Variations in the geochemical composition of dolerites of the Sette-Daban event

<p>Sette-Daban LIP-related event [<strong>1</strong>] was dated by U-Pb baddeleyite and Sm-Nd isochron methods, but very limited information has been published on the geochemical and isotopic compositions of the associated igneous rocks. This work presents a new dating and the largest geochemical base of samples from the Sette-Daban event.</p><p>Mafic sills of the Sette-Daban event are most widespread in the upper part of the Lakhanda Group and lower part of the Uy Group (Maya-Kyllakh zone). Two intrusions were dated by the U-Pb baddeleyite method, yielding ages of 1005 &#177; 4 Ma - Sakhara river and 974 &#177; 7 Ma - Allakh-Yun river [<strong>2</strong>]. Isotope dating of a sublatitudinal dike in the Belaya River area gave an age which overlaps the already known dating along the Sakhara river.</p><p>Studied samples from the rivers Yudoma and Allah-Yun confirmed the already obtained result from the previous work [<strong>3</strong>]. The Sette-Daban dolerite sills resemble low-Ti lavas of intraplate flood basalt provinces (e.g., Karoo, Siberian Traps) and possess IAB-like trace element patterns.</p><p>In turn, samples from the Belaya River are enriched more strongly and closer to the OIB distribution. The rare earth elements contents (e.g., La, Ce, Pr, Nd, Sm) in Belaya samples is 2-5 times higher than in Yudoma. However, &#949;Nd(T) values vary from 4.3 to 6.3 which corresponds to the already known range of values for the Sette-Daban complex.</p><p>Thus, detailed geochemical studies made it possible to identify a new zone (Belaya) in the Sette-Daban complex, which has significant differences from the previously obtained values.</p><p>The studies were supported by the Russian Science Foundation grant No. 19-77-10048.</p><p><strong>&#160;</strong></p><p>References:</p><p>[<strong>1</strong>] Ernst, R.E. Large Igneous Provinces. In Large Igneous Provinces; Ernst, R.E., Ed.; Cambridge University Press: Cambridge, UK, 2014; p. 653. ISBN 9780521871778.</p><p>[<strong>2</strong>] Rainbird, R.H.; Stern, R.A.; Khudoley, A.K.; Kropachev, A.P.; Heaman, L.M.; Sukhorukov, V.I. U-Pb geochronology of Riphean sandstone and gabbro from southeast Siberia and its bearing on the Laurentia-Siberia connection. Earth Planet. Sci. Lett. 1998, 164, 409&#8211;420. </p><p>[<strong>3</strong>] Savelev, A.D.; Malyshev, S.V.; Savatenkov, V.M.; Ignatov, D.D.; Kuzkina, A.D. Meso-Neoproterozoic Mafic Sills along the South-Eastern margin of the Siberian Craton, SE Yakutia: Petrogenesis, Tectonic and Geochemical features. Minerals 2020, 10, 805. </p>