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United States Department of Agriculture

Agricultural Research Service

Title: In search of "Organ III" strata-a sedimentary record of the Medieval Warm Period (ca. AD 900 to 1300)

item Monger, H. Curtis
item Laney, Katie
item Frederickson, Eddie

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/1/2010
Publication Date: 10/14/2010
Citation: Monger, H., Laney, K., Fredrickson, E.L. 2010. In search of "Organ III" strata-a sedimentary record of the Medieval Warm Period (ca. AD 900 to 1300) [abstract]. 16th Biennial Mogollon Archaeology Conference, October 14-16, 2010, Las Cruces, New Mexico. p. 21-22.

Interpretive Summary:

Technical Abstract: The period AD 900 to 1300, internationally referred to as the Medieval Warm Period, is a critical time for the archaeological record of the Southwestern USA. During the Medieval Warm Period both alluvial and eolian sedimentation increased, but not to the magnitude of the middle Holocene (the Altithermal) or since Historical erosion began in the middle 1850s (the end of the Little Ice Age). Locally, the term “Organ III” has been given to the Medieval Warm Period allostratigraphic unit. It is a subtle unit stratigraphically between Altithermal sediments (Organ I) and Historical sediments. Diagnostic features for identifying these three units include the following: Organ I has distinct carbonate filaments and strong pedogenic structure; Organ III has very faint carbonate filaments and weak pedogenic structure; Historical deposits have no carbonate and sedimentary layers. The Organ III stratum is most obvious in geomorphic settings with contrasting parent materials or where an occupational surface underlies the Organ III unit. In addition to its archaeological significance, the Organ III unit provides information about the relative magnitude of current climate change as compared to prehistoric climate change.

Last Modified: 10/17/2017
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