Mary's Frog Pond Botanical Area 



Climatic setting. The net annual precipitation balance for Mary's 

 Frog Pond (from the MAPS database) is 20 inches, placing this 

 sampling site among the five moist high-elevation sites in the data 

 set. None of the NOAA climatic stations provide data particularly 

 applicable to the Mary's Frog Pond site; Lolo Hot Springs, the 

 nearest climatic station, is at a considerable lower elevation and 

 has a sporadic recent record. Mean monthly precipitation at the 

 Lolo Hot Springs Station shows a bimodal distribution, with a 

 January maximum and a secondary June peak. Regionally, 

 precipitation totals in 1993 were above average and in 1994 (the 

 year of the DHES sampling) were below average. 



Geologic setting. Mary's Frog Pond is underlain by the Ravalli 

 Group of the Proterozoic-aged Belt series. The intrusive contact 

 of the Idaho Batholith is very nearby, however, and mineralization 

 presumably related to hydrothermal intrusive processes occurs in 

 the immediate vicinity. Surficial deposits in the area are 

 apparently undescribed, and the origins of the pond basin are 

 unclear from the available information. One source describes the 

 pond as a "glacial scour" , but there is no supporting documentation 

 given for this interpretation, and the drainage in which the pond 

 lies does not have obvious glacial landforms. 



Hydrologic type. Mary's Frog Pond is a small, internally drained 

 depression of uncertain origin, which lacks both surface water 

 inflow and outflow at the water levels observed during sampling. 



Basin characteristic. Mary's Frog Pond has a small, steep surface 

 water catchment and a catchment to wetland area ratio which ranks 

 low among Rocky Mountain sites. The depth of the pond is unknown. 

 Given the setting in an area of high net precipitation, the pond 

 is inferred to discharge either via ground-water or by unmapped 

 surface-water outflow (or both). Surface features within the 

 wetland catchment include a portion of an access road to the 

 abandoned Ward Lode mine. 



Water chemistry. Mary's Frog Pond contains extremely dilute, 

 somewhat acidic water with sodium and potassium in excess of 

 calcium and magnesium. The anion distribution is uncertain due to 

 the dilute nature of the water. Mineral eguilibria indicate highly 

 undersaturrated conditions with respect to carbonate phases; 

 saturation indices are not quantitatively meaningful, however, due 

 to the large charge balance error in the analysis. 



Nutrient concentrations are very low; ammonium and nitrate 

 concentrations were below reporting limits, and orthophosphate and 

 total phosphorous concentrations were at or near the lower end of 

 the ranges for the entire sample set. The total organic carbon 

 concentration was also relatively low. 



With the exception of aluminum, iron, and silica (all reported at 



