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Welcome to the blog for the Oberlin College Geomorphology Research Group. We are a diverse team of students working with Amanda Henck Schmidt on geomorphology questions. This blog is an archive of our thoughts about our research, field work travel notes, and student research projects. Amanda's home page is here.

Monday, February 16, 2015

Soil Pits Winter Term 2015



Soil Pits Site Descriptions & Analyses

CH-014 (Basin 35)


 


  •   CH-014 was collected from a riverbank. The O/A horizon is an organic-rich silt loam about 15cm deep. The B1 horizon (15-35cm) is very clayey, possesses a weak structure, and is between 30-40% gravel. The B2 horizon is 50-60% gravel. The flatland approaching the bank appears to be a grassy field with a few scattered small trees. The field slopes sharply towards the bank. The levels of 137Cs and 210Pbex exhibit fairly typical exponential-type decay with depth. The amount of 210Pbex decreases more quickly than the amount of 137Cs.


CH-015 (Basin 35)
   

  • The soil comprising CH-015 is a uniform, coffee-brown color throughout the column. The O/A horizon is a dark clay loam that is high in organics and is about 35cm thick. The B horizon is gravelly silt clay with 40-50% gravel and weak structure. This soil pit is located in a farm field. The amount of 137Cs and 210Pbex both increase between the 0-5cm section and the 5-10cm section, and drop off dramatically with increased depth. This pattern suggests that this area has experienced a change in erosion rates.



CH-028 (Basin 35)
  
 

  • CH-028 was collected on the ridge crest of a young coniferous forest. The first 4cm of soil is a grey silt loam that could be a less-developed forest A-horizon but may also be an erosional layer. The B1 horizon is a yellowish-brown silty clay soil with a well-developed blocky structure. The B2 horizon is a dark brown, sticky clay and has a well developed blocky structure. The soil profile contains low concentrations of 137Cs and 210Pbex and we only observe these isotopes in the upper 10cm of the soil. This suggests that the area has experienced significant erosion.


CH-029 (Basin 35)

  

  • CH-029 was collected from a fallow agricultural field that was probably forest at one time. The A horizon extends for about 30cm and is an olive-brown silt loam that contains some roots. The B horizon extends for another 30cm and is a yellowish brown silty clay. The horizons are separated by a whitish carbonate accumulation. The relatively uniform levels of 137Cs and 210Pbex throughout the soil profile indicate that the soil has been mixed by a plow.


CH-030 (Basin 35)