This article was downloaded by: [Frederick Vollmer] On: 02 July 2013, At: 13:34 Publisher: Taylor & Francis Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK GFF Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/sgff20 ANTEVS: a quantitative varve sequence cross- correlation technique with examples from the Northeastern USA John A. Rayburn a & Frederick W. Vollmer a a Department of Geological Science , State University of New York at New Paltz , New Paltz , NY , 12561 , USA E-mail: Published online: 01 Jul 2013. To cite this article: GFF (2013): ANTEVS: a quantitative varve sequence cross-correlation technique with examples from the Northeastern USA, GFF, DOI: 10.1080/11035897.2013.801924 To link to this article: http://dx.doi.org/10.1080/11035897.2013.801924 PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. 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VOLLMER Rayburn, J.A. & Vollmer, F.W., 2013: ANTEVS: a quantitative varve sequence cross-correlation technique with examples from the Northeastern USA. GFF, Vol. 00 (Pt. 1, ), pp. 1–11. q Geologiska Fo¨reningen. doi: http://dx.doi.org/10.1080/11035897.2013.801924. Abstract: Varve correlation by hand was successfully applied by Ernst Antevs to establish the New England Varve Chronology, which has since been updated to form the North American Varve Chronology (NAVC). Although these methodologies are successful, numerical techniques can assist in finding and evaluating correlations. A quantitative numerical method for varve correlation using time- series Fourier analysis and cross-correlation is proposed and implemented in the computer program ANTEVS (Automatic Numerical Time-series Evaluation of Varve Sequences). The technique is demonstrated by correlating several varve sequences in the northeastern USA. Tests on NAVC data from the Hudson and Connecticut River Valleys show strong positive local and regional cross- correlations, confirming the method’s validity. Guidelines for the evaluation of the correlation are determined by cross-testing NAVC sequences, suggesting minimum values for the cross-correlation statistic r, and z-score, a measure of its variation. Field relationships and careful examination of the data graphs and correlograms, however, must accompany numerical analysis. We then apply the method to previously uncorrelated sequences. A Champlain Valley varve sequence at Whallonsburg, NY, is compared with the NAVC, and to another Champlain Valley sequence at Keeseville, NY. No match is found with the NAVC, although none was expected as the sequences are of slightly different ages. A weak correlation is found between the two Champlain Valley sequences. This correlation is not significant and disagrees with the stratigraphic interpretation of the sites. We suggest that an overly strong local sedimentary signal at one of the sites masks the regional signal necessary for positive cross-correlation. Keywords: varve chronology; Fourier analysis; time-series; glacial; Laurentide; ice retreat. Department of Geological Science, State University of New York at New Paltz, New Paltz, NY 12561, USA; [email protected], [email protected] Manuscript received 29 October 2012. Revised manuscript accepted 30 April 2013. Downloaded by [Frederick Vollmer] at 13:34 02 July 2013 Introduction Antevs (1922) introduced North America to the Gerard De glacial Lake Hitchcock in the Lower Connecticut River Valley Geer method of varve chronology construction. Outcrops (Fig. 1) to New England (NE) varve year 3001. Through the were cleaned and smoothed and varve measurements were comparison of 21 individual curves, Antevs (1922) created a made from the bottom up and recorded directly on long strips 4400-year long chronology, although he was concerned about an of paper. Field measurements were then transformed into a apparent gap in his record from the area near Claremont, NH. graphical representation by plotting curves on paper with To account for the “Claremont Gap”, he arbitrarily added 249 lines set 5 mm apart. Matching of varve sequences from one years into his chronology which spanned NE varve years 3001– location to another was accomplished by sliding one graph 7400. Continued work in the region allowed Antevs (1928) to along another until a match was observed. Overlapping extend his chronology from varve years 2700–7750. Antevs’ sequences were merged to build a long chronology. Antevs chronology was a powerful tool in the study of regional (1922, 1928) demonstrated this technique very successfully deglacial history allowing correlations of ice margin position by constructing the New England Varve Chronology (NEVC) and estimations of ice margin retreat rates in an age before from lacustrine outcrops throughout the Connecticut River radiocarbon dating. Valley and surrounding areas. A resurgence of study on the NEVC by Ridge & Larsen Originally, the NEVC was constructed as a floating (1990), Rittenour (1999), Ridge (2004) and Balco et al. chronology. Not anchored in calendar years, but rather in (2009) among others has refined the NEVC and attempted to varve years, Antevs arbitrarily assigned his earliest varve from make it an absolute chronology by the use of radiocarbon, SGFF 801924—28/6/2013—ANANDAN.R—450588——Style GFF 2 Rayburn and Vollmer: Quantitative varve sequence cross-correlation GFF 00 (2013) Fig. 1. Location of large proglacial lakes in Quebec the northeastern USA (after Ridge et al. 2012). The NE and North American varve chronologies were primarily developed in glacial Lake Hitchcock (Connecticut River Vermont Valley). Antevs’ (1922) Sites 23 and 28 are 30 km apart and have a suggested overlap of 241 varves in the NAVC. A regionally Keeseville correlative varve set exists in glacial Lake Whallonsburgh Albany (Hudson River Valley). Glacial Lake Vermont began in the Champlain Lake Valley and extended into southern Quebec Maine and Ontario (Canada). We begin the LVVC Vermont with cores from Whallonsburg and (Fort Ann Phase) compare it with varves at Keeseville, New Lake York. Hitchcock New Hampshire Lake Albany NEVC 28 NEVC 23 Massachusetts New York Hartford Newburgh Connecticut Pennsylvania Rhode Island New Jersey paleomagnetic and cosmogenic-nuclide exposure dating Methods techniques. These efforts identified errors in the NEVC, including a significant miscount in the Hudson Valley varve Cores, counts and measurements section of glacial Lake Albany (Fig. 1) by Rittenour (1999), Two long (14.6 and 22.3 m) 6-cm diameter sediment cores were and bracketed the age of the chronology between 18 050 and taken at Whallonsburg, NY (Fig. 1) above the bank of the Downloaded by [Frederick Vollmer] at 13:34 02 July 2013 12 410 calendar years before present (cal. yr. BP) (Balco et al. Boquet River in proximity to a bank exposure of varved glacial 2009). The most recent effort (Ridge et al. 2012) closed the lacustrine silts and clays. The deeper of the two coring drives Claremont Gap and recalibrated the chronology creating the refused on what we assume to be glacial till, based on hammer new North American Varve Chronology (NAVC). This was seismic surveys near the core site. The cores were taken in 1.5- accomplished through improved sediment coring techniques m-long connected core tubes using a United States Geological and digital varve measurement procedures. The NAVC also Survey mobile drilling truck. There was a 1-m offset between begins at varve year 2700 but is a continuous 5659-year tube breaks in the two cores so that a complete and uninterrupted record, which incorporates a total of 54 radiocarbon dates for varve sequence could be constructed. The cores were split, age control (Ridge et al. 2012). described, photographed and subsampled for microfossil and Although varves from glacial Lake Albany in the Hudson geochemical analyses (Rayburn et al. 2011). Varves were Valley of New York State have successfully been incorporated counted by hand in the archived half and pins were inserted into into the NAVC, varves from glacial Lake Vermont in the the core to mark decadal intervals (Fig. 2). Carefully scaled Lake Champlain Valley to the north (Fig. 1) have not digital photographs were then taken and varve measurements to (Rayburn 2004). Even positively correlating varve sequences the nearest 0.1 cm were made on a computer display adjusted for within the Champlain basin has proven difficult (Rayburn higher contrast. Care was taken to measure each varve at or near 2004). We report here a new attempt through the the center of the photograph to avoid measurement error due to incorporation of improved coring and digital measurement photographic parallax. techniques similar to methods described by Ridge et al.