de la Rocha, Christina L. (2003): Silicon isotope fractionation by marine sponges and the reconstruction of the silicon isotope composition of ancient deep water
Leg/Site/Hole:
Related Expeditions:
ODP 113
Identifier:
ID:
2003-046295
Type:
georefid
ID:
10.1130/0091-7613(2003)031<0423:SIFBMS>2.0.CO;2
Type:
doi
Creator:
Name:
de la Rocha, Christina L.
Affiliation:
University of Cambridge, Department of Earth Sciences, Cambridge, United Kingdom
Role:
author
Identification:
Title:
Silicon isotope fractionation by marine sponges and the reconstruction of the silicon isotope composition of ancient deep water
Year:
2003
Source:
Geology (Boulder)
Publisher:
Geological Society of America (GSA), Boulder, CO, United States
Volume:
31
Issue:
5
Pages:
423-426
Abstract:
The silicon isotope composition (delta (super 30) Si) of biogenic opal provides a view of the silica cycle at times in the past. Reconstructions require the knowledge of silicon isotope fractionation during opal biomineralization. The delta (super 30) Si of specimens of hexactinellid sponges and demosponges growing in the modern ocean ranged from -1.2 ppm to -3.7 ppm (n = 6), corresponding to the production of opal that has a delta (super 30) Si value 3.8 ppm+ or -0.8 ppm more negative than seawater silicic acid and a fractionation factor (alpha ) of 0.9964. This is three times the fractionation observed during opal formation by marine diatoms and terrestrial plants and is the largest fractionation of silicon isotopes observed for any natural process on Earth. The delta (super 30) Si values of sponge spicules across the Eocene-Oligocene boundary at Ocean Drilling Program Site 689 on Maud Rise range from -1.1 ppm to -3.0 ppm, overlapping the range observed for sponges growing in modern seawater.
Language:
English
Genre:
Serial
Rights:
URL:
Coverage: Geographic coordinates: North:-64.3100 West:3.0559 East:
3.0600 South:-64.3101
Keywords: Stratigraphy; Isotope geochemistry; Anomalinidae; Antarctic Ocean; biochemistry; biogenic processes; biomineralization; Cassidulinacea; Cenozoic; Cibicidoides; cores; deep-sea environment; Demospongea; ecology; Eocene; Foraminifera; framework silicates; geochemistry; Hexactinellida; Invertebrata; isotope fractionation; isotopes; Leg 113; lower Oligocene; marine environment; marine sediments; Maud Rise; microfossils; modern; modern analogs; Ocean Drilling Program; ODP Site 689; Oligocene; opal; paleo-oceanography; paleoecology; Paleogene; Porifera; Protista; reconstruction; Rotaliina; sediments; Si-30; silica minerals; silicates; silicon; Southern Ocean; spicules; stable isotopes; Tertiary; upper Eocene; Weddell Sea;
.