Abstract. Secondary ion mass spectrometry (SIMS) is a widely used technique for in situ U–Pb geochronology of accessory minerals. Existing algorithms SIMS data reduction and error propagation make number simplifying assumptions that degrade the precision accuracy resulting dates. This paper uses an entirely new approach to processing introduces following improvements over previous algorithms. F...

The Ingur alkaline granite massif and the associated Zr-Nb occurrence make up part of largest Mongolian-Trans-Baikal granitoid provinces. is composed arfvedsonite, biotite, alaskite granites. High content HREE determines low La/Yb n (2–7) value a negative europium anomaly (Eu/Eu*≈0.17). They are depleted in Ba, Sr enriched Nb, Ta, Zr, Hf Y. According to their geochemical properties rocks belong...

Unusually radiogenic Pb has been found in sediments of a portion of the Ashtabula River (80 o 48’ W, 41 o 54’ N) near its confluence with Lake Erie. Pb isotopic compositions have been determined by quadrupole ICPMS, revealing that the Pb results from mixing of three sources: crustal Pb, common Pb from industrial pollutant sources, and highly radiogenic Pb associated with U-containing accessory ...

The Zhangwu-Heishan area is located in the east of Fuxin-Yixian basin. Besides Quaternary soil, study mostly covered with volcanic rock. horizon and age rock play an essential role understanding fossil beds, structures, sedimentary evolution West Liaoning Province coal seeking. During this work, 11 samples were measured by SHRIMP U-Pb isotope analysis. Based on reported data Mesozoic Province, ...

Numerous post-ophiolite intrusions exposed into the late Cretaceous–Paleocene Sabzevar ophiolite belt, northeast Iran. The intrusions consist of calc-alkaline intermediate to felsic rocks with metaluminous to peraluminous in nature and adakitic affinities. Based on U-Th-Pb dating on separated zircons by SHRIMP Ⅱ, the emplacement age of these rocks into the ophiolite zone is constrained to ~45 M...

A Visual Basic program for flexible, interactive processing of ion-microprobe data acquired for quantitative trace element, Al–Mg, Mn–Cr, Fe–Ni and U–Th–Pb geochronology applications is described. Default but editable run-tables enable software identification of secondary ion species analyzed and for characterization of the standard used. Counts obtained for each species may be displayed in plo...