LOSS-ON-IGNITION AND HUMIFICATION INDEX OF PEAT DEPOSITS NEAR PENOBSCOT, MAINE: IMPLICATIONS FOR HOLOCENE CLIMATE

The purpose of this study was to reconstruct a Holocene climate proxy record from peat deposits near Penobscot, Maine. A 129 cm core (EB-09-01) was collected from an abandoned peat mine using a Russian Corer. The core was sub-sampled at approximately 4 cm intervals, with an increased sampling resolution when a distinct change in stratigraphy of the peat was visible. A radiocarbon date of a piece of wood at 118 cm is 5920±50 ¹⁴C yrs BP, indicating that every 10 cm of peat corresponds to approximately 500±50 years. In the laboratory, sedimentology analyses, including water content and loss-on-ignition (LOI), were preformed for each sub-sample of peat. A high value for LOI represents a high percentage of carbon in the peat, which is indicative of a period with high productivity and warm temperature. A low value for LOI represents a low percentage of carbon in the peat, which is interpreted as a period with a low level of productivity and cool temperature. Preliminary analysis of water content data shows an overall increase in water content with depth from 76% water content at the surface to 89% content in the lowest 40cm of the core, with some major and minor fluctuations throughout the core. Initial analysis of LOI reveals a similar trend to water content, with an LOI of 87% at the surface and a sharp increase with depth. LOI increases to about 98% at a depth of 20cm, and remains at that level throughout the remainder of the core with small variations. The degree of humification corresponds to the overall decomposition of the samples, providing a proxy for the precipitation during approximately the last 6000 years. Measurements of absorbance and percent light transmission are analyzed using a Spectronic 20 Genesys at 540 nm to determine the degree of humification. Humification analyses are currently in progress.