DOI: 10.1016/j.epsl.2017.12.009
Scopus记录号: 2-s2.0-85038210550
论文题名: A high-resolution paleosecular variation record from Black Sea sediments indicating fast directional changes associated with low field intensities during marine isotope stage (MIS) 4
作者: Nowaczyk N.R. ; Jiabo L. ; Frank U. ; Arz H.W.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 484 起始页码: 15
结束页码: 29
语种: 英语
英文关键词: Black Sea
; geomagnetic excursion
; magnetostratigraphy
; paleosecular variation
; XRF-scanning
Scopus关键词: Geomagnetism
; Glacial geology
; Isotopes
; Mass spectrometry
; Submarine geology
; Accelerator mass spectrometry
; Black sea
; Directional variation
; Geomagnetic excursions
; Magnetostratigraphy
; Marine isotope stages
; Paleosecular variations
; Relative paleointensity
; Sediments
; geomagnetic field
; geomagnetism
; magnetostratigraphy
; marine isotope stage
; marine sediment
; paleointensity
; paleomagnetism
; secular variation
; X-ray fluorescence
; Arctic
; Black Sea
; Greenland
英文摘要: A total of nine sediment cores recovered from the Archangelsky Ridge in the SE Black Sea were systematically subjected to intense paleo- and mineral magnetic analyses. Besides 16 accelerator mass spectrometry (AMS) 14C ages available for another core from this area, dating was accomplished by correlation of short-term warming events during the last glacial monitored by high-resolution X-ray fluorescence (XRF) scanning as maxima in both Ca/Ti and K/Ti ratios in Black Sea sediments to the so-called ‘Dansgaard–Oeschger events’ recognized from Greenland ice cores. Thus, several hiatuses could be identified in the various cores during the last glacial/interglacial cycle. Finally, core sections documenting marine isotope stage (MIS) 4 at high resolution back to 69 ka were selected for detailed analyses. At 64.5 ka, according to obtained results from Black Sea sediments, the second deepest minimum in relative paleointensity during the past 69 ka occurred, with the Laschamp geomagnetic excursion at 41 ka being associated with the lowest field intensities. The field minimum during MIS 4 is associated with large declination swings beginning about 3 ka before the minimum. While a swing to 50°E is associated with steep inclinations (50–60°) according to the coring site at 42°N, the subsequent declination swing to 30°W is associated with shallow inclinations of down to 40°. Nevertheless, these large deviations from the direction of a geocentric axial dipole field (I=61°, D=0°) still can not yet be termed as ‘excursional’, since latitudes of corresponding virtual geomagnetic poles (VGP) only reach down to 51.5°N (120°E) and 61.5°N (75°W), respectively. However, these VGP positions at opposite sides of the globe are linked with VGP drift rates of up to 0.2° per year in between. These extreme secular variations might be the mid-latitude expression of a geomagnetic excursion with partly reversed inclinations found at several sites much further North in Arctic marine sediments between 69°N and 81°N. Thus, the pronounced intensity minimum at 64.5 ka and described directional variations might be the effect of a weak geomagnetic field with a multi-polar geometry in the middle of MIS 4. © 2017 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/110059
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
There are no files associated with this item.
作者单位: Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Section 5.2 – Paleoclimate and Landscape evolution, Potsdam, 14473, Germany; Leibnitz Institute for Baltic Sea Research, Warnemünde, Rostock, 18119, Germany
Recommended Citation:
Nowaczyk N.R.,Jiabo L.,Frank U.,et al. A high-resolution paleosecular variation record from Black Sea sediments indicating fast directional changes associated with low field intensities during marine isotope stage (MIS) 4[J]. Earth and Planetary Science Letters,2018-01-01,484