Laserfiche WebLink
pitsdinewhichnUnit832wae encounteredk�theseteedimenteiextendedrbelow <br /> the termination depth of the explorations (8 to 12 feet beloW <br /> exieting ground surface) . <br /> Unit 4 (fill) wae observed in EP-1, EP-3. Ep'4� and EP-ti through EP- <br /> 12. Theee sedimenta varied in coapo81fine to tcoarlse sandraand <br /> 1 composed of loose , moiat , brown, eilty, <br /> fine to medium eand with gravele, and loose t� medium denee, moiet, <br /> saturatfinento�coarseesand rwith tec ttereU gravelsalcoY�� eeiland <br /> peaty, <br /> unitaeTThesenaedimente were obeerved over YingM both Unitv 2 and Unit <br /> 3 depoaite. In EP-3, the lower cont�o the teouth tand eaet.9 a��d Unit <br /> 2 sediments was noted to be dipping <br /> 3_2 Geoloaic Histor <br /> The geologic hietory of the Puget Sound region in the laet 12 ,500 to <br /> 2,000,000 yeare hae been a ae4uence of thie narea wae theTVashon age <br /> sheete. The laet ice sheet to occupy <br /> depoaita �enco n�t red during t hiea studyf Were deposited durinqt this <br /> qlacial event. <br /> Unit 1 sedimente are interPreted to be Vashon advance outwaeh <br /> depoaite. These aedimenta are glacadvancinq V ehon aqe glaciereby <br /> depoaited in front of the southerly <br /> glacial-marginal etreame. <br /> Unit 2 eedimente were subsequently depoeited atop the Vashon advance <br /> outwaeh deposits (Unit 11 . Unit 2 is interpreted to be Vaehon <br /> lodgement t111 ahich wae depoeited at the eole of the advancinq <br /> Vashon age gla88Veral thoueandifeet ofaice whichbh en reeult dlin <br /> coneolidated by <br /> their denae to very denee condition. <br /> Unit 3 eediment� are in depoeited by the melting�of aediment laden <br /> materials were app�:rently <br /> sedimente9have not beei� coneolidat d byeoverridinq gl ci 1 ice,Theee <br /> Unit 4 is considerecl to be fill a arentlyaplaced to backfillla <br /> placedl . Theee fill soile were app <br /> natural depression in th�� central portion acroee theeait u and may <br /> fill soils uere also obeerved intermittently <br /> represent a second episode of fill placement. ah uti ity btrench or <br /> EP-3 may have been the reault of backfilling <br /> from previous aubeurface exploratione of the eite. Placement and <br /> muetabeiunderetoodithatmthernatureeandnextentuofnsuch materiaie� are <br /> uncertain and unpredictable. <br /> 4 <br /> � <br />