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

N R Nowaczyk,E M Haltia,C Meyer-Jacob,A Francke,V Wennrich,A A Andreev,M A Sauerbrey,H Vogel,A V Lozhkin,D Ulbricht,P Rosén

doi:10.5194/cp-9-2413-2013

Abstract

Abstract. A 318-metre-long sedimentary profile drilled by the International Continental Scientific Drilling Program (ICDP) at Site 5011-1 in Lake El'gygytgyn, Far East Russian Arctic, has been analysed for its sedimentologic response to global climate modes by chronostratigraphic methods. The 12 km wide lake is sited off-centre in an 18 km large crater that was created by the impact of a meteorite 3.58 Ma ago. Since then sediments have been continuously deposited. For establishing their chronology, major reversals of the earth's magnetic field provided initial tie points for the age model, confirming that the impact occurred in the earliest geomagnetic Gauss chron. Various stratigraphic parameters, reflecting redox conditions at the lake floor and climatic conditions in the catchment were tuned synchronously to Northern Hemisphere insolation variations and the marine oxygen isotope stack, respectively. Thus, a robust age model comprising more than 600 tie points could be defined. It could be shown that deposition of sediments in Lake El'gygytgyn occurred in concert with global climatic cycles. The upper ~160 m of sediments represent the past 3.3 Ma, equivalent to sedimentation rates of 4 to 5 cm ka−1, whereas the lower 160 m represent just the first 0.3 Ma after the impact, equivalent to sedimentation rates in the order of 45 cm ka−1. This study also provides orbitally tuned ages for a total of 8 tephras deposited in Lake El'gygytgyn.

Highlights

Lake El’gygytgyn in the Far East Russian Arctic (67.5◦ N, 172◦ E) with a diameter of 12 km is located off-centre in an 18 km wide impact crater formed 3.58 Ma ago (Layer, 2000)
The major reversals of the earth’s magnetic field, slumps, and other disturbances, such as folded sediments. as incorporated in the official geomagnetic polarity timescale. These intervals were discarded for the creation (GPTS, Ogg and Smith, 2004; Table 1), provide twelve 1st www.clim-past.net/9/2413/2013/
The only conclusion that can be drawn is that the older limit for the age of the impact can be set to 3.588 Ma, when adopting the LR04 timescale, or to 3.596 Ma when using the Ogg and Smith (2004) geomagnetic polarity times scales (GPTS)

Summary

Introduction

Lake El’gygytgyn in the Far East Russian Arctic (67.5◦ N, 172◦ E) with a diameter of 12 km is located off-centre in an 18 km wide impact crater formed 3.58 Ma ago (Layer, 2000). The bedrock in the crater catchment consists mainly of igneous rocks, lavas, tuffs, ignimbrites of rhyolites and dacites, rarely andesites and andesitic tuffs (Gurov and Koeberl, 2004), some of them with ages from 83.2 to 89.3 Ma (Layer, 2000) and 88 Ma (Kelley et al, 1999) They were emplaced during the Cretaceous normal polarity superchron (Ogg and Smith, 2004). Nowaczyk et al.: Chronology of Lake El’gygytgyn sediments

Methods

Results

Discussion

Conclusion