A Proposed Amphibolite Reference Rock Sample (AM-H) from Himachal Pradesh

An amphibolite sample named as AM-H is the third candidate reference rock in the series of reference samples from Himalaya. First two geostandards already characterized in the series being MB-H (metabasic) and DG-H (granite), are now in use for routine analysis at several laboratories. The sample is being distributed to several participating laboratories and analysts for contribution of analytical data. The sample was tested for its suitability as a reference standard in terms of its bulk homogeneity using F-test carried out for 16 fractions of the sample analyzed in duplicate. The results of homogeneity test along with relevant information like, location, geological set-up, mineralogical makeup, petrography and expected chemical composition are given for the benefit of potential analyst/contributors. The proposed reference sample may prove useful for analysis of metabasics and intermediate igneous rocks with high Cr and lower abundances of elements like Ba, Na, K, P, Nb and Zr.