INTENSITY INDICATORS OF GEODYNAMIC PROCESSES ALONG THE ATLANTIC-ARCTIC RIFT SYSTEM

Seismicity, heat flow, seismic tomography data, prerift and synrift magmatism are considered as intensity indicators of geodynamic processes along the Atlantic-Arctic rift system (AARS). In this rift system, several large (over 100 km ) sub-latitudinal displacements of the rift axis are due to left-lateral strike-slip faulting. The AARS segments are distinguished by the age of splitting of continental plates from each other. A dependence is revealed between the current thermal state of the mantle under the AARS and the age of spreading start. This dependence is established from both seismic tomography and heat flow data. In section δ(Vp/Vs), the locations of the main segmenting faults and ‘cold’ anomalies in the upper mantle are coincident. Distributions of total seismic moments are practically synchronous in the depth intervals of 0–13, 13–35, and >35 km. The maximum values above the plumes are represented by higher seismic moments in the surface layer. The main demarcation zones differ in maximum energy release values in the AARS with shearing features. Comparison of these values against the age of the start of spreading processes shows trends of heat flow and medium field tomography in the AARS segments. The trends confirm the thermal interpretation of the seismic tomography data and suggest mantle cooling with age and a decrease in the mean temperatures of the mantle. The main factor causing the sublatitudinal asymmetry of heat flow in the AARS is the impact of Coriolis forces on the magma in the asthenospheric source. Most of the synrift igneous formations seem to be related to the influence of long-lived anomalies in the mantle, which had lower rates of magma generation than those typical of the formation of magmatic provinces. In conditions for spreading and the formation of the oceanic crust, the process followed the principle of energy cost minimization, and the prerift magmatic provinces with the pre-processed crust contributed to the choice and positioning of the AARS trajectory. The plume branches are imposed in the tomographic section and thus ‘concealing’ the relationship between the age and the thermal state. However, that does not change the trend to cooling of the mantle beneath the AARS, proportionally to the time since the start of spreading.

1. ANSS Earthquake Composite Catalog, 2014. Available from: http://quake.geo.berkeley.edu/anss/ (Last Accessed 11.02.2014).

2. Aplonov S.V., Trunin A.A., 1995. Migration of Local Spreading Instability along the Divergent Boundary Axis: MidAtlantic Ridge Between Marathon and Kane Transform Faults. Physics of the Earth 9, 24–34 (in Russian) [Аплонов С.В., Трунин А.А. Миграция локальной нестабильности спрединга вдоль оси дивергентной границы: Срединно-Атлантический хребет между трансформными разломами Марафон и Кейн // Физика Земли. 1995. № 9. С. 24–34].

3. Becker T.W., Boschi L., 2002. A Comparison of Tomographic and Geodynamic Mantle Models. Geochemistry, Geophysics, Geosystems 3 (1), 2001GC000168. https://doi.org/10.1029/2001GC000168.

4. Boldyrev S.A., 1998. Seismogeodynamics of the MidAtlantic Range. MGC, Moscow, 124 p. (in Russian) [Болдырев С.А. Сейсмогеодинамика Срединно-Атлантического хребта. М.: МГК, 1998. 124 с.].

5. Bonatti E., 1996. Origin of the Large Fracture Zones Offsetting the Mid-Atlantic Ridge. Geotectonics 30 (6), 430–440.

6. Bryan S., Ernst R., 2007. Revised Definition of Large Igneous Province (LIPs). Earth Science Reviews 86 (1–4), 175– 202. https://doi.org/10.1016/j.earscirev.2007.08.008.

7. Dmitriev L.V., Silantiev S.A., Sokolov S.Yu., Plechov A.A., 2000. The Comparison of Basalt Magmatism in the Conditions of Different Velocity of Spreading by the Example of the Mid-Atlantic Ridge and the East Pacific Rise. Russian Journal of Earth Sciences 2 (3), 207–226 (in Russian) [Дмитриев Л.В., Силантьев С.А., Плечова А.А., Соколов С.Ю. Сравнение базальтового магматизма в условиях разной скорости спрединга на примере Срединно-Атлантического хребта (САХ) и Восточно-Тихоокеанского поднятия (ВТП) // Российский журнал наук о Земле. 2000. Т. 2. № 3. C. 207–226]. https://doi.org/10.2205/2000ES000041.

8. Dmitriev L.V., Sokolov S.Y., 2003. Geodynamics of Three Contrasting Types of Oceanic Magmatism and Their Reflection in the Data of Seismic Tomography. Petrology 11 (6), 597–613.

9. Eldholm O., Coffin M.F., 2000. Large Igneous Provinces and Plate Tectonics. In: M.A. Richards, R.G. Gordon, R.D. Van der Hilst (Eds), The History and Dynamics of Global Plate Motions. AGU Geophysical Monograph Series, Vol. 121, p. 309–326. https://doi.org/10.1029/GM121p0309.

10. Foster S.E., Simmons G., Lamb W., 1974. Heat Flow near a North Atlantic Fracture Zone. Geothermics 3 (1), 3–16. https://doi.org/10.1016/0375-6505(74)90030-3.

11. Gaina C., Medvedev S., Torsvik T.H., Koulakov I., Werner S.C., 2013. 4D Arctic: A Glimpse into the Structure and Evolution of the Arctic in the Light of New Geophysical Maps, Plate Tectonics and Tomographic Models. Surveys in Geophysics 35 (5), 1095–1122. https://doi.org/10.1007/s10712-013-9254-y.

12. Global Heat Flow Database, 2018. University of North Dakota. Available from: https://engineering.und.edu/research/global-heat-flow-database/data.html.

13. Grand S.P., van der Hilst R.D., Widiyantoro S., 1997. Global Seismic Tomography: A Snapshot of Convection in the Earth. GSA Today 7 (4), 1–7.

14. Karyakin Y.V., Shipilov E.V., 2009. Geochemical Specifics and 40Ar/39Ar Age of the Basaltoid Magmatism of the Alexander Land, Northbrook, Hooker, and Hayes Islands (Franz Josef Land Archipelago). Doklady Earth Sciences 425 (1), 260– 263. https://doi.org/10.1134/s1028334x09020196.

15. Kharin G.S., 2000. Impulses of magmatism of the Icelandic plume. Petrology 8 (2), 115–130 (in Russian) Харин Г.С. Импульсы магматизма Исландского плюма // Петрология. 2000. Т. 8. № 2. С. 115–130.

16. Khutorskoi M.D., Polyak B.G., 2017. Special Features of Heat Flow in Transform Faults of the North Atlantic and Southeast Pacific. Geotectonics 51 (2), 152–162. https://doi.org/10.1134/s0016852117010022.

17. Khutorskoy M.D., Teveleva E.A., 2018. Asymmetry of the Heat Fluw at the Mid-Oceanic Ridges in the Northern and Southern Hemispheres. Georesources 20 (2), 122–132 (in Russian) [Хуторской М.Д., Тевелева Е.А. Асимметрия теплового потока на срединно-океанических хребтах в Северном и Южном полушариях Земли // Георесурсы. 2018. Т. 20. № 2. С. 122–132]. https://doi.org/10.18599/grs.2018.2.122-132.

18. Klein E.M., Langmuir C.H., 1987. Global Correlation of Ocean Ridge Basalt Chemistry with Axial Depth and Crustal Thickness. Journal of Geophysical Research 92 (B8), 8089– 8115. https://doi.org/10.1029/JB092iB08p08089.

19. Lebedev S., van der Hilst R.D., 2008. Global Upper-Mantle Tomography with the Automated Multimode Inversion of Surface and S-Wave Forms. Geophysical Journal International 173 (2), 505–518. https://doi.org/10.1111/j.1365-246X.2008.03721.x.

20. Ledneva G.V., Bazylev B.A., Layer P.W., Ishiwatari A., Sokolov S.D., Kononkova N.N., Tikhomirov P.L., Novikova M.S., 2014. Intra-Plate Gabbroic Rocks of Permo-Triassic to EarlyMiddle Triassic Dike-and-Sill Province of Chukotka (Russia). In: D.B. Stone, G.E. Grikurov (Eds), ICAM VI: Proceedings of the International Conference on Arctic Margins VI (Fairbanks, Alaska, May 2011). VSEGEI Publishing House, Saint Petersburg, p. 115–156.

21. Ledneva G.V., Pease V.L., Sokolov S.D., 2011. Permo-Triassic Hypabyssal Mafic Intrusions and Associated Tholeiitic Basalts of the Kolyuchinskaya Bay, Chukotka (NE Russia): Links to the Siberian LIP. Journal of Asian Earth Science 40 (3), 737– 745. https://doi.org/10.1016/j.jseaes.2010.11.007.

22. Lukina N.V., Patyk-Kara N.G,. Sokolov S.Yu., 2004. Neotectonic Structures and Active Faults of the Arctic Shelf of Russia. In: M.N. Alekseeva (Ed.), Geology and Mineral Resources of the Russian Shelf Areas. Atlas. Nauchny Mir, Moscow, p. 3 (in Russian) [Лукина Н.В., Патык-Кара Н.Г., Соколов С.Ю. Неотектонические структуры и активные разломы Арктического шельфа России // Геология и минеральные ресурсы шельфов России. Атлас / Ред. М.Н. Алексеева. М.: Научный мир, 2004. С. 3].

23. Lundin E.R., Doré A.G., Redfield T.F., 2018. Magmatism and Extension Rates at Rifted Margins. Petroleum Geoscience 24 (4), 379–392. https://doi.org/10.1144/petgeo2016-158.

24. Michael P.J., Langmuir C.H., B. Dick H.J., Snow J.E., Goldstein S.L., Graham D.W., Lehnert K., Kurras G., Jokat W., Muhe R., Edmonds H.N., 2003. Magmatic and Amagmatic Seafloor Generation at the Ultraslow-Spreading Gakkel Ridge, Arctic Ocean. Nature 423 (6943), 956–961. https://doi.org/10.1038/nature01704.

25. Müller R.D., Sdrolias M., Gaina C., Roest W.R., 2008. Age, Spreading Rates, and Spreading Asymmetry of the World’s Ocean Crust. Geochemistry, Geophysics, Geosystems 9 (4), Q04006. https://doi.org/10.1029/2007GC001743.

26. Piskarev A.L., Heunemann C., Makar’ev A.A., Makar’eva A.M., Bachtadse V., Aleksyutin M., 2009. Magnetic Parameters and Variations in the Composition of Igneous Rocks of the Franz Josef Land Archipelago. Izvestiya, Physics of the Solid Earth 45 (2), 150–166. https://doi.org/10.1134/s1069351309020050.

27. Piskarev A.L., Poselov V.A., Avetisov G.P., Butsenko V.V., Glebovsky V.Yu., Gusev E.A., Zholondz S.M., Kaminsky V.D., Kireev A.A., Smirnov O.E., Firsov Yu.G., Zinchenko A.G., Pavlenkin A.D., Poselova L.G., Savin V.A., Chernykh A.A., Elkina D.V., 2016. Arctic Basin (Geology and Morphology). VNIIOkeangeologia, Saint Petersburg, 291 p. (in Russian) [Пискарев А.Л., Поселов В.А., Аветисов Г.П., Буценко В.В., Глебовский В.Ю., Гусев Е.А., Жолондз С.М., Каминский В.Д., Киреев А.А., Смирнов О.Е., Фирсов Ю.Г., Зинченко А.Г., Павленкин А.Д., Поселова Л.Г., Савин В.А., Черных А.А., Элькина Д.В. Арктический бассейн (геология и морфология). СПб.: ВНИИОкеангеология, 2016. 291 с.].

28. Podgornykh L.V., Khutorskoy M.D., 1997. Planetary Heat Flow Map. Scale 1:30000000. Explanatory Note. Publishing House of Oceanology Institute, Moscow, Saint Petersburg, 33 p. (in Russian) [Подгорных Л.В., Хуторской М.Д. Карта планетарного теплового потока. Масштаб 1:30000000. Объяснительная записка. М.–СПб.: Изд-во ВНИИОкеангеология, 1997. 33 с.].

29. Polyak B.G., Kononov V.I., Khutorskoy M.D., 1984. Heat Flow and the Lithosphere Structure of Iceland in the Light of New Data. Geotectonics 1, 111–119 (in Russian) [Поляк Б.Г., Кононов В.И., Хуторской М.Д. Тепловой поток и строение литосферы Исландии в свете новых данных // Геотектоника. 1984. № 1. С. 111–119].

30. Popova A.K., Smirnov Ya.B., Khutorskoy M.D., 1984. Geothermal Field of Transform Faults. In: Yu.P. Neprochnov (Ed.), Deep Faults of the Oceanic Floor. Nauka, Moscow, p. 78–87 (in Russian) [Попова А.К., Смирнов Я.Б., Хуторской М.Д. Геотермическое поле трансформных разломов // Глубинные разломы океанского дна / Ред. Ю.П. Непрочнов. М.: Наука, 1984. С. 78–87].

31. Shipilov E.V., 2004. Tectono-Geodynamic Evolution of Arctic Continental Margins during Epochs of Young Ocean Formation. Geotectonics 38 (5), 343–365.

32. Shipilov E.V., Karyakin Y.V., Matishov G.G., 2009. Jurassic-Cretaceous Barents-Amerasian Superplume and Initial Stage of Geodynamic Evolution of the Arctic Ocean. Doklady Earth Sciences 426 (1), 564–566. https://doi.org/10.1134/s1028334x09040126.

33. Sokolov S.Yu., 2014. The State of Geodynamic Mobility in the Mantle According to Seismic Tomography and the Ratio of P- and S-Wave Velocities. Bulletin of Kamchatka Regional Association "Educational-Scientific Center". Earth Sciences (2), 55–67 (in Russian) [Соколов С.Ю. Состояние геодинамической подвижности в мантии по данным сейсмотомографии и отношению скоростей Р и S волн // Вестник КРАУНЦ. Науки о Земле. 2014. № 2. С. 55–67.].

34. Sokolov S.Yu., 2016. Features of Tectonics of the MidAtlantic Ridge According to the Correlation of Surface Parameters with the Geodynamic State of the Upper Mantle. Bulletin of Kamchatka Regional Association "EducationalScientific Center". Earth Sciences (4), 88–105 (in Russian) [Соколов С.Ю. Особенности тектоники Срединно-Атлантического хребта по данным корреляции поверхностных параметров с геодинамическим состоянием верхней мантии // Вестник КРАУНЦ. Науки о Земле. 2016. № 4. С. 88–105].

35. Sokolov S.Yu., 2017. Atlantic-Arctic Rift System: an Approach to the Geodynamic Description According to Seismic Tomography and Seismicity. Bulletin of Kamchatka Regional Association "Educational-Scientific Center". Earth Sciences (4), 79–88 (in Russian) [Соколов С.Ю. Атлантико-Арктическая рифтовая система: подход к геодинамическому описанию по данным сейсмической томографии и сейсмичности // Вестник КРАУНЦ. Науки о Земле. 2017. № 4. С. 79–88].

36. Sokolov S.Yu., 2018. Tectonics and Geodynamics of the Equatorial Segment of the Atlantic. Proceedings of GIN RAS. Issue 618. Nauchny Mir, Moscow, 269 p. (in Russian) [Соколов С.Ю. Тектоника и геодинамика экваториального сегмента Атлантики. Труды ГИН РАН. Вып. 618. М.: Научный мир, 2018. 269 с.].

37. Sorokhtin O.G., 1974. Global Evolution of the Earth. Nauka, Moscow, 184 p. (in Russian) [Сорохтин О.Г. Глобальная эволюция Земли. М.: Наука, 1974. 184 с.].

38. Tarakhovsky A.N., Fishman M.V., Shkola I.V., Andreichev V.L., 1982. The Age of Franz Joseph Land Trappes. Reports of the USSR Academy of Sciences 266 (4), 965–969 (in Russian) [Тараховский А.Н., Фишман М.В., Школа И.В., Андреичев В.Л. Возраст траппов Земли Франца-Иосифа // Доклады АН СССР. 1982. Т. 266. № 4. С. 965–969]. Van der Hilst R.D., Widiyantoro S., Engdahl E.R., 1997. Evidence for Deep Mantle Circulation from Global Tomography. Nature 386 (6625), 578–584. https://doi.org/10.1038/386578a0.

39. Zarayskaya Yu.A., 2013. Seismic Activity of Strong Volcanic Eruptions of Ultra-Slow Spreading Ridges of Gakkel, Southwest Indian and Reykjanes. In: Geology of Seas and Oceans. Materials of the XX International Scientific Conference (School) on Marine Geology. Vol. V. GEOS, Moscow, p. 111–115 (in Russian) [Зарайская Ю.А. Сейсмическая активность сильных вулканических извержений ультра-медленных спрединговых хребтов Гаккеля, ЮгоЗападного Индийского и Рейкьянес // Геология морей и океанов: Материалы XX Международной научной конференции (Школы) по морской геологии. М.: ГЕОС, 2013. Т. V. C. 111–115].