Por favor utiliza este link para citar o compartir este documento: http://repositoriodigital.academica.mx/jspui/handle/987654321/80061
Título: Cooling rate effects on the magnetization of volcanic rocks: Some implications for paleointensity determination
Palabras clave: Cooling rate
paleointensity
volcanic rocks
rock magnetism
Fecha de publicación: 10-Jul-2012
Editorial: Geofísica internacional
Descripción: Effects of variation of cooling rate in the acquisition of thermoremanent magnetization (TRM) are analyzed on a suite of volcanic rocks. We use a three-step cooling rate experimental procedure applied at three distinct temperatures of TRM acquisition. Sixteen selected, thermally stable samples from Late Quaternary lava flows were given a pTRM (300°C) at a slow cooling rate. The acquired intensities were measured at room temperature. A second pTRM was applied to the same specimens using a fast cooling rate, and the acquired intensities were measured at room temperature. Finally a third pTRM was induced as in the first step, using a slow cooling rate. The procedure was repeated to create pTRM's at higher temperatures of 450° and 550°C. Corresponding percent variations between magnetization intensities acquired at slow-fast and at slow-slow cooling rates were calculated to investigate the influence of cooling rate on TRM intensity acquisition, and on TRM acquisition capacity. We observe values as high as 300 % in the former case (300 °C). Intensity of the ancient geomagnetic field obtained from volcanic rocks could be overestimated by at least 15% due to a variation in cooling rate normally employed in the laboratory, as compared to slower rates found in nature.
Other Identifiers: http://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S0016-71692006000200005
Aparece en las Colecciones:Geofísica Internacional

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