Послеледниковые изменения относительного уровня моря на полуострове Файлдс, остров Кинг Джордж (Западная Антарктика)

Analysis and integration of data obtained in our field and laboratory investigations of 2008–2012 together with results of previous paleogeographic studies were conducted to reveal parameters and factors of the post-glacial changes in the relative sea-level on the Fildes Peninsula and the King George Island. Results of dating of organic material taken from cross-sections of Quaternary deposits, data on morphology of marine landforms as well as on bottom sediments in lakes were used to construct a curve of changes in the relative sea-level.Our research has shown that the rapid rise of relative sea level in the area (since the beginning of the Holocene) decelerated about 8000 years BP, achieving its maximum about 7000 years BP. This was followed by the fall of relative sea-level (the land elevation) by 18–20  m in total, and it was characterized by relatively high rate of fall during periods of 6000– 5000 years BP, 4000–2500 years BP, and during the last 1500 years; the rate decreased in 5000–4000 years BP and 2500– 1600 years BP. The changes in relative sea level in this region were determined by the following factors: the eustatic component of the global changes in sea-level and, possibly, oscillations in the global sea level of another nature; local parameters of the Last glacial maximum; a course of the Peninsula deglaciation; regional physical characteristics of the Earth's crust and the mantle substances; local tectonic processes, including the isostatic rebound. Since the beginning of the Holocene up to about 7000 years BP, the main contribution to changes of the relative sea-level in this area was made by the global eustatic factor. The subsequent fall of the relative sea-level (elevation of the Peninsula surface) proceeded under condition of reduced role of the eustatic factor and predominance of other factors.Послеледниковые изменения относительного уровня моря на п-ове Файлдс (о. Кинг Джордж) установлены на основе анализа и интеграции результатов собственных и предшествующих палеогеографических исследований. Быстрый подъём относительного уровня моря (с начала голоцена) замедлился около 8000 лет назад (л.н.) с достижением около 7000 л.н. своего максимума. Скорости последовавшего затем падения уровня моря (поднятия суши) на 18–20 м уменьшались в периоды около 5000–4000 и 2500–1600  л.н. Выявленные изменения зависели преимущественно от эвстатического фактора примерно до 7000  л.н.; дальнейшие изменения в большей степени были обусловлены региональными параметрами оледенения последнего ледникового максимума, ходом дегляциации, региональными особенностями земной коры и мантийного вещества, локальными тектоническими процессами (включая гляциоизостазию)

Биогеохимия мерзлых толщ арктического побережья полуострова Гыдан

Biogeochemistry of permanently frozen deposits on the arctic shore of Gydan peninsula Core drilling was performed in four regions of arctic shore on Gydan peninsula. Complex laboratory analysis of cores allowed to characterize biochemistry of Gydan permafrost. These results are compared with data from other permafrost provinces and are applied for paleoreconstructions.В четырех районах арктического побережья полуострова Гыдан проведено колонковое бурение и отобраны керны мерзлых отложений. Комплекс лабораторных анализов впервые позволил дать биогеохимическую характеристику мерзлых толщ на Гыдане, сравнить полученные результаты с другими районами криолитозоны и применить их для палеореконструкций

Эоплейстоценовые отложения гыданского побережья Енисейского залива (север Западной Сибири)

In the north of Western Siberia, natural outcrops of marine Eopleistocene sediments are described. Eopleistocene age is confirmed by SIS-chemostratigraphic studies of samples. For this time, the gradual regression and desalination with the buffing was reconstructed. This is evidenced by the thin-stratification of deposits, the disappearance of foraminifera and marine mollusks and the appearance of brackish and freshwater algae and ostracods. According to the spore-pollen data, Eopleistocene time was warm, coniferous and coniferous-deciduous forests grew on the banks.Описаны естественные обнажения морских эоплейстоценовых отложений на севере Западной Сибири. Эоплейстоценовый возраст подтвержден путем SIS-хемостратиграфических исследований образцов. Для этого времени реконструировано постепенное обмеление и опреснение моря, с заболачиванием осушенного дна. Об этом свидетельствует ленточная слоистость отложений, исчезновение фораминифер и морских моллюсков и появление солоноватоводных и пресноводных водорослей и остракод. По спорово-пыльцевым данным эоплейстоценовое время было теплым, на берегах произрастали хвойные и хвойно-лиственные леса

Postglacial relative sea level change at Fildes Peninsula, King George Island (West Antarctic)

Analysis and integration of data obtained in our field and laboratory investigations of 2008–2012 together with results of previous paleogeographic studies were conducted to reveal parameters and factors of the post-glacial changes in the relative sea-level on the Fildes Peninsula and the King George Island. Results of dating of organic material taken from cross-sections of Quaternary deposits, data on morphology of marine landforms as well as on bottom sediments in lakes were used to construct a curve of changes in the relative sea-level.Our research has shown that the rapid rise of relative sea level in the area (since the beginning of the Holocene) decelerated about 8000 years BP, achieving its maximum about 7000 years BP. This was followed by the fall of relative sea-level (the land elevation) by 18–20  m in total, and it was characterized by relatively high rate of fall during periods of 6000– 5000 years BP, 4000–2500 years BP, and during the last 1500 years; the rate decreased in 5000–4000 years BP and 2500– 1600 years BP. The changes in relative sea level in this region were determined by the following factors: the eustatic component of the global changes in sea-level and, possibly, oscillations in the global sea level of another nature; local parameters of the Last glacial maximum; a course of the Peninsula deglaciation; regional physical characteristics of the Earth's crust and the mantle substances; local tectonic processes, including the isostatic rebound. Since the beginning of the Holocene up to about 7000 years BP, the main contribution to changes of the relative sea-level in this area was made by the global eustatic factor. The subsequent fall of the relative sea-level (elevation of the Peninsula surface) proceeded under condition of reduced role of the eustatic factor and predominance of other factors

Environmental conditions of interstadial (MIS 3) and features of the last glacial maximum on the King George island (West Antarctica)

The interstadial marine deposits stratum was described in the Fildes Peninsula (King George Island) due to field and laboratory investigations during 2008–2011. The stratum fragments occur in the west and north-west parts of peninsula in following forms: sections of soft sediments, containing fossil shells, marine algae, bones of marine animals and rich marine diatom complexes in situ (11 sites); fragments of shells and bones on the surface (25 sites). According to the results of radiocarbon dating, these deposits were accumulated within the period 19–50 ky BP. Geographical and altitude settings of the sites, age characteristics, taxonomy of fossil flora and fauna, and good safety of the soft deposits stratum allow to make following conclusions: during interstadial, sea water covered significant part of King George Island up to the present altitude of 40 m a.s.l., and the King George Island glaciation had smaller size then; environmental conditions for the interstadial deposit stratum accumulation were at least not colder than today; probably, the King George island territory was covered entirely by ice masses of Last glacial maximum not earlier than 19 ky BP; during Last glacial maximum, King George Island was covered by thin, «cold», not mobile glaciers, which contribute to conservation of the soft marine interstadial deposits filled with fossil flora and fauna

Условия интерстадиала (MIS3) и характер оледенения в последний ледниковый максимум на о. Кинг Джордж (Западная Антарктика)

The interstadial marine deposits stratum was described in the Fildes Peninsula (King George Island) due to field and laboratory investigations during 2008–2011. The stratum fragments occur in the west and north-west parts of peninsula in following forms: sections of soft sediments, containing fossil shells, marine algae, bones of marine animals and rich marine diatom complexes in situ (11 sites); fragments of shells and bones on the surface (25 sites). According to the results of radiocarbon dating, these deposits were accumulated within the period 19–50 ky BP. Geographical and altitude settings of the sites, age characteristics, taxonomy of fossil flora and fauna, and good safety of the soft deposits stratum allow to make following conclusions: during interstadial, sea water covered significant part of King George Island up to the present altitude of 40 m a.s.l., and the King George Island glaciation had smaller size then; environmental conditions for the interstadial deposit stratum accumulation were at least not colder than today; probably, the King George island territory was covered entirely by ice masses of Last glacial maximum not earlier than 19 ky BP; during Last glacial maximum, King George Island was covered by thin, «cold», not mobile glaciers, which contribute to conservation of the soft marine interstadial deposits filled with fossil flora and fauna.В ходе экспедиционных и лабораторных работ 2008–2012 гг. изучены распространённые на п-ове Файлдс (о. Кинг Джордж) морские отложения интерстадиала. Разрезы отложений в ненарушенном залегании, содержащие морские комплексы диатомей, раковины, водоросли и кости морских животных, исследованы в 11 точках; высыпки раковин и костей на поверхности мысов, морен и склонов долин установлены в 25 точках. Согласно радиоуглеродному датированию, эти отложения накапливались в период между 19 и 50 тыс. л.н. Пространственное и высотное положение отложений, их строение, возраст, а также особенности видового состава ископаемой флоры и фауны позволяют заключить следующее: 1) в период интерстадиала морские воды распространялись на о. Кинг Джордж как минимум до современных высотных отметок 40 м, а площадь острова и оледенения заметно сокращалась; 2) условия накопления отложений интерстадиала были, по крайней мере, не холоднее наблюдающихся в этом районе сейчас; 3) развитие оледенения последнего ледникового максимума (ПЛМ) на о. Кинг Джордж началось довольно поздно; возможно, до 19 тыс. л.н. остров не был полностью покрыт льдом; 4) оледенение ПЛМ на о. Кинг Джордж было маломощным, малоподвижным («холодного» типа) и, вероятно, было представлено несколькими ледниками с низкими потенциалом экзарации и способностью «консервировать» древние отложения