کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1036771 943897 2010 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Holocene sulphur-rich palaeochannel sediments: diagenetic conditions, magnetic properties and archaeological implications
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد دانش مواد (عمومی)
پیش نمایش صفحه اول مقاله
Holocene sulphur-rich palaeochannel sediments: diagenetic conditions, magnetic properties and archaeological implications
چکیده انگلیسی

Extensive aggregate extraction in the middle Trent valley, England, has revealed a sequence of Holocene palaeochannels associated with nationally important, and predominantly organic, archaeological remains. This paper reports observations of hyper-acidity (below pH 2), high natural magnetism and metallic sphaerules (framboids) in Holocene palaeochannel sediments at two sites in the middle Trent valley. These properties are associated with high natural remanent magnetism which has allowed the successful palaeomagnetic dating of palaeochannel fills at one of these sites (Hemington). These sediment properties are the result of the formation of ferromagnetic iron sulphides, including griegite, under conditions of high sulphur availability (from groundwater) in the presence of metallic ions and organic matter under low redox conditions, with later oxidation producing the extreme natural acidity through oxidation of disulphide (pyrite). These findings explain why, under certain groundwater conditions, alluvial palaeochannel sediments can carry post-depositional remanent magnetisation and be suitable for palaeomagnetic dating. The low pH may also be beneficial in the initial stage of wood preservation and if the sediments remain waterlogged, but probably not retard decomposition after drainage and acidification, a process that is increasingly being recognised as a threat to archaeological sites in wetland environments.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Archaeological Science - Volume 37, Issue 1, January 2010, Pages 21–29
نویسندگان
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