Middle Paleozoic basic magmatism of the northwestern Vilyui Rift: Composition, sources, and geodynamics

Radiating rifts and dyke swarms of the middle Paleozoic Yakutsk plume of eastern Siberian craton

“…Kimberlites from the Mir pipe (Mirnyi field) cut across a sill and dyke of the Middle Paleozoic Yakutsk event. Kimberlites from the Nyurba pipe (Nakyn field) are cut by composite dykes of dolerite-monzonite porphyries, but these kimberlites contain xenoliths of dolerites (Kiselev et al, 2006). Therefore, the time sequence of the Middle Paleozoic (Yakutsk event) magmatism in the Vilyui rift region is as follows: dolerite dykes -kimberlites -local post-kimberlite dolerite dykes.…”

“…Trachybasalts and trachyandesites in the southwestern part of the Vilyui rift with total thickness up to 750 m represent the early alkaline series. Moderately tholeiitic basalts, are also common within all parts of the rift, and define the Late Series which has a cumulative thickness of a few to 200 m (Kiselev et al, 2006(Kiselev et al, , 2007. The Upper Devonian age of these effusive rocks was determined from paleontological data.…”

“…11), the samples fall in the depleted quadrant (upper left) and upper right. The data are considered in terms of the mixing of sources, both depleted and enriched in radiogenic Sr (Kiselev et al, 2006).…”

Paleozoic large igneous provinces of Northern Eurasia: Correlation with mass extinction events

“…On the basis of paleomagnetic data, Kravchinsky et al (2002) suggested that the major stage of Viluy trap magmatism could have occurred in a relatively short time interval around the Frasnian-Famennian boundary and that this stage correlates well with the mass extinction during this time. Scarce Ar-Ar data indicate that the magmatism age ranges within 380-350 Ma (Kiselev et al, 2006). Recent absolute dating of samples using both K/Ar and 40 Ar/ 39 Ar techniques demonstrated that the major phase of Viluy magmatism could indeed have been restricted to the period 360-370 Ma.…”

“…The triple-junction rift system was formed during the Devonian Period (Kuzmin et al, 2010); the Viluy rift is the western remaining branch of the system and two other branches form the modern margin of the Siberian Platform. The Viluy rift is 800 km long and 450 km wide (Kiselev et al, 2006). Volcanic rocks are covered with post Late Devonian-Early Carboniferous sediments.…”