Development of chronological tools

Precise correlation between high precision palaeoclimate archives over the last 60,000 years is critical to gain a better understanding of the exact timing and, hence, mechanisms and impacts of past climate change. The abrupt climatic changes in this time-frame occur at millennial to centennial scales and developing and integrating independent chronologies for proxy records with this level of resolution is a core goal of INTIMATE. The INTIMATE approach is the key here, as only by using independently derived chronologies can we assess the reliability of comparisons between records (e.g. Blockley et al., 2012). INTIMATE scientists have been at the forefront of developing key protocols for advancing this research over a number of years (e.g. Brauer et al., 2014), and have pioneered methods for high precision dating of ice core, marine and terrestrial records (e.g. Rasmussen et al., 2008; Bronk Ramsey et al., 2008; Davies et al., 2012; Kaiser et al., 2012; Reimer et al., 2013).

Collaboration between scientists within INTIMATE has led to the promotion of an integrative approach to chronology-building, using multiple dating methods wherever possible. The flagship INTIMATE event stratigraphy, based upon the climate events recorded in the Greenland ice cores, provides a precisely dated archive to which regional records can be compared (e.g. Lowe et al., 2008; Blockley et al., 2012; Rasmussen et al., 2014). This is now augmented by the addition of tephra isochrons (Blockley et al., 2014), by correlation with European varve lake sequences (Lane et al., 2013), and via new models for direct transfer of records onto the IntCal13 radiocarbon timescale (Bronk Ramsey et al., 2014; Muscheler et al., 2014).

A new phase of chronological research for INTIMATE will see further methodological developments and applications leading to improved integration of records from Europe, the North Atlantic and extending to other regions of the globe (e.g. Pedro et al., 2011; Nakagawa et al., 2012; Veres et al., 2013). The value of incorporating a wider range of dating methods (e.g. U-series, luminescence, cosmogenic nuclide dating) into INTIMATE research have been discussed at recent workshops and advances in the robust correlation of, for example, speleothem, loess and complex marine systems are on the horizon (Brauer et al., 2014).


Blockley, S.P.E., Lane, C.S., Hardiman, M., Rasmussen, S.O., Seierstad, I.K., Steffensen, J.P., Svensson, A., Lotter, A.F., Turney, C.S.M., Bronk Ramsey, C., 2012. Synchronisation of palaeoenvironmental records over the last 60,000 years, and an extended INTIMATE 1 event stratigraphy to 48,000 b2k. Quaternary Science Reviews 36, 2.
Brauer, A., Hajdas, I., Blockley, S.P., Ramsey, C.B., Christl, M., Ivy-Ochs, S., Moseley, G.E., Nowaczyk, N.N., Rasmussen, S.O., Roberts, H.M., 2014. The importance of independent chronology in integrating records of past climate change for the 60–8 ka INTIMATE time interval. Quaternary Science Reviews.
Davies, S.M., Abbott, P.M., Pearce, N.J.G., Wastegård, S., Blockley, S.P.E., 2012. Integrating the INTIMATE records using tephrochronology: Rising to the challenge. Quaternary Science Reviews 36, 11.
Kaiser, K.F., Friedrich, M., Miramont, C., Kromer, B., Sgier, M., Schaub, M., Boeren, I., Remmele, S., Talamo, S., Guibal, F., 2012. Challenging process to make the Lateglacial tree-ring chronologies from Europe absolute–an inventory. Quaternary Science Reviews 36, 78-90.
Lane, C.S., Brauer, A., Blockley, S.P.E., Dulski, P., 2013. Volcanic ash reveals time-transgressive abrupt climate change during the Younger Dryas. Geology 41, 1251-1254.
Lowe, J.J., Rasmussen, S.O., Björck, S., Hoek, W.Z., Steffensen, J.P., Walker, M.J.C., Yu, Z.C., 2008. Synchronisation of palaeoenvironmental events in the North Atlantic region during the Last Termination: a revised protocol recommended by the INTIMATE group. Quaternary Science Reviews 27, 6.
Muscheler, R., Adolphi, F., Knudsen, M.F., 2014. Assessing the differences between the IntCal and Greenland ice-core time scales for the last 14,000 years via the common cosmogenic radionuclide variations. Quaternary Science Reviews.
Nakagawa, T., Gotanda, K., Haraguchi, T., Danhara, T., Yonenobu, H., Brauer, A., Yokoyama, Y., Tada, R., Takemura, K., Staff, R.A., 2012. SG06, a fully continuous and varved sediment core from Lake Suigetsu, Japan: stratigraphy and potential for improving the radiocarbon calibration model and understanding of late Quaternary climate changes. Quaternary Science Reviews 36, 164-176.
Pedro, J.B., Rasmussen, S.O., van Ommen, T.D., 2012. Tightened constraints on the time-lag between Antarctic temperature and CO 2 during the last deglaciation. Climate of the Past 8, 1213-1221.
Ramsey, C.B., 2008. Deposition models for chronological records. Quaternary Science Reviews 27, 42-60.
Ramsey, C.B., Albert, P., Blockley, S., Hardiman, M., Lane, C., Macleod, A., Matthews, I.P., Muscheler, R., Palmer, A., Staff, R.A., 2014. Integrating timescales with time-transfer functions: a practical approach for an INTIMATE database. Quaternary Science Reviews.