Physiographic Province

Surficial Geologic Material

Percentage of MFR Zones (%)

Southern Rocky Mountains

Glacial till sediments, mostly sandy, thin

2

Residual materials developed in sedimentary rocks, discontinuous

8

Alluvial sediments, thick

29

Residual materials developed in igneous and metamorphic rocks

61

Basin and Range

Eolian sediments, mostly dune sand, thin

7

Other surficial materials

11

Residual materials developed in igneous and metamorphic rocks

14

Alluvial sediments, thick

68

All MFR Zones

Eolian sediments, mostly dune sand, thin

6

Other surficial materials

10

Residual materials developed in igneous and metamorphic rocks

22

Alluvial sediments, thick

62