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Lakes in the Bonneville basin have fl uctuated dramatically in response to changes in rainfall, temperature, and drainage diversion during the Quaternary. We analyzed tufas and shells from shorelines of known ages in order to develop a relation between 87 Sr/ 86 Sr ratio of carbonates and lake level, which then can be used as a basis for constraining lake level from similar analyses on carbonates in cores. Carbonates from the late Quaternary shorelines yield the following average 87 Sr/ 86 Sr ratios: 0.71173 for the Stansbury shoreline (22-20 14 C ka; 1350 m), 0.71153 for the Bonneville shoreline (15.5-14.5 14 C ka; 1550 m), 0.71175 for the Provo shoreline (14.4-14.0 14 C ka; 1450 m), 0.71244 for the Gilbert shoreline (~10.3-10.9 14 C ka; 1300 m), and 0.71469 for the modern Great Salt Lake (1280 m). These analyses show that the 87 Sr/ 86Sr ratio of lacustrine carbonates changes substantially at low-to mid-lake levels but is invariant at mid-to high-lake levels.Sr-isotope mixing models of Great Salt Lake and the Bonneville paleolake system were constructed to explain these variations in 87 Sr/ 86 Sr ratios with change in lake level. Our model of the Bonneville system produced a 87 Sr/ 86 Sr ratio of 0.71193, very close to the observed ratios from high-shoreline tufa and shell. The model verifi es that the integration of the southern Sevier and Beaver rivers with the Bear and others rivers in the north is responsible for the lower 87 Sr/ 86 Sr ratios in Lake Bonneville compared to the modern Great Salt Lake. We also modeled the 87 Sr/ 86 Sr ratio of Lake Bonneville with the upper Bear River diverted into the Snake River basin and obtained an 87 Sr/ 86 Sr ratio of 0.71414. Coincidentally, this ratio is close to the observed ratio for Great Salt Lake of 0.71469. This means that 87 Sr/ 86 Sr ratios of >0.714 for carbonate can be produced by climatically induced low-lake conditions or by diversion of the upper Bear River out of the Bonneville basin. This model result also demonstrates that the upper Bear River had to be fl owing into the Bonneville basin during highstands of other late Quaternary lake cycles: carbonates from the Little Valley (130-160 ka) and Cutler Dam (59 ± 5 ka) lake cycles returned 87 Sr/ 86 Sr ratios of 0.71166 and 0.71207, respectively, and are too low to be produced by a lake without the upper Bear River input.

We present two new modalities for generating chemical maps. Both are mid-IR based and aimed at the biomedical community, but they differ substantially in their technological readiness. The first, so-called "Digistain", is a technologically mature "locked down" way of acquiring diffraction-limited chemical images of human cancer biopsy tissue. Although it is less flexible than conventional methods of acquiring IR images, this is an intentional, and key, design feature. It allows it to be used, on a routine basis, by clinical personnel themselves. It is in the process of a full clinical evaluation and the philosophy behind the approach is discussed. The second modality is a very new, probe-based "s-SNOM", which we are developing in conjunction with a new family of tunable "Quantum Cascade Laser" (QCL) diode lasers. Although in its infancy, this instrument can already deliver ultra-detailed chemical images whose spatial resolutions beat the normal diffraction limit by a factor of ∼1000. This is easily enough to generate chemical maps of the insides of single cells for the first time, and a range of new possible scientific applications are explored.