Hu Xiumian (2008): Aptian-Albian cyclic oceanic red beds in the ODP Hole 1049C, North Atlantic

Leg/Site/Hole:
ODP 171B
ODP 171A 1049
Identifier:
2009-022253
georefid

Creator:
Hu Xiumian
Nanjing University, Nanjing, China
author

Identification:
Aptian-Albian cyclic oceanic red beds in the ODP Hole 1049C, North Atlantic
2008
In: Anonymous, 33rd international geological congress; abstracts
[International Geological Congress], [location varies], International
33
The Aptian-Albian sediments in the ODP Leg 171B Hole 1049C are characterized by high frequency of cyclothems between oceanic red and grey/white marls. To better understand the origin of these red beds, research on the mineralogy, sedimentology and geochemistry and is 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 which are responsible for the red coulor 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 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 magnetite composition. X-ray diffraction results reveal that all of the samples, no matter what colors they are, contain illite, kaolinite, chlorite and montmorillonite. Their distributions have no correlation with the colors, which probably reflects stable climate of the resource area at that time when deposited. The samples from Hole 1049C show 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 low temperature. Brown samples have low carbonate content. Furthermore, our data shows that higher oxygen isotope and slightly lower carbon isotopes values of fine fraction carbonate are correlated with red interval. Neodymium isotopes of whole rocks stay relatively stable through the Aptian-Albian core. We suggested that probably oxidizing environment with high content of dissolved oxygen near water-sediment interfaces to which red beds are corresponding, results most probably from low rate accumulation of organic materials.
English
Coverage:Geographic coordinates:
North:30.0832
West:-76.0644East: -76.0644
South:30.0832

Stratigraphy; Albian; Aptian; Atlantic Ocean; Blake Nose; Blake Plateau; C-13/C-12; carbon; clastic rocks; Cretaceous; cyclothems; depositional environment; isotope ratios; isotopes; Leg 171B; lithofacies; Lower Cretaceous; magnetic properties; magnetic susceptibility; marine environment; Mesozoic; North Atlantic; Ocean Drilling Program; ODP Site 1049; paleomagnetism; planar bedding structures; red beds; sedimentary rocks; sedimentary structures; stable isotopes;

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