کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4678727 1634859 2010 13 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Testing the accuracy of absolute intensity estimates of the ancient geomagnetic field using copper slag material
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات علوم زمین و سیاره ای (عمومی)
پیش نمایش صفحه اول مقاله
Testing the accuracy of absolute intensity estimates of the ancient geomagnetic field using copper slag material
چکیده انگلیسی

The Middle-Eastern copper slag is a promising new material for studying intensity variations in the geomagnetic field with high resolution and precision. The purpose of this study is to test the accuracy of archaeointensity estimates determined using copper slag by addressing two questions: 1) “Does slag material display the magnetic properties required for valid Thellier experiments?” and 2) “What is the accuracy of the archaeointensity estimates derived from Thellier-style experiments on optimal samples?” We address the first question through a comprehensive microscopic and magnetic study of representative archaeological slag samples in order to identify the properties responsible for optimal behavior in Thellier experiments. To address the second question, we reproduced slag samples in the laboratory under controlled magnetic fields and analyzed them using the same IZZI paleointensity technique used for the ancient slag. Microscopic analyses of the archaeological slag show that ferromagnetic phases occur as three-dimensional dendritic structures whose branches consist of submicron-elongated particles. Magnetic analyses show that these dendrites behave as an assemblage of shape-controlled, single-domain-like particles and that their magnetization is thermoremanent. We conclude that slag material can be magnetically suitable for valid Thellier experiments. The laboratory-produced slag material demonstrated similar magnetic and mineralogical properties as the archaeological slag. IZZI experiments showed that non-linear TRM acquisition, even at field strengths similar to Earth's, and TRM anisotropy are important factors to monitor during paleointensity studies of slag material. Anisotropy and non-linearity are probably related to the dendritic shape of the oxide grains. Intensity estimates derived from three laboratory-produced slag samples demonstrated accuracy to within ∼ 5% after applying the required corrections.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Earth and Planetary Science Letters - Volume 290, Issues 1–2, 15 February 2010, Pages 201–213
نویسندگان
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