Rapid decomposition of geological samples by ammonium bifluoride (NH HF ) for combined Hf-Nd-Sr isotope analyses.

Rationale: Complete decomposition of silicate rock matrices is crucial in determining their isotopic compositions, but acid dissolution in a high-pressure steel-jacketed bomb, which has been the only powerful, effective technique thus far, is time-consuming and expensive. Rock dissolution using ammonium bifluoride (ABF), as described here, is a viable alternative.

Methods: Geological reference materials (GRMs) were digested using ABF in closed Teflon beakers at temperatures of 220/230°C in a convection oven and subsequently treated with HNO .

Mars-Relevant Field Experiences in Morocco: The Importance of Spatial Scales and Subsurface Exploration.

During field work at the Ibn Battuta Mars analogue sites, two research questions were analyzed: (1) How do we identify sampling sites using remote and local imaging and (2) what kind of information can be gained from shallow subsurface exploration? While remote images help in targeting field activities in general, the connection between observations at different spatial scales for different rocky desert terrain types is not well established; in this, focused comparison of remote in situ images of well-selected analogues would help a great deal. Dried up lake beds as discerned in remotely acquired data may not show signatures of past water activity, while shallow subsurface exploration could reveal the lacustrine period. Acquisition of several satellite images of the same terrain under different geometries would help to support the planning of such in situ work.