کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9522193 | 1634954 | 2005 | 16 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Palaeomagnetic data from Ediacaran (Vendian) sediments of the Arkhangelsk region, NW Russia: An alternative apparent polar wander path of Baltica for the Late Proterozoic-Early Palaeozoic
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
علوم زمین و سیاره ای (عمومی)
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Palaeomagnetic data from Ediacaran (Vendian) sediments of the Arkhangelsk region, NW Russia: An alternative apparent polar wander path of Baltica for the Late Proterozoic-Early Palaeozoic Palaeomagnetic data from Ediacaran (Vendian) sediments of the Arkhangelsk region, NW Russia: An alternative apparent polar wander path of Baltica for the Late Proterozoic-Early Palaeozoic](/preview/png/9522193.png)
چکیده انگلیسی
The study area is situated along the Zolotica river in NW Russia, located within the Kola-Dvyna Rift System in the Baltic Shield that developed during Meso and Neoproterozoic times. A 9-m thick section made up of shallow marine sediments of Upper Ediacaran age was sampled in this locality. Two volcaniclastic levels from the middle part of the section yielded an age of â¼556 Ma. (U/Pb SHRIMP-II on zircons). Two magnetic components were successfully isolated, component A (Decl = 157.1, Incl = 68.0, α95 = 1.9°, N = 575 in situ) carried by magnetite and component B (Decl = 120.3, Incl = â 31.7, α95 = 3.9°, N = 57, bedding corrected), carried by haematite. While component A is thought to represent a younger overprint direction, the in situ direction for component B on the other hand, is dissimilar to any expected younger direction and is considered to be primary magnetisation in origin, acquired during or soon after deposition of the sediments in the Late Ediacaran. The corresponding palaeomagnetic pole for component A in situ is located at Lon = 55.4°E, Lat = 31°N, A95 = 2.7° and for component B at Lon = 110°E, Lat = 28.3°S, A95 = 3.8°, N = 57. Combined with other palaeomagnetic poles of the same tectonostratigraphic unit an alternative apparent polar wander path for the Late Proterozoic-Early Palaeozoic of Baltica is proposed. Such an alternative path shows that after the mid Cryogenian (750 Ma), the poles that were situated over South Africa (p.d.c.) moved to the east until they reached Australia during the Late Ediacaran (555 Ma) where they remained approximately stationary until the beginning of the Cambrian (â¼545 Ma). Finally, they moved to the northwest until they reached the Arabian Peninsula in the Early Ordovician. Palaeolatitudes indicate that Baltica situated near the equator from the Cryogenian through to the Ediacaran moving gradually to the south at c. 1 cm/yr. During the Late Early Ediacaran, the plate suddenly began to drift northward at c. 8 cm/yr and in the boundary with the Cambrian it was positioned in low to intermediate latitudes. Finally, Baltica began to move back to the south at c. 13 cm/yr until in the Early Ordovician, reaching intermediate to high southern latitudes.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Earth and Planetary Science Letters - Volume 240, Issues 3â4, 15 December 2005, Pages 732-747
Journal: Earth and Planetary Science Letters - Volume 240, Issues 3â4, 15 December 2005, Pages 732-747
نویسندگان
MarÃa Paula Iglesia Llanos, Jennifer Alice Tait, Viktor Popov, Alexandra Abalmassova,