The North American Varve Chronology Today
The North American Varve Chronology (NAVC) is a correction and consolidation of the old New England Varve chronology (NEVC) into a single varve sequence. The NAVC has a new numbering system (AM varve years) to accomplish these changes. Shown on the profiles below are all the varve sections that were used to compile Antevs (1922, 1928) original NEVC as well as new sections all translated to AM varve years. The approximate geographic locations and relative ages of compiled varve sections in the NAVC are shown on the map below as a guide to the regional occurrence of different parts of the chronology. In this compilation the NAVC is a continuous 5659-yr sequence (AM 2700-8358). The map also serves as a location map for the detailed time-distance plots of all of the known varve sections that are a part of the NAVC or have been matched to it. The plots show the time spans of individual varve sections plotted along the axis of the various valleys in the direction of ice recession. By placing your cursor in the red boxes you can view the detailed plots for each valley section including separate areas in: Connecticut, Massachusetts, southern Vt./N.H., central Vt./N.H., and northern Vt./N.H. in the Connecticut Valley. Also shown are sections in the Hudson Valley near Newburgh and Catskill, NY, the Merrimack Valley, and the Winooski Valley. The Ashuelot Valley near Keene, NH has not been plotted because it is represented by only one section.
- Data files for the NAVC (Antevs’ original normal curves translated to AM years) are available for download through NAVC Downloads
- Data files for new varve sections that have been matched to the NAVC as well as many other varve records in the northeastern U.S. and adjacent Canada are available for download through this link.
- A table and computer program for converting between NEVC and NAVC years are also available for download at NAVC/NEVC Conversion
Use the map to locate the varve stratigraphy for a particular area by clicking in areas outlined with thin red lines. You may click on a tab heading to the right of the map to open the corresponding varve record as well. This page is best viewed at 1024x768 pixels and above.
Map and Section Key
- All numbered sections in dark blue on the diagrams are the original sections measured by Antevs to compile the NEVC that have been corrected and translated to the NAVC. Data for these sections are available at NAVC Data and Downloads.
- All sections in red have been matched to the NAVC by later workers. Red section sites in the Merrimack Valley are in Ridge and others (2001). Sites in the Connecticut Valley without references were compiled at Tufts University and have not yet been published. Data for these sections are available at Northeastern U.S. Data and Downloads.
- Pink circles are sections where the bottom of the measured varves rests on till, bedrock, or ice-proximal sand and gravel, i.e. basal varves.
- Light blue squares mark sections where the bottom measured varves are thick and sandy ice-proximal varves interpreted to be deposited within a century (and usually within a decade or two) of deglaciation.
- The dashed line across the bottom of the sections represents the interpreted maximum age of varves resting on the deglaciated surface or the age of deglaciation along the profile line.
- Also shown in the Hudson Valley is the position of the flood events that were originally measured by De Geer (Antevs, 1922) as separate varves.
References
- Antevs, E., 1922, The Recession of the Last Ice Sheet in New England: American Geographical Society Research Series, no. 11, 120 p.
- Antevs, E., 1928, The Last Glaciation with Special Reference to the Ice Sheet in North America: American Geographical Society Research Series, no. 17, 292 p.
- Levy, L.B., 1998, Interpreting the carbonate concretions of glacial Lake Hitchcock: Unpublished B.A. Thesis, Mount Holyoke College, Mount Holyoke, Massachusetts, 126 p.
- Lougee, R.J., 1935b. Time measurements of an ice readvance at Littleton, N.H. Proceedings of the National Academy of Sciences 21, 36-41.
- Ridge, J.C., Larsen, F.D., 1990, Re-evaluation of Antevs’ New England Varve Chronology and new radiocarbon dates of sediments from glacial Lake Hitchcock: Geological Society of America Bulletin, v. 102, p. 889-899.
- Ridge, J.C., Toll, N.J., 1999, Are late-glacial climate oscillations recorded in varves of the upper Connecticut Valley, northeastern United States?: Geologiska Foreningens i Stockholm Förhandlingar 121(3), p. 187-193.
- Ridge, J.C., Thompson, W.B., Brochu, M., Brown, S., Fowler, B., 1996, Glacial geology of the upper Connecticut Valley in the vicinity of the lower Ammonoosuc and Passumpsic Valleys of New Hampshire and Vermont, in Van Baalen, M.R. (Ed.), Guidebook to Field Trips in Northern New Hampshire and Adjacent Regions of Maine and Vermont: 88th Annual Meeting, New England Intercollegiate Geological Conference, Harvard University, Cambridge, Massachusetts, p. 309-340.
- Ridge, J.C., Canwell, B.A., Kelly, M.A., and Kelley, S.Z., 2001, An atmospheric 14C chronology for Late Wisconsinan deglaciation and sea level change in eastern New England using varve and paleomagnetic records: in Weddle, T. and Retelle, M., Deglacial History and Relative Sea-level Changes, Northern New England and Adjacent Canada: Geological Society of America Special Paper no. 351, p. 171-189.
- Rittenour, T.M., 1999, Drainage history of glacial Lake Hitchcock, northeastern USA: Unpublished M.S. Thesis, Univ. of Massachusetts, Amherst, 179 p.
- Stone, J.R., Stone, B.D., DiGiacomo-Cohen, M.L., Lewis, R.S., Ridge, J.C., and Benner, J.S., 2005, The new Quaternary geologic map of Connecticut and Long Island Sound Basin; Part 2 – Illustrated by a fieldtrip in the Connecticut River Valley, in Skinner, B.J. and Philpotts, A.R., eds., Guidebook for Field Trips in Connecticut: 97th Annual Meeting, New England Intercollegiate Geological Conference, Yale University, New Haven, Connecticut, Trip B2, p. 131-159.
- Thomas, G.M., 1984, A comparison of the paleomagnetic character of some varves and tills from the Connecticut Valley: Unpublished M.S. Thesis, Univ. of Massachusetts, Amherst, 136 p.
- Wilson, B.R., 2000, A chronology and environmental interpretation of glacial to non-glacial lacustrine varves in the Passumpsic Valley, Barnet, Vermont: Unpublished B.S. Thesis, Tufts University, Medford, Massachusetts, 83 p.
