Andrew Marc Solod Festival of Science 2001 Poster Presentation

Andrew Marc Solod

Faculty Advisor Dr. J. Mark Erickson, Department of Geology

St Lawrence University Festival of Science 2001 - Poster Presentation

Recognition of the Younger Dryas Cold Episode at Glovers Pond Northwestern N.J.

The last de-glaciation period between 20,000-8,000 B.P. was punctuated by rapid global and regional climate fluctuations. Major climatic episodes of the later Quaternary include from oldest to present the Older Dryas, Bolling, re-emergence of Older Dryas, Allerod, Younger Dryas, and Preboreal. The onset of the Younger Dryas cooling episode is calibrated to 12, 650 B.P.

Glovers Pond is a small temperate lake in northwestern New Jersey located in close proximity to the southern most terminus of the Wisconsin Glacial maximum providing a nearly complete record of lacustrine sediment deposition from around 17,500 B.P. to the present (Erickson 1968). Erickson and Carpenter, (1998) have demonstrated the presence of the Younger Dryas at Glovers Pond through isotope analysis. The objective of my thesis is to determine the usefullness of fossil moss mites (Arthropoda: Oribatida) as paleoclimatic indicators for determining the Younger Dryas. Erickson (1997) has demonstrated the value of fossil mites as paleoecological and paleoclimatological indicators, but research has not been conducted linking population and species densities to large Quaternary climatic fluctuations.

The mites sampled for my thesis were collected during the summer of 2000 in one 9.3 meter core divided in 5 two-meter core barrels. Sections 3 and 4 were cut into 1 cm intervals, weighed and picked for mites, from a starting depth of 635 cm below the surface to a height of 515 cm below the surface. 26 different genera have been identified from the core, Hydrozetes sp., Hetrozetes sp. Hetrozetes aquaticus, Trimalaconothrus maior, Tegeocranellus sp., Limnozetes sp., Suctobelbella sp., oripodid, Achipteria sp, schelorabaid, Scheloribates sp., Xylobates sp., galumnid, Podoribates sp., belbid/oppiid, Podoribates sp., Phauloppia sp., Oripoda elongata, Cepheus? sp., Cultrobates quadricuspidatus, Pirnodus? sp., pelopid, Pleodamaeus sp., Oribatula sp., Scapheremaeus sp., and Tectocepheus velatus.

Taphonomic studies were conducted during the mounting process on a scale of 1-5, 1 being inflated with all important distinguishing features preserved and 5 partially consumed. Populations were divided into terrestrial, Limnozetes, and Hydrozetes. Several marked population changes were C¹⁴ dated at depths of 515 cm, 556cm, 581cm, an AMS date. The results gave an AMS age calibrated to 12,745 B.P., the non AMS dates were age revered possibly due to lake level fluctuations and erosion.

Genera and population concentrations define the core by four zones representing large climatic transitions. Taphonomic preservation graphed against population densities has demonstrated marginal increases in preservation quality synchronous with higher population concentrations. The Preboreal, Younger Dryas, and Older Dryas?, are defined by higher population count, increased genera diversity, and increased taphonomic preservation, compared against the Allerod episode. Dominant mite genera of the Younger Dryas include belbid/oppiid, Scheloribates sp., schelorabatid, and Oripoda elongata, as well as marked population increases of Limnozetes sp. and Hydrozetes sp.