Universität zu Köln

Zanella, Elena ORCID: 0000-0002-9508-7211, Tema, Evdokia, Lanci, Luca ORCID: 0000-0002-3389-6371, Regattieri, Eleonora ORCID: 0000-0003-0089-4027, Isola, Ilaria ORCID: 0000-0002-3911-4676, Hellstrom, John C., Costa, Emanuele, Zanchetta, Giovanni, Drysdale, Russell N. and Magri, Federico (2018). A 10,000 yr record of high-resolution Paleosecular Variation from a flowstone of Rio Martino Cave, Northwestern Alps, Italy. Earth Planet. Sci. Lett., 485. S. 32 - 43. AMSTERDAM: ELSEVIER SCIENCE BV. ISSN 1385-013X

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Abstract

Speleothems are potentially excellent archives of the Earth's magnetic field, capable of recording its past variations. Their characteristics, such as the continuity of the record, the possibility to be easily dated, the almost instantaneous remanence acquisition and the high time-resolution make them potentially unique high-quality Paleosecular Variation (PSV) recorders. Nevertheless, speleothems are commonly characterized by low magnetic intensities, which often limits their resolution. Here we present a paleomagnetic study performed on two cores from a flowstone from the Rio Martino Cave (Western Alps, Italy). U/Th dating indicates that the flowstone's deposition covers almost the entire Holocene, spanning the period ca. 0.5-9.0 Ica, while an estimation of its mean growth rate is around 1 mm per 15 years. The flowstone is composed of columnar calcite, characterized by a highly magnetic detrital content from meta-ophiolites in the cave's catchment. This favorable geological context results in an intense magnetic signal that permits the preparation and measurement of thin (similar to 3 mm depth equivalent) samples, each representing around 45 yr. The Characteristic Remanent Magnetization (ChRM), isolated after systematic stepwise Alternating Field demagnetization, is well defined, with Maximum Angular Deviation (MAD) generally lower than 10 degrees. Paleomagnetic directional data allow the reconstruction of the PSV path during the Holocene for the area. Comparison of the new data with archeomagnetic data from Italian archeological and volcanic records and using the predictions of the SHA.DIF.14k and pfm9k.1 a global geomagnetic field models shows that the Rio Martino flowstone represents an excellent recorder of the Earth's magnetic field during the last 9,000 years. Our high resolution paleomagnetic record, anchored by a high-quality chronology, provides promising data both for the detection of short term geomagnetic field variations and for complementing existing regional PSV curves for the prehistoric period, for which well-dated data are still scarce. (C) 2018 Elsevier B.V. All rights reserved.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Zanella, Elena UNSPECIFIED orcid.org/0000-0002-9508-7211 UNSPECIFIED Tema, Evdokia UNSPECIFIED UNSPECIFIED UNSPECIFIED Lanci, Luca UNSPECIFIED orcid.org/0000-0002-3389-6371 UNSPECIFIED Regattieri, Eleonora UNSPECIFIED orcid.org/0000-0003-0089-4027 UNSPECIFIED Isola, Ilaria UNSPECIFIED orcid.org/0000-0002-3911-4676 UNSPECIFIED Hellstrom, John C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Costa, Emanuele UNSPECIFIED UNSPECIFIED UNSPECIFIED Zanchetta, Giovanni UNSPECIFIED UNSPECIFIED UNSPECIFIED Drysdale, Russell N. UNSPECIFIED UNSPECIFIED UNSPECIFIED Magri, Federico UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-195275
DOI:	10.1016/j.epsl.2017.12.047
Journal or Publication Title:	Earth Planet. Sci. Lett.
Volume:	485
Page Range:	S. 32 - 43
Date:	2018
Publisher:	ELSEVIER SCIENCE BV
Place of Publication:	AMSTERDAM
ISSN:	1385-013X
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language GEOMAGNETIC SECULAR VARIATION; EARTHS MAGNETIC-FIELD; PALAEOSECULAR VARIATION; ELECTRON-MICROSCOPY; HOLOCENE; SPELEOTHEM; ROCK; STALAGMITES; PALEOMAGNETISM; COERCIVITY Multiple languages Geochemistry & Geophysics Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/19527