georefid:2013-002828SEDIS Publication Catalogue

ana.macario@awi.de

http://sedis.iodp.org/pub-catalogue/informationpointOfContact2013-07-08T00:00:00Zhttp://sedis.iodp.org/pub-catalogue/index.php?id=2013-0028282008-01-01publicationgeorefid:2013-002828Han ZhiyanNanjing University, Department of Earth Sciences, Nanjing, ChinaauthorHu XiumianChina University of Geosciences, ChinaauthorJi JunfengauthorHuang YongjianauthorHuang ZhichengauthorScience Press, Beijing, ChinapublisherdocumentHardcopyDizhixue Bao = Acta Geologica Sinica82 (1)124-132The Aptian-Albian sediments in the ODP Leg 171B Hole 1049C are characterized by a high frequency of cyclothems between oceanic red beds and gray, or white depositions. To better understand the origin of the red beds, research on the mineralogy, geochemistry and sedimentology was carried out by way of Diffuse Reflectance Spectrometry (DRS), magnetic susceptibility and reactive iron analysis. Our data show that hematite and goethite are the minerals responsible for the red color of the red beds. Characteristic peaks of hematite and goethite occur in brown and orange samples, and their averaged FeR/FeT values are 0.23 and 0.24 respectively, obviously different from those of other samples. The good positive correlation between magnetic susceptibility and red beds suggest that the magnetic susceptibility changes due to the variety of the hematite or maghemite composition. X-ray Diffraction results reveal that all of the samples, no matter what color they are, contain illite, kaolinite, chlorite and montmorillonite. Their distribution has no correlation with the color, which probably reflects stable climate of the source area at that time when deposited. The samples from Hole 1049C show a high frequency cyclothems in orange, brown, white, gray, and the interface of different colors is clear, which indicates that hematite and goethite are the results of oxygenation at a low temperature. Brown samples with a low carbonate content probably indicates that oxidizing environment to which red beds are corresponding, results from a low rate accumulation of organic materials.completedSedimentary petrologyAlbianAptianAtlantic OceanBlake NoseBlake Plateauclastic rocksclay mineralsclaystoneCretaceoushematiteLeg 171BLower CretaceousmaghemiteMesozoicmineral compositionNorth AtlanticOcean Drilling ProgramODP Site 1049oxidessedimentary rockssheet silicatessilicatesurn:org.iodp:exp:171BurnlargerWorkCitationcampaignurn:org.iodp:exp:171A:site:1049urnlargerWorkCitationstudyurn:org.iodp:exp:171AurnlargerWorkCitationcampaignChinesegeoscientificInformation-76.0644-76.064430.083230.0832