ROCK GLACIERS, EMMA, NITRATE, MICROBES Mark Williams and others 2006 and 2007

DROUGHT CONDITIONS

SURFACE TEMPS: RG5

SOLUTE CHEMISTRY

MULTI-YEAR

 18 O: large changes

Local Meteoric Water Line No evaporation Melt- Freeze Cycles

POTENTIAL END-MEMBERS

PCA ANALYSIS

FLOWPATHS

Model Validation

NITRATE AND MICROBES

NUTRIENTS

RG5: MULTIYEAR

SYNOPTIC COMPARISON

N SOURCES USING EMMA

FLUORESENCE PROPERTIES

MICROBIAL SIGNATURE?

The Internal Structure and Hydrologic Flowpaths of the Green Lake 5 Rock Glacier, Colorado Front Range, USA Leopold M, Williams MW, Caine N, V oe lkel J, Dethier D (in press)

Here we evaluate the conceptual model of RG5 by Williams et al. (2006) using geophysical techniques. We develop an independent model of the structure of the same rock glacier that Williams et al studied using three separate geophysical techniques: –shallow seismic refraction (SSR); –ground penetrating radar (GPR); and –electric resistivity tomography (ERT). In a second step we compare the two different models and discuss the consequences for future hydrological studies.

Image of RG5-GPR-1 after application of the filter sequence and topography correction in the upper part and an outline of the most prominent reflections at the lower part of the figure. Note the prominent reflection of the valley floor contact at the base of the 50 MHz-GPR image. TWT = two way travel time.

Inversion results of ERT-images at RG5 with RG5-ERT-1 (a) and RG5-ERT-2 (b). RG5-ERT-3 (c) and RG5-ERT-4 (d) are lines that were surveyed in front of the lobe. Note the different resistance classification for the same color pattern in all images! Red is ice White is an air pocket

Chemistry works!