Geologic Map of the Maysville Quadrangle, Chaffee County, Colorado
Geologic Map of the Maysville Quadrangle, Chaffee County, Colorado
Geologic Map of the Maysville Quadrangle, Chaffee County, Colorado
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valley near <strong>the</strong> eastern map boundary, between Walden Gulch and Blank Gulch. Soil at<br />
top is strongly developed. Partly equivalent to unit Qg3 <strong>of</strong> Van Alstine (1969) and<br />
correlated with <strong>the</strong> Kansan glacial stage <strong>of</strong> <strong>the</strong> Midwestern USA. Thickness probably<br />
more than 20 ft.<br />
Qk2 Kansan () alluvium, middle (middle Pleistocene) – Yellowish-gray to<br />
yellowish-orange, fairly well-stratified alluvium containing well-rounded to subrounded<br />
fragments <strong>of</strong> igneous and metamorphic rocks. <strong>Map</strong>ped only in <strong>the</strong> South Arkansas River<br />
valley near <strong>the</strong> eastern quadrangle boundary, between Walden Gulch and Blank Gulch.<br />
Soil at top is strongly developed. Partly equivalent to unit Qg3 <strong>of</strong> Van Alstine (1969) and<br />
correlated with <strong>the</strong> Kansan glacial stage <strong>of</strong> <strong>the</strong> Midwestern USA. Thickness probably<br />
more than 20 ft.<br />
Qk1 Kansan () alluvium, older (middle Pleistocene) – Yellowish-gray to yellowishorange,<br />
fairly well-stratified alluvium containing well-rounded to subrounded fragments<br />
<strong>of</strong> igneous and metamorphic rocks. Soil at top is strongly developed. Forms a terrace on<br />
<strong>the</strong> north side <strong>of</strong> <strong>the</strong> South Arkansas River 250 ft above stream level. Partly equivalent to<br />
unit Qg3 <strong>of</strong> Van Alstine (1969) and correlated with <strong>the</strong> Kansan glacial stage <strong>of</strong> <strong>the</strong><br />
Midwestern USA. Thickness probably more than 20 ft.<br />
Qna Nebraskan () alluvium, undivided (early Pleistocene) – Light-brown to gray,<br />
poorly sorted, poorly stratified, deeply wea<strong>the</strong>red, sandy bouldery gravel. Forms <strong>the</strong><br />
largest sections <strong>of</strong> high pediment surfaces on <strong>the</strong> range-front piedmont. Possibly includes<br />
outwash from pre-Bull Lake glaciers. Soil at top is strongly developed. Partly equivalent<br />
to unit Qg2 <strong>of</strong> Van Alstine (1969). Thickness possibly as much as 80 ft.<br />
Qna2 Nebraskan () alluvium, younger (early Pleistocene) – Light-brown to gray,<br />
poorly sorted, poorly stratified, deeply wea<strong>the</strong>red, sandy bouldery gravel. Forms <strong>the</strong><br />
youngest and most distal part <strong>of</strong> <strong>the</strong> high pediment surfaces on <strong>the</strong> range-front piedmont<br />
and is mapped only east <strong>of</strong> Walden Gulch. Possibly includes outwash from pre-Bull Lake<br />
glaciers. Soil at top is strongly developed. Partly equivalent to unit Qg2 <strong>of</strong> Van Alstine<br />
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