Rock Magnetic Records of Baluchabad Loess-Paleosol Sequences, Northern Iran

سال انتشار: 1400
محل انتشار: دومین کنفرانس بین المللی کواترنری
کد COI اختصاصی: IQA04_046
زبان مقاله: انگلیسی
تعداد مشاهده: 295

نویسندگان

Dept. of Soil Science, Gorgan University of Agricultural Sciences and Natural Resources, Iran- Leibniz Institute for Applied Geophysics (LIAG), Germany

I Khormali

Dept. of Soil Science, Gorgan University of Agricultural Sciences and Natural Resources, Iran

J-D Huxol

Dept. of Geography, Cologne University, Germany

C Zeeden

Leibniz Institute for Applied Geophysics (LIAG), Germany

C Rolf

Leibniz Institute for Applied Geophysics (LIAG), Germany

M Frechen

چکیده

Loess sediments of northern Iran reflect several cycles of climate change for the Quaternary period andrepresent one of the most important terrestrial archives for the area. In addition, they form a bridge betweenEuropean and Asian loess sediments (Frechen et al., ۲۰۰۹), needed for stratigraphic correlation.Deciphering the nature of glacial and interglacial paleoenvironment is also crucial for understanding thefuture climate. Mineral magnetic methods play a key role in paleoclimate reconstructions since magneticsusceptibility in loess is highly sensitive to environmental change during pedogenesis. In fact, basicfrequency-dependent magnetic susceptibility analysis has become a routine stratigraphic tool in studies ofloess sequences. The formation of superparamagnetic particles can also drive the enhancement of low fieldsusceptibility (χlf), which is why both χlf and frequency-dependent susceptibility (χfd) have been usedindependently as proxies for climate-driven pedogenesis (Balsam et al., ۲۰۱۱). The Baluchabad profile islocated in Golestan province of Iran, the section was morphologically described according to keys to SoilTaxonomy ۲۰۱۴. Therefore, the modern soil was classified as Typic Haploxerept. Samples for magneticsusceptibility analysis were taken at every ۴ cm. The samples were dried, homogenized and pressed intoplastic cubes (۶.۴ cm۳) and studied at the rock paleomagnetic laboratory of the Leibniz Institute for AppliedGeophysics (LIAG). Magnetic susceptibility was measured using a frequency and field variable MagnonVSM Susceptibility Bridge at ۵۰۵ and ۵۰۵۰ Hz (Rolf et al., ۲۰۱۴), and finally the χfd was calculated. In theBaluchabad profile, we found several paleosols with varying weathering degrees that are welldistinguishable by magnetic susceptibility data. The χlf value was from ~ ۲۲.۲×۱۰-۸ m۳/Kg to ۲۰۳.۷×۱۰-۸m۳/Kg which corresponds to loess (C and Bk horizons) and paleosol (Bt horizon) respectively, this is inline with previous studies about increasing magnetic susceptibility in paleosols. Maximum χlf valuesindicating the effects of pedogenesis on the increase of magnetic minerals. The large differences of χlfvalues between loess and paleosols have been great enough to easily differentiate the loess from paleosols.Based on the magnetic results and field observations of the Baluchabad profile, at least three glacial periodsand three interglacial periods can be distinguished. The interglacial periods are represented bypedocomplexes which can probably be related to Marine Isotope Stage (MIS) ۵, MIS ۷ and MIS ۹.

کلیدواژه ها

Quaternary period, Pedostratigraphy, Magnetic Susceptibility

مقالات مرتبط جدید

اطلاعات بیشتر در مورد COI

COI مخفف عبارت CIVILICA Object Identifier به معنی شناسه سیویلیکا برای اسناد است. COI کدی است که مطابق محل انتشار، به مقالات کنفرانسها و ژورنالهای داخل کشور به هنگام نمایه سازی بر روی پایگاه استنادی سیویلیکا اختصاص می یابد.

کد COI به مفهوم کد ملی اسناد نمایه شده در سیویلیکا است و کدی یکتا و ثابت است و به همین دلیل همواره قابلیت استناد و پیگیری دارد.