Research activity

Analytical applications

Geology

Contact: Imre Uzonyi, uzonyi (at) atomki.hu

Part of our studies is focussed to the analysis of microscopic-sized (<1 mm), usually rounded, magnetizable geological objects: so called magnetic spherules [50]. Their origin has not been entirely determined, although it has been restricted to extraterrestrial (cosmic dust or meteoritic impact), igneous (volcanic or metamorphic), and industrial processes. Extraterrestrial spherules may provide clues to global geological correlations during the history of the Earth as well as they can be indicators of meteoritic impact.


Magnetic spherule

An important period in the Earth's history was the transitional time between Permian and Triassic era. Then a global crisis had almost exterminated the life of the Paleozoic age and new living creatures appeared at the onset of the Triassic era. In a theory developed by a Hungarian team (MÁFI - ATOMKI - ELTE - Konkoly Observatory) it was supposed that this catastrophe had been originated by a nearby supernova explosion. A strong experimental evidence corroborating this hypotheses is that tiny (3-20 µm) magnetic spherules were found in a lot of Upper Permian rocks of the Earth. They were identified by PIXE to be of cosmic origin and their presence can be explained by supernova explosion [51,52].

Impact craters on the Earth created by incident asteroids, comets and meteorites are important sources of extraterrestrial materials. Thus they play a special role in the study of the composition of the primordial planetary matter and cosmic parent bodies. The most famous and well-preserved meteorite crater is the Barringer Meteor Crater in Arizona, USA. Supposedly, it was created by an iron meteorite. Impact materials collected at the crater have been studied extensively from a mineralogical point of view in ATOMKI - University of Debrecen collaboration.

It is particularly important to analyse their iron-rich inclusions (S-Fe-Ni-Cu-systems) attributable to the meteorite as well as the concentration of Platinum Group Elements (Ru, Rh, Pd, Os, Ir, Pt). In this atomic number region SRXRF offers superior detection limits (down to the sub-ppm level [53]), therefore SRXRF technique was also applied complementary to PIXE [54].

References:

[50] Gy. Szöőr, Z. Elekes, P. Rózsa, I. Uzonyi, J. Simulák, Á.Z. Kiss: Magnetic spherules: Cosmic dust or markers of a meteoritic impact?. Nucl. Instr. and Meth. B 181 (2001) 557

[51] Cs.H. Detre, I. Tóth, Gy. Don, Á.Z. Kiss, I. Uzonyi, P. Bodó, Z. Schleder: The Permian-Triassic supernova impact. Meteoritics and Planetary Science 34 (1999) A125

[52] Cs.H. Detre, I. Tóth, Gy. Don, Á.Z. Kiss, I. Uzonyi, P. Bodó, Zs. Schléder: The paleozoic came to end by the biggest train of disasters known in the Earth's history. Terrestrial and Cosmic Spherules. Proceedings of the 1998 Annual Meeting TECOS. Ed.: Csaba H. Detre. Bp., Akadémiai Kiadó (2000) p. 45

[53] I. Uzonyi, Gy. Szöőr, B. Vekemans, L. Vincze, P. Rózsa, Gy. Szabó, A. Somogyi, F. Adams, Á.Z. Kiss: Application of combined micro-proton-induced Xray emission and micro-synchrotron radiation X-ray fluorescence techniques for the characterization of impact materials around Barringer Meteor Crater, Spectrochimica Acta Part B - Atomic Spectroscopy 59 (2004) 1717

[54] I. Uzonyi, Gy. Szöőr, P. Rózsa, B. Vekemans, L. Vincze, F. Adams, M. Drakopoulos, A. Somogyi, Á.Z. Kiss: Characterization of impact materials around Barringer Meteor Crater by micro-PIXE and micro-SRXRF techniques, Nucl. Instr. and Meth. B 219 (2004) 555