Magnetostratigraphy of sediments from Lake El'gygytgyn ICDP Site 5011-1: paleomagnetic age constraints for the longest paleoclimate record from the continental Arctic

Abstract

Paleomagnetic measurements were performed on sediments drilled from ICDP Site 5011-1 in Lake El'gygytgyn (67°30' N, 172°05' E) located in Far East Russian Arctic. The lake fills partly a crater formed by a meteorite impact 3.58 ± 0.04 Ma ago. Sediments from three parallel cores (5011-1A, 5011-1B and 5011-1C), recovered from the middle part of the lake, yielded a total of 355 m of sediment. Sediments are characterized by variable lithology, where intervals of homogenous and laminated sediments alternate, and mass movement deposits of variable thickness occur frequently along the sediment profile. Mineral magnetic investigation made on sediments enclosed in core catchers suggests that magnetic carrier in these sediments is partly maghemitized Ti-rich pseudo-single domain magnetite. Its detrital origin could be shown by mineral magnetic measurements and SEM-EDS analyses performed on mini-sized cylindrical rock samples, polished rock sections, creek sediments and magnetic extracts prepared from them. The intensity of the natural remanent magnetization (NRM) in the sediments is mainly high with a range from about 1 to 1000 mA m⁻¹. Most of the sediments carry a stable magnetization component interpreted as primary depositional remanent magnetization. Characteristic inclination data show alternating intervals of steep positive and negative inclinations that were used to assign magnetic polarity to the lake sediment profile. This was a rather straightforward procedure owing to the mainly high quality of data. The Matuyama/Gauss (2.608 Ma) and Brunhes/Matuyama (0.780 Ma) reversals were recognized in the sediments. Furthermore, during the Gauss chron the Mammoth and Kaena reversed subchrons, and during the Matuyama, the Olduvai and Jaramillo normal subchrons, as well as the Réunion and Cobb Mountain cryptochrons were identified. Sediment deposition rate is highest at the base of the sequence laid down in the beginning of Gauss chron, when deposition rate is approximately 44 cm kyr⁻¹. Sediment deposition decelerates upcore and it is an order of magnitude lower during the Brunhes chron when compared to that in early the Gauss chron. Decrease in sediment deposition in late Pliocene probably relates to atmospheric and oceanic reorganization heralding the onset of Quaternary climate change. The high-quality magnetostratigraphy reconstructed from Lake El'gygytgyn sediments provides 12 tie-points to pin down the age of the longest paleoclimate record from the continental Arctic

Chronology of Lake El'gygytgyn sediments – a combined magnetostratigraphic, palaeoclimatic and orbital tuning study based on multi-parameter analyses

“…Also turbidites, although representing short depositional events on a geological timescale, should record a polarity if not an accurate palaeomagnetic direction at least in their upper fine-grained section. Therefore, in intervals close to reversals, the directional data of rejected intervals, such as the onset of the Olduvai subchron and reversals within the Gauss chron (see Haltia and Nowaczyk, 2013), were also taken into consideration when determining the polarity and localization of the major reversals.…”

“…Determination of the inclination of characteristic remanent magnetization (ChRM), which provides the polarity interpretation, is based on principle component analysis (Kirschvink, 1980) of results from stepwise and complete alternating field demagnetisation of all material. More detailed information on sampling strategy, data acquisition techniques, and methods of processing are given by Haltia and Nowaczyk (2013).…”

“…Fixed age tie points for the ICDP Site 5011-1 composite record are provided by magnetostratigraphic investigation of sediments from this site by Haltia and Nowaczyk (2013). Ages for the documented major reversals were mainly assigned according to Lisiecki and Raymo (2005) magnetostratigraphy, a synchronous tuning of nine additional data sets was performed using an interactive wiggle matching software.…”

Multivariate statistic and time series analyses of grain-size data in Quaternary sediments of Lake El'gygytgyn, NE Russia

“…Detailed descriptions about the lithostratigraphy, MMD's, and the creation of the composite profile are given by Melles et al (2012), , and by Nowaczyk et al (2013) and Wennrich et al (2013b), respectively. The age model of the Lake El'gygytgyn sediment sequence is primarily based on magnetostratigraphic data (Haltia and Nowaczyk, 2013). It is further improved by tuning of sediment proxies (including grain-size data) to the global marine benthic isotope stack of Lisiecki and Raymo (2005, LR04) and to local insolation patterns inferred from orbital parameters according to Laskar et al (2004), Melles et al (2012) and Nowaczyk et al (2013).…”

Volcanic ash layers in Lake El'gygytgyn: eight new regionally significant chronostratigraphic markers for western Beringia

“…In the Holocene, more than 37 large volcanic centers and hundreds of monogenetic vents were active in Kamchatka and about 48 volcanoes are known from the Kurile Islands (Gorshkov, 1970;Siebert and Simkin, 2002;Ponomareva et al, 2007). On the Kurile Islands, the eruption history has been reviewed (Ostapenko et al, 1967;Gorshkov, 1970), although the research mainly focused on recent explosive eruptions (e.g., Nakagawa et al, 2002;Belousov et al, 2003;Hasegawa et al, 2012). In Kamchatka, where many explosive eruptions resulted in widespread dispersal of tephra-fall deposits, the Holocene eruptions and their sequences are well known (Braitseva et al, 1987(Braitseva et al, , 1995(Braitseva et al, , 1997(Braitseva et al, , 1998Kir'yanov et al, 1990;Bazanova and Pevzner, 2001;Gusev et al, 2003;Ponomareva et al, 2004Ponomareva et al, , 2007Kyle et al, 2011).…”