The utility of stable isotopic signatures in coral skeletons

1996 ◽  
Vol 1 ◽  
pp. 249-291 ◽  
Author(s):  
Peter K. Swart ◽  
Jim J. Leder
Keyword(s):  
Isotopic Composition ◽  
Dissolved Inorganic Carbon ◽  
Carbon Isotopic Composition ◽  
Oxygen Isotopic Composition ◽  
Stable Carbon ◽  
Carbon And Oxygen Isotopes ◽  
Coral Skeletons ◽  
Carbon And Oxygen Isotope ◽  
Oxygen Isotopic ◽  
Zooxanthellate Corals

There is a fundamental ecologic differentiation between zooxanthellate and non-zooxanthellate corals. This paper reviews factors which govern the stable carbon and oxygen isotopic composition of these groups of corals. Although the stable carbon and oxygen isotope compositions of coral skeletons are strongly influenced by environmental and physiological factors, the precise mechanisms remain a matter of debate. In particular the oxygen isotopic composition is known to be governed by the temperature and the oxygen isotopic composition of the water and perhaps also by kinetic factors. In contrast the carbon isotopic composition is controlled by a combination of photosynthesis, respiration, autotrophy, heterotrophy, and the isotopic composition of dissolved inorganic carbon. Using a combination of carbon and oxygen isotopes it is possible to distinguish zooxanthellate from non-zooxanthellate corals.

U/Th age constraints on the absence of ice in the central Inn Valley (eastern Alps, Austria) during Marine Isotope Stages 5c to 5a

2006 ◽  
Vol 66 (1) ◽  
pp. 167-175 ◽  
Author(s):  
Christoph Spötl ◽  
Augusto Mangini
Keyword(s):  
Isotopic Composition ◽  
Carbon Isotopic Composition ◽  
Ice Cores ◽  
Eastern Alps ◽  
Oxygen Isotopic Composition ◽  
Low Carbon ◽  
Carbon Isotopic ◽  
Oxygen Isotopic ◽  
Temperature Records ◽  
Marine Isotope Stage 5

AbstractCalcitic flowstones are present in fractures of a Pleistocene breccia near Innsbruck, Austria, and record periods of carbonate precipitation in the unsaturated zone between 101,500 ± 1500 and 70,300 ± 1800 yr, constrained by U-series disequilibrium dates. The occurrence of these speleothems, their low carbon isotopic composition, and the lack of infiltrated siliciclastic material demonstrate that the central Inn valley – which harbored one of the most extensive valley glaciers during the last glacial maximum – was ice-free during Marine Isotope Stages 5c to 5a. Climatically warm periods are separated by distinct drops in the oxygen isotopic composition of the speleothem calcite, attributed to strong and possibly seasonally biased atmospheric cooling. During these intervening stadials, which mirror those identified in the Greenland ice cores and marine sea-surface temperature records, calcite deposition apparently came to a halt, but the Inn Valley remained ice-free. The youngest calcite layer formed between ∼74,000 and ∼70,000 yr and places a maximum age limit on the likely expansion of alpine glaciers during the Marine Isotope Stage 5/4 transition, consistent with other speleothem records.

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