von Rad, Ulrich; Botz, Reiner (1987): Texture, geochemistry, isotope composition, petrography and epoch at DSDP Site 93-603 [dataset publication series]. PANGAEA, https://doi.org/10.1594/PANGAEA.789138, Supplement to: von Rad, U; Botz, R (1987): Authigenic Fe-Mn carbonates in Cretaceous and Tertiary sediments of the continental rise off eastern North America, Deep Sea Drilling Project Site 603. In: van Hinte, JE; Wise, SW Jr; et al. (eds.), Initial Reports of the Deep Sea Drilling Project, Washington (U.S. Govt. Printing Office), 93, 1061-1077, https://doi.org/10.2973/dsdp.proc.93.144.1987
Always quote citation above when using data! You can download the citation in several formats below.
Abstract:
Abundant Fe-Mn carbonate concretions (mainly siderite, manganosiderite, and rhodochrosite) were found in the hemipelagic claystones of Site 603 on the eastern North American continental rise. They occur as nodules, micronodules, or carbonate-replaced burrow fills and layers at a subbottom depth of between ~ 120 (Pliocene) and 1160 m (Albian-Cenomanian). In general, the Fe-Mn carbonate concretions form from CO3- produced by the microbiological degradation of organic matter in the presence of abundant Fe + or Mn + and very low S- concentrations. However, there is also some evidence for diagenetic replacement of preexisting calcite by siderite.
The carbon isotope composition of diagenetic Fe-Mn carbonate nodules is determined by CO2 reduction during methanogenesis. Carbonate nodules in Cretaceous sediments at sub-bottom depths of 1085 and 1160 m have distinctly lower d13C values (– 12.2 and - 12.9 per mil) than Neogene siderites, associated with abundant biogenic methane in the pore space (-8.9 to 1.7 per mil between 330 and 780 m depth). Since no isotopic zonation could be detected within individual nodules, we assume that the isotopic composition reflects more or less geochemical conditions at the present burial depth of the carbonate nodules. Carbonates did not precipitate within the zone of sulfate reduction (approximately 0.01 to 10 m), where all of the pyrite was formed. The oxygen isotope composition indicates precipitation from seawater-derived interstitial waters. The d18O values decrease with increasing burial depth from + 5.1 to - 1.2 per mil, suggesting successively higher temperatures during carbonate formation.
Project(s):
Deep Sea Drilling Project (DSDP)
Coverage:
Median Latitude: 35.494750 * Median Longitude: -70.028400 * South-bound Latitude: 35.494300 * West-bound Longitude: -70.028500 * North-bound Latitude: 35.495200 * East-bound Longitude: -70.028300
Date/Time Start: 1983-05-05T00:00:00 * Date/Time End: 1983-05-05T00:00:00
License:
Creative Commons Attribution 3.0 Unported (CC-BY-3.0)
Size:
2 datasets
Download Data
Datasets listed in this publication series
- von Rad, U; Botz, R (1987): (Table 1A) Texture, composition and geochemistry at DSDP Site 93-603. https://doi.org/10.1594/PANGAEA.789135
- von Rad, U; Botz, R (1987): (Table 1B) Stable isotope composition, petrography and epoch at DSDP Site 93-603. https://doi.org/10.1594/PANGAEA.789136