Paleomagnetic dating of Phanerozoic kimberlites in Siberia

Diamond bearing kimberlite pipes are exposed across the north-central part of the Siberian platform. Three main time intervals are considered to be the age of emplacement: the Devonian–Early Carboniferous, Triassic, and Cretaceous. However, isotopic age data from of the pipes are scattered and provide a very broad age interval for the magmatic activity. New paleomagnetic poles from four kimberlite pipes (Eastern Udachnaya, Western Udachnaya, International and Obnazhennaya) are obtained to estimate their paleomagnetic age. The mean primary magnetization directions for the pipes are as follows: D = 4.3°, I = − 44.5° (k = 29.4, α95 = 7.4°, N = 14); D = 340.5°, I = − 65.6° (k = 12.9, α95 = 19.4°, N = 6); D = 291.1°, I = − 78.1° (k = 27.5, α95 = 14.9°, N = 5); and D = 306.7°, I = − 82.6° (k = 38.4, α95 = 5.8°, N = 17), respectively. On the basis of a comparison with the Siberian apparent polar wander path (APWP) we estimate the age of kimberlite magmatism, assuming primary magnetizations in these rocks. The paleomagnetic ages are as follows: 428 ± 13 Ma for Eastern Udachnaya; 251 ± 30 Ma for International pipe; and 168 ± 11 Ma for Obnazhennaya pipe. The Western Udachnaya pipe was remagnetized and no clear paleomagnetic age could be determined. The ages of magmatic activity span the Early Silurian to Middle Late Jurassic. Early Silurian magmatism could be associated with the formation of the Viluy rift. Middle to Late Jurassic magmatic activity is most likely related to subduction related to the accretion of surrounding terranes to Siberia.

► Paleomagnetism is applied to date kimberlite magmatism in Siberia for the first time. ► Paleomagnetic dating spans ages from Early Silurian to Middle–Late Jurassic. ► Paleomagnetic dating refines previously obtained or imprecise ages.