![Deconstructing Terminations I and II: revisiting the glacioeustatic paradigm based on deep-water temperature estimates [An article from: Quaternary Science Reviews]](https://www.ebooknetworking.net/books/B00/0PD/bigB000PDT99K.jpg)
Deconstructing Terminations I and II: revisiting the glacioeustatic paradigm based on deep-water temperature estimates [An article from: Quaternary Science Reviews]
Book Details
Author(s)L.C. Skinner, N.J. Shackleton
PublisherElsevier
ISBN / ASINB000PDT99K
ISBN-13978B000PDT996
MarketplaceFrance 🇫🇷
Description
This digital document is a journal article from Quaternary Science Reviews, published by Elsevier in 2006. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.
Description:
Benthic and planktonic oxygen isotope (@d^1^8O"c"c) and Mg/Ca analyses in two cores from the Northeast Atlantic have permitted the reconstruction of surface- and deep-water temperature (T"d"w) and @d^1^8O (@d^1^8O"w) variations across the last two deglaciations. These records allow the timing of de-glacial melt-water pulses reaching the Northeast Atlantic to be compared with the evolution of local deep-water T"d"w-@d^1^8O"w conditions. Although each glacial termination is unique in detail, a similar pattern of hydrographic change is reconstructed for both deglaciations, with the first major decrease in deep-water @d^1^8O"w (due to sea-level and/or purely local deep-water change) occurring in parallel with the onset of intensely cold glacial surface-water temperatures, and prior to a 'terminal' ice-rafting and melt-water event. The evolution of deep-water across both de-glaciations involved two transient incursions of cold, low-@d^1^8O water into the deep Northeast Atlantic, the second of which was particularly pronounced each time. These pulses of cold deep-water are interpreted to reflect the incursion of water directly analogous to modern Antarctic Bottom Water (AABW), and containing a significant component of brine rejected during sea-ice formation. The results presented here show that the same type of transient changes in deep-water circulation that occurred across Termination I also occurred across Termination II, and that as a result of these deep-ocean changes, the timing of each benthic @d^1^8O 'termination' cannot precisely reflect the timing of de-glacial sea-level change, as many palaeoceanographic interpretations (and some controversies) are prone to assume. Such 'imprecision' (in timing especially) may well extend to marine isotope stage (MIS) boundaries in general, as a principle of hydrographic variability and its expression in the geological record.
Description:
Benthic and planktonic oxygen isotope (@d^1^8O"c"c) and Mg/Ca analyses in two cores from the Northeast Atlantic have permitted the reconstruction of surface- and deep-water temperature (T"d"w) and @d^1^8O (@d^1^8O"w) variations across the last two deglaciations. These records allow the timing of de-glacial melt-water pulses reaching the Northeast Atlantic to be compared with the evolution of local deep-water T"d"w-@d^1^8O"w conditions. Although each glacial termination is unique in detail, a similar pattern of hydrographic change is reconstructed for both deglaciations, with the first major decrease in deep-water @d^1^8O"w (due to sea-level and/or purely local deep-water change) occurring in parallel with the onset of intensely cold glacial surface-water temperatures, and prior to a 'terminal' ice-rafting and melt-water event. The evolution of deep-water across both de-glaciations involved two transient incursions of cold, low-@d^1^8O water into the deep Northeast Atlantic, the second of which was particularly pronounced each time. These pulses of cold deep-water are interpreted to reflect the incursion of water directly analogous to modern Antarctic Bottom Water (AABW), and containing a significant component of brine rejected during sea-ice formation. The results presented here show that the same type of transient changes in deep-water circulation that occurred across Termination I also occurred across Termination II, and that as a result of these deep-ocean changes, the timing of each benthic @d^1^8O 'termination' cannot precisely reflect the timing of de-glacial sea-level change, as many palaeoceanographic interpretations (and some controversies) are prone to assume. Such 'imprecision' (in timing especially) may well extend to marine isotope stage (MIS) boundaries in general, as a principle of hydrographic variability and its expression in the geological record.
