Birch Mountains kimberlite field shales interbedded with kimberlite at some of the diatremes are consistent with a Late Cretaceous age (Late Albian to Maastrichtian). The volcanic rocks of the BM field consist primarily of crater-facies pyroclastic kimberlite and resedimented kimberlite. They include massive layers, as well as bedded and graded layers of coarse lapilli alternating with layers of finer tuff. Lapilli and olivine phenocrysts are set in a grey-green matrix of serpentine, carbonate minerals (calcite, dolomite and magnesite) and clay minerals. Phlogopite, oxide minerals (ilmenite, perovskite and spinel), apatite and pyrite are also present. Diamonds and microdiamonds have been recovered from samples taken from
Tianshan Volcanic Group Chinese army) said that when climbing the Tianshan Mountains, saw "The Fire Mountains which send out masses of molten rock which flow for many Li" Tianshan Volcanic Group The Tianshan Volcanic Group is a volcanic field in the Tianshan Mountains in Northwest China. The historically active Cone of Pechan is within the group (also known as Peishan, Baishan, Hochan, Aghie, Bichbalick, Khala, and Boschan). The volcano is 440 km southwest of Urmqui, Xinjiang. Two eruptions are known from Tianshan, in 50 AD (± 50 years)and 650 AD (± 50 years). The book, Aspects of Nature in Different Lands and Different