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Abstract <p>Lake Gryazevoe formed at the end of the Late Pleistocene, about 25 ka cal BP. It accumulated 780&#xa0;cm of sediments. Petromagnetic characteristics reflect the sedimentation conditions, governed primarily by climate. During the Late Pleistocene, terrigenous accumulation dominated in the basin. The composition of magnetic minerals and petromagnetic characteristics are similar in slope and lacustrine sediments. Magnetic minerals are represented mainly by titanomagnetites. Late Pleistocene sediments are characterized by relatively high magnetic susceptibility (MS), saturation magnetization (<i>Js</i>), and remanent saturation magnetization (Jrs). A noticeable change in sedimentation conditions associated with climate change occurred at the Pleistocene–Holocene boundary in the period from 12.7 to 11.3 ka cal BP. Bioproductivity in the lake increased. Due to the dilution of detrital material with organic matter and biogenic silica, the MS, <i>Js</i>, and <i>Jrs</i> values in Holocene sediments are low. The Early Holocene was dominated by chemogenic accumulation of highly coercive iron-bearing minerals, presumably lepidocrocite. Holocene sediments are characterized by the formation of authigenic framboidal pyrite. Magnetic iron sulfides with a greigite–pyrrhotite composition are noted in the transition layers from the Pleistocene to the Holocene. Cold climatic conditions were established in the Middle Holocene in the range of 4.7–6.9 ka cal BP. The sediments of this interval are characterized by increased MS, <i>Js</i>, and <i>Jrs</i> values and a smaller proportion of the paramagnetic component. Late&#xa0;Pleistocene deposits contain a record of paleosecular variations in the geomagnetic field.</p>

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Changes in Petromagnetic Characteristics in Late Pleistocene–Holocene Sediments of Glacial Lake Gryazevoe, Upper Kolyma

  • 期刊论文

  • 发表日期：

    2025年2月1日

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  • P. S. Minyuk,
  • D. K. Pozhidaeva,
  • S. S. Burnatny

摘要

Abstract

Lake Gryazevoe formed at the end of the Late Pleistocene, about 25 ka cal BP. It accumulated 780 cm of sediments. Petromagnetic characteristics reflect the sedimentation conditions, governed primarily by climate. During the Late Pleistocene, terrigenous accumulation dominated in the basin. The composition of magnetic minerals and petromagnetic characteristics are similar in slope and lacustrine sediments. Magnetic minerals are represented mainly by titanomagnetites. Late Pleistocene sediments are characterized by relatively high magnetic susceptibility (MS), saturation magnetization (Js), and remanent saturation magnetization (Jrs). A noticeable change in sedimentation conditions associated with climate change occurred at the Pleistocene–Holocene boundary in the period from 12.7 to 11.3 ka cal BP. Bioproductivity in the lake increased. Due to the dilution of detrital material with organic matter and biogenic silica, the MS, Js, and Jrs values in Holocene sediments are low. The Early Holocene was dominated by chemogenic accumulation of highly coercive iron-bearing minerals, presumably lepidocrocite. Holocene sediments are characterized by the formation of authigenic framboidal pyrite. Magnetic iron sulfides with a greigite–pyrrhotite composition are noted in the transition layers from the Pleistocene to the Holocene. Cold climatic conditions were established in the Middle Holocene in the range of 4.7–6.9 ka cal BP. The sediments of this interval are characterized by increased MS, Js, and Jrs values and a smaller proportion of the paramagnetic component. Late Pleistocene deposits contain a record of paleosecular variations in the geomagnetic field.