PALEOCLIMATE OBJECTIVE OF LAS

LAS can be used as a climate proxy in a variety of environments. It has the two crucial characteristics of such proxies: (1) rapid measurement speed, making determination of a high-resolution record practical, and (2) a clear conceptual link between climate process and instrument response, which can be readily validated through selected ground-truth measurements.

Our pilot studies have demonstrated that LAS can provide a rapid, reliable estimate of variations in relative abundance of several climatically sensitive sediment components. We have investigated detection of four such components.

  1. Calcite. The pelagic calcite mass accumulation rate (MAR), whether from foraminifers or nannofossils, reflects a combination of factors fostering accumulation (productivity of near-surface waters) and dissolution (calcite compensation depth).
  2. Opal. Pelagic opal MAR, whether from radiolarians or diatoms, is particularly sensitive to upwelling-induced supply of nutrients.
  3. Smectite vs. illite. Low-latitude pelagic deposition of these minerals may vary as wind patterns tap different source regions (Rea, 1994).

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