibility in different directions along a sample. From this process several scalar properties arise, defining the magnitude and symmetry of the AMS ellipsoid, along with the magnetic foliation, namely the magnetic fabric. Imaging the sense of magma flow in dykes is an important task for volcanology; the magnetic fabric provides a fast and accurate way to infer this flow direction. Moreover, the AMS technique can be used in order to distinguish sills and dykes, a task that is almost impossible by using only field observations. Finally in the case of lava flows, the method can be applied to define the local flow conditions and to indicate the position of the "paleo" source region. However, this technique is quite new in Greece. Some preliminary results from volcanic formations of continental Greece and Southern Aegean are presented (Aegina, Almopia, Elatia, Gavra, Kos, Patmos, Samos, Samothraki and Santorini).

Magnetic fabric of Devonian and Precambrian dikes from the northeastern Kola Peninsula, Russia

2021 ◽  
Author(s):  
Sofya Fursova ◽  
Roman Veselovskiy
Keyword(s):  
Magnetic Susceptibility ◽  
Spatial Distribution ◽  
Kola Peninsula ◽  
Magnetic Fabric ◽  
Laboratory Studies ◽  
Magma Flow ◽  
Northeastern Part ◽  
Geological Age ◽  
First Results ◽  
Magma Sources

<p>Nowadays, anisotropy of magnetic susceptibility (AMS) is a very widespread method to investigate the magnetic fabric of the rocks. AMS studies provide the information on the magma flow during formation of intrusives (dikes and sills) based on the orientation of the AMS ellipsoid. In this work we present the results of the AMS measurements of Devonian, Paleoproterozoic and Neoarchean dikes, which are located on the northeastern part of the Kola Peninsula. We use these data to reconstruct the direction of magma flow with the final aim to reconstruct the spatial distribution of the magma sources.</p><p>Laboratory studies of AMS were carried out on 1282 samples representing 102 dikes. At this stage, all studied dikes were typified based on their geological age and type of AMS (normal, reversed, intermediate). It is shown that not all the studied intrusive bodies retained the primary magnetic fabric and only a few of them can be used to reconstruct the position of magmatic centers and are promising for obtaining reliable paleomagnetic data. We also present the first results of interpretation of the direction of the magma flow during dike swarms forming.</p><p>The study is supported by the grant of RSF #16-17-10260.</p>

Sign in / Sign up

Export Citation Format

Share Document