scholarly journals Rock magnetism of tiny exsolved magnetite in plagioclase from a Paleoarchean granitoid in the Pilbara craton

2015 ◽  
Vol 16 (1) ◽  
pp. 112-125 ◽  
Author(s):  
Yoichi Usui ◽  
Takazo Shibuya ◽  
Yusuke Sawaki ◽  
Tsuyoshi Komiya
Keyword(s):  
Rock Magnetism ◽  
Pilbara Craton ◽  
Exsolved Magnetite

Development of the Archaean Mallina Basin, Pilbara Craton, northwestern Australia; a study of detrital and inherited zircon ages

2001 ◽  
Vol 141-142 ◽  
pp. 79-94 ◽  
Author(s):  
R.H Smithies ◽  
D.R Nelson ◽  
G Pike
Keyword(s):  
Northwestern Australia ◽  
Pilbara Craton

Report from IUGG Assembly: IAGA session on rock magnetism of fine particles

Eos ◽  
1980 ◽  
Vol 61 (24) ◽  
pp. 493
Author(s):  
E. R. Deutsch
Keyword(s):  
Fine Particles ◽  
Rock Magnetism

Rock magnetism and magnetostratigraphy of the loess-sol series of Ukraine (Roksolany, Boyanychi, and Korshev sections)

2017 ◽  
Vol 53 (6) ◽  
pp. 864-884 ◽  
Author(s):  
V. G. Bakhmutov ◽  
A. Yu. Kazanskii ◽  
G. G. Matasova ◽  
D. V. Glavatskii
Keyword(s):  
Rock Magnetism

3.43 billion-year-old stromatolite reef from the Pilbara Craton of Western Australia: Ecosystem-scale insights to early life on Earth

2007 ◽  
Vol 158 (3-4) ◽  
pp. 198-227 ◽  
Author(s):  
Abigail C. Allwood ◽  
Malcolm R. Walter ◽  
Ian W. Burch ◽  
Balz S. Kamber
Keyword(s):  
Western Australia ◽  
Early Life ◽  
Life On Earth ◽  
Pilbara Craton

UPb zircon geochronology of Archaean felsic units in the Marble Bar region, Pilbara Craton, Western Australia

1992 ◽  
Vol 56 (3-4) ◽  
pp. 169-189 ◽  
Author(s):  
R.I. Thorpe ◽  
A.H. Hickman ◽  
D.W. Davis ◽  
J.K. Mortensen ◽  
A.F. Trendall
Keyword(s):  
Western Australia ◽  
Zircon Geochronology ◽  
Pilbara Craton

The Physical Principles of Rock Magnetism (Developments in Solid Earth Geophysics, 2)

1974 ◽  
Vol 12 (4) ◽  
pp. 297-298
Author(s):  
R.S. Bhatal
Keyword(s):  
Solid Earth ◽  
Rock Magnetism ◽  
Physical Principles

AMS of strained shales fragments: a fast way to quantify the matrix damage

2021 ◽  
Author(s):  
Francho Gracia Puzo ◽  
Charles Aubourg ◽  
Antonio Casas Sainz
Keyword(s):  
Rock Magnetism ◽  
Magnetic Fabric ◽  
Magnetic Minerals ◽  
Statistical Characterization ◽  
Main Thrust ◽  
Rock Fragments ◽  
Scalar Data ◽  
The Matrix ◽  
Degree Of Anisotropy

<p>With the objective of mapping strain on the footwall of a thrust in an orogenic context (Leyre thrust, South Pyrenean Range), more than 1500 unoriented shale fragments (0.7-6.2 g) have been collected. Scalar data (degree of anisotropy P and shape parameter T), together with ellipse of confidence of individual axes provide a proxy of strain acquired by shales in the footwall of the main thrust (Saur et al. 2020).</p><p>Normally, sampling is done by two methods: collecting oriented decimetric hand specimens; or drilling 2.5 cm diameter cylinders. This presents the advantage to deal with oriented samples. However, those techniques are time consuming and it is difficult to collect numerous samples in loose materials such as shales. On the contrary, collecting rock fragments presents the net advantage to provide a much better statistical characterization of the site.</p><p>All samples belong to the Eocene shaly formations from the Jaca Basin. Rock fragments are mostly fractured according to the bedding and/or cleavage surfaces. We demonstrate that the anisotropy parameters P and T maintain their values, regardless the shape and size of fragments. Rock magnetism indicates that AMS is primarily governed by illite, with little contribution of magnetite. AMS provides therefore a proxy of illite organisation within the matrix.</p><p>In the footwall of the Sierra de Leyre we have defined up to 7 parallel sampling sections, whose traces are perpendicular to the direction of the main thrust. On average, each section is made up of about 10 sampling sites and about 15 fragments are collected per site, covering a few square meters.</p><p>We are restricted by the dimensions of AGICO holders (8cm<sup>3</sup> for cubes, or 10 cm<sup>3</sup> for cylinders). It is possible to use an empty 10 cm<sup>3</sup> cylinder, which can be filled with smaller fragments of rock. The automatic rotator allows a fast and precise description of the AMS tensor. We removed from analysis low susceptibility, carbonate-rich samples, that show a higher variety of magnetic minerals. All sites present homogenous results at the site scale, but with significant differences with respect to strain. P and T parameters are very sensitive to strain as illite is the dominant carrier. In addition, the ellipse of confidence of the minimum AMS axis (K3) provides a sensitive proxy to characterize the competition between bedding and cleavage.</p><p>The comparison between the different sections allows to map the areas of damage linked to the propagation of faults associated with the folds. 5 stages of development of the magnetic fabric allows the detection of damage gradients. The mapping has allowed the identification of hidden faults.    </p><p>This new approach is very promising, and allows much more detailed samplings in difficult areas, providing more robust statistical description of scalar AMS data. This methodology could be useful for the study of outcrops that are difficult to access, and more interestingly, from borehole cuttings.</p>

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