Laserfiche WebLink
suggest an erosional channel in the bedrock surface that was subsegaendy filled by unconsolidated <br />deposits. It is likely that this channel was formed by meltwater during the last glaciation and became <br />a tributary to the ancestral Mississippi River. It was subaequen[ly tilled by glacial deposits.'I'he <br />preponderance of sand and gravel in Elk River suggests that the till material is Iikcly glacial outwash <br />deposits (sand and gravel). The thickest surficial deposits (i.e. the greatest depth to bedrock) shown <br />~,, .. <br />~ ~ ~ ~ <br />~~ c <br />4, rg f i t a ~ - f ~ , ~~ & .. <br />t'~ < . q . <br />yP $.~ 1 y..Y l~~ .f} <br />+" `.. ~ ~ V <br />, RVi. T"" ~ ~ ~ti <br />'x~o- ~ a 'n3 F is~ , ~. <br />yy ~., 4S <br />~j 3 t <br />} , we f + <br />+? .~ ... r~•~*.-fie, A~~.'~i .r .... ~ .~ ~. <br />X ~ '~ RNA e J ~ ~ <br />~~ „~~a ~• t,~ ~ <br />I` .' ~, ~ , , , <br />r r <br />° ` ~ ~ <br />~ <br /> <br />A <br />ll <br />A <br />d <br /> ~. ~ ~' , ; ,~ <br />~ rea <br />y <br />verage <br />:E ; ~ <br />' ~ =- Percent Sand <br /> <br />~{ <br />`gc. • - <br />'. nk `~ ;' <br />'~.~" : ` !^:~ • <br />0- 3 712 <br />r <br />Y <br />~ <br />j <br /> <br />} <br />~' <br />,,,~ '~, ~. ~: Y <br /> <br /> <br />..' <br /> <br /> <br />'~- <br /> <br /> <br />9712 19425 <br />a i' ti <br />~ ~ 9egp + T <br />1' 7 <br />"~~ ~ ~ F 4 i <br />19 425 - 29.137 <br />~ <br />". ~~ r <br />.'~ e~.,. ~ -~ *' ; <br />7 ~ 29 137 -38 86 <br />{ ~ ~ ' ~ ~ ~ '~` 1 ~ 3B 85..98 562 <br />Y ~f <br />a. <br />r' j~ <br />- <br />' <br />• a- x <br />- <br />' <br /> <br />48 562 58 275 <br />R <br />-„ e <br />~V -, <br />C~ 58 PS 67 987 <br />2 fl 2 4 Miles '~ ~ -- • ' <br />, ~ 67 9s~ - n ~ <br />^ ~~ .,. <br />' ~, <br />~. ~. L - ~J ni-s~ar2 <br />- - --- <br />Figure 5 Aerially Averaged Pe rcentage of Sand or Gravel in Unconsolidate d Deposits <br />on Figure 4 corresponds approximately to the areas where the Eau Claire Formation has been eroded <br />away and the first bedrock unit is Che Mt. Simon-Hinckley Formations, ash shown on E'igure 3. <br />Unconsolidated glacial drift deposits are typically heterogeneous. in one location, the unconsolidated <br />deposits can be mostly sand or gravel and in a nearby location, only clay may be found. These abrupt <br />changes from sand to clay in glacial deposits makes siting wells difficult in some locations because it <br />is difficult to predict how much water a well in these deposits might yield. Using the Minnesota <br />P:AMplsA23 MNV71A2771 105 Water Supply ~Vtunative Study\FinalDelfvecabiesVAI[erna[ives Rapo~t_final.doc 9 <br />