关键词: 基性岩“球粒”, 杏仁体, 碳, 氧同位素, 塔里木盆地

Abstract: Characteristic and origin of “spherical particle” are studied based on contrast analysis of petrography and carbon and oxygen isotope of “spherical particles” in basite drawn from well and typical amygdules in basalt sampled in the field. Results show that “spherical particles” and amygdules are significantly different in microscopic and carbon and oxygen isotopic characteristics although they are similar in macroscopic feature. “Spherical particles” are characterized by non-oscillatory zoning, obvious recrystallization in the rim, and different carbon and oxygen isotopic values in different “spherical particle” of the same sample. Amygdules are characterized by oscillatory zoning, big crystalline particle, and similar carbon and oxygen isotopic values in different amygdule of the same sample. It can be concluded that “spherical particle” stems from magma capturing pieces of sedimentary carbonate, rather than secondary minerals filling vent. As a result, the basite drilled from the Cambrian and Carboniferous strata is intrusive rock, and volcanism may not occur in related strata.

Key words: “spherical particles” in basite, amygdules, carbon and oxygen isotope, Tarim Basin