کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4741484 1641507 2014 13 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Paleointensity determination from São Miguel (Azores Archipelago) over the last 3 ka
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات فیزیک زمین (ژئو فیزیک)
پیش نمایش صفحه اول مقاله
Paleointensity determination from São Miguel (Azores Archipelago) over the last 3 ka
چکیده انگلیسی


• Paleointensity data from São Miguel are based on 13 lava flows from the last 3 ka.
• New data are internally consistent, and agree with Moroccan and European data.
• The inferred Virtual Axial Dipole Moments (VADMs) range from 68.2 to 163.5 ZAm2.
• Peak in field strength around 600 BC is comparable to the high values in Portugal.
• Latitudinal gradient in VADM from NW Africa and Europe between 100–1000 and 0–100 AD.

Paleointensity data from the Atlantic Ocean are rare. We present new paleointensity data from São Miguel (Azores Islands, Portugal) based on 20 paleomagnetic sites from 13 lava flows emplaced over the last 3000 years. Ten lava flows are radiocarbon dated, whereas three flows were paleomagnetically dated and one site was dated using stratigraphic relations. All the samples, previously investigated to recover paleodirections, were subjected to IZZI experiments. Importantly, the new data are internally consistent, agree with Moroccan and European datasets, and offer new constraints for global geomagnetic field models. Some of the ages of the paleomagnetically dated lava flows have been revised based on the intensity data presented here. The inferred Virtual Axial Dipole Moments (VADMs) range from 68.2 to 163.5 ZAm2. A peak in field strength with an estimated age of around 600 BC is well supported by two sites from the same flow (Furna), and is comparable to the high intensity values found in Portugal for the same age and the earlier field peak at about 1000 BC in the Levant. A gradient in VADM values with latitude from northwestern Africa and across Europe between 100 and 1000 AD is confirmed as well as its absence from between 0 to 100 AD.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Physics of the Earth and Planetary Interiors - Volume 234, September 2014, Pages 1–13
نویسندگان
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