Our Changing Landscape-From Sea Floor to Mountain Top

Our Changing Landscape-From Sea Floor to Mountain Top (HMV9C)

Location: Golden, CO 80401 Jefferson County
Country: United States of America

N 39° 44.025', W 105° 14.335'

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·Colorado's geologic history dates back nearly two billion years. Several mountain ranges have been uplifted and eroded away before the rise of today's Rocky Mountains. The landscape you see in front of you has undergone many dramatic changes. This story starts at a billion years ago.

·The sea covers Colorado: 80 million years ago. Today's Rocky Mountains did not exist. Where you are standing and all before you was beneath a shallow sea that covered the middle of the North American continent. Today, marine fossils are found in the sediments deposited at that time (Pierre Formation).·Sea retreats as mountains begin to rise dinosaurs leave footprints near subtropical coal swamps: 68 million years ago. As the seas withdrew, sand, mud, and clay were deposited near the shore (Fox Hills Formation). Coal formed near rivers in swamps (Laramie Formation). The environment was warm with ample rainfall. These sedimentary rocks now lie beneath the City of Golden. You can see dinosaur tracks and large leaf fossils in the Laramie Formation along the Triceratops Trail in Golden (see other sign).

·The mountains form highest 60-68 million years ago. Volcanic eruptions occur 64 million years ago. Uplift of the Laramide Rocky Mountains began about 68 million years ago. Rock fragments from the newly raised mountains are found in the sediments exposed in the Golden area (Arapahoe and Denver Formations.) 64 million yeas ago, lava covered the area forming the rock now at the top of the Table Mountains. The source of the lava was Ralston Dike north of Golden (see other sign).

·The Rockies today: 63 million to the present. During that time period, the Laramide mountains were eroded and the rock debris was deposited on the plains about to the level where you are standing on Lookout Mountain. Later, rivers from the high mountains cut deep canyons such as Clear Creek canyon. Along the mountain front, the softer rocks were eroded leaving the hard rock as Dakota Hogback, the Table Mountains, and the rocks under your feet.

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HM NumberHMV9C
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Marker ConditionNo reports yet
Date Added Friday, September 5th, 2014 at 9:17am PDT -07:00
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Locationbig map
UTM (WGS84 Datum)13S E 479527 N 4398234
Decimal Degrees39.73375000, -105.23891667
Degrees and Decimal MinutesN 39° 44.025', W 105° 14.335'
Degrees, Minutes and Seconds39° 44' 1.50" N, 105° 14' 20.10" W
Driving DirectionsGoogle Maps
Area Code(s)303, 720
Closest Postal AddressAt or near 114-198 Buffalo Bill Trail, Golden CO 80401, US
Alternative Maps Google Maps, MapQuest, Bing Maps, Yahoo Maps, MSR Maps, OpenCycleMap, MyTopo Maps, OpenStreetMap

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