Publikationsdatum:
2015-03-26
Beschreibung:
Publication date: Available online 24 March 2015 Source: Quaternary Research Author(s): Lorita N. Mihindukulasooriya , Joseph D. Ortiz , David P. Pompeani , Byron A. Steinman , Mark B. Abbott Visible derivative spectroscopy (VDS) analysis of sediment from Cleland Lake, Southeastern British Columbia provides a reconstruction of paleolimnological productivity and hydrologic change during the past 14,000 calibrated 14 C years before present (cal yr BP). The first five principal components (PC) of the VDS data explain 97% of the variance in the VDS data set. Four PCs correlate with standard reflectance derivative spectra for diatom, dinoflagellate algae, and cyanophyte pigments that record ecological change, while two PCs are paleohydrologic indicators. Dinoflagellate algae are predominant from 11,600 to 8600 cal yr BP then decrease to low levels after ~ 8500 cal yr BP. PCs 3–5 represent variations in cyanophyte abundance and exhibit peaks from 14,000 to 11,600, 14,000 to 9500, and 6100 to 5400 cal yr BP, respectively. Conditions shifted toward favoring diatoms around 9400 and lasted until 170 cal yr BP. Higher dinoflagellate-related pigment concentrations suggest a lower lake level from 11,600 to 8600 cal yr BP, followed by higher water levels and wetter conditions after 8500 cal yr BP. We propose that drier conditions transitioning from the late glacial into the Holocene were caused by summer insolation-driven, non-linear feedbacks between the northern hemisphere subtropical high-pressure systems, vegetation, and soil moisture.
Print ISSN:
0033-5894
Digitale ISSN:
1096-0287
Thema:
Geographie
,
Geologie und Paläontologie
Permalink
