The Lake El’gygytgyn Scientific Drilling Project – Conquering Arctic Challenges through Continental Drilling

Abstract

Between October 2008 and May 2009, the International Continental Scientific Drilling Program (ICDP) co-sponsored a campaign at Lake El´gygytgyn, located in a 3.6-Ma-old meteorite impact crater in northeastern Siberia. Drilling targets included three holes in the center of the 170-m-deep lake, utilizing the lake ice cover as a drilling platform, plus one hole close to the shore in the western lake catchment. At the lake's center. the entire 315-m-thick lake sediment succession was penetrated. The sediments lack any hiatuses (i.e., no evidence of basin glaciation or desiccation), and their composition reflects the regional climatic and environmental history with great sensitivity. Hence, the record provides the first comprehensive and widely timecontinuous insights into the evolution of the terrestrial Arctic since mid-Pliocene times. This is particularly true for the lowermost 40 meters and uppermost 150 meters of the sequence, which were drilled with almost 100% recovery and likely reflect the initial lake stage during the Pliocene and the last ~2.9 Ma, respectively. Nearly 200 meters of underlying rock were also recovered; these cores consist of an almost complete section of the various types of impact breccias including broken and fractured volcanic basement rocks and associated melt clasts. The investigation of this core sequence promises new information concerning the El´gygytgyn impact event, including the composition and nature of the meteorite, the energy released, and the shock behavior of the volcanic basement rocks. Complementary information on the regional environmental history, including the permafrost history and lake-level fluctuations, is being developed from a 142-m-long drill core recovered from the permafrost deposits in the lake catchment. This core consists of gravelly and sandy alluvial fan deposits in ice-rich permafrost, presumably comprising a discontinuous record of both Quaternary and Pliocene deposits.

Late Pliocene and Early Pleistocene vegetation history of northeastern Russian Arctic inferred from the Lake El'gygytgyn pollen record

“…The upper boundary of the warm interval coincides rather well with the paleomagnetic Gauss-Matuyama boundary (Melles et al, 2011(Melles et al, , 2012Haltia and Nowaczyk, 2014;Nowaczyk et al, 2013). Thus, vegetation changes showing a transition from interglacial environmental conditions to glacial ones are reflected rather well at the PliocenePleistocene (MIS 104/MIS 103) boundary.…”

“…Within the scope of the El'gygytgyn Drilling Project of the International Continental Scientific Drilling Program (ICDP), three holes were drilled in the center of the lake (Fig. 2) between March and May 2009, penetrating about 318 m of lake sediments and 200 m into the underlying impact rocks (Melles et al, 2011(Melles et al, , 2012.…”

Vegetation history of central Chukotka deduced from permafrost paleoenvironmental records of the El'gygytgyn Impact Crater

“…1). This 141.5 m long core was recovered during a drilling campaign in winter 2008 within the framework of the international ICDP funded project "El'gygytgyn Drilling Project" (Melles et al, 2011). The main objective of the coring was to extend the permafrost record back in time in order to better understand the interaction between catchment processes and lake sedimentation.…”

Preliminary estimation of Lake El'gygytgyn water balance and sediment income

“…In the winter season of [2008][2009], deep drilling of Lake El'gygytgyn recovered long cores embracing both the entire lacustrine sediment sequence from the center of the basin (318 m) and a companion core into permafrost from outside the talik surrounding the lake (141.5 m, Melles et al, 2011). These cores now provide the science community with the longest terrestrial paleoenvironmental record from the Arctic, starting in the warm mid-Pliocene (Melles et al, 2012;Brigham-Grette et al, 2013).…”