Data release for the geologic map of the Weldona 7.5' quadrangle, Morgan County, Colorado
The Weldona 7.5' quadrangle is located on the semiarid plains of
northeastern Colorado, along the South Platte River corridor where the
river has incised into Upper Cretaceous Pierre Shale. The Pierre Shale is
largely covered by surficial deposits that formed from alluvial, eolian,
and hillslope processes operating in concert with environmental changes
from the Pleistocene to the present. The South Platte River, originating
high in the Colorado Rocky Mountains, has played a major role in shaping
surficial geology in the map area, which is several tens of kilometers
downstream from where headwater tributaries join the river. Recurrent
glaciation (and deglaciation) of basin headwaters has affected river
discharge and sediment supply far downstream, influencing deposition of
alluvium and river incision in the Weldona quadrangle. During the
Pleistocene the course of the river within the map area shifted
progressively southward as it incised, and by late middle Pleistocene the
river was south of its present position, cutting and filling deep
paleochannels now covered by younger alluvium. The river shifted back to
the north during the late Pleistocene. Kiowa and Bijou Creeks are
unglaciated tributaries originating in the Colorado Piedmont east of the
Front Range that also have played a major role in shaping surficial
geology of the map area. Periodically during the late Pleistocene, major
flood events on these tributaries deposited large volumes of sediment at
their confluences, forming a broad, low-gradient fan of sidestream
alluvium that could have occasionally dammed the river for short periods
of time. Eolian sand deposits of the Sterling (north of river) and Fort
Morgan (south of river) dune fields cover much of the quadrangle and
record past episodes of sand mobilization during times of prolonged
drought. With the onset of irrigation and damming during historical
times, the South Platte River has changed from a broad, shallow, and
sandy braided river with highly variable seasonal discharge to a much
narrower, deeper river with braided-meandering transition morphology and
more uniform discharge.
Complete Metadata
| accessLevel | public |
|---|---|
| bureauCode |
[
"010:12"
]
|
| contactPoint |
{
"fn": "Margaret E. Berry",
"@type": "vcard:Contact",
"hasEmail": "mailto:meberry@usgs.gov"
}
|
| description | The Weldona 7.5' quadrangle is located on the semiarid plains of northeastern Colorado, along the South Platte River corridor where the river has incised into Upper Cretaceous Pierre Shale. The Pierre Shale is largely covered by surficial deposits that formed from alluvial, eolian, and hillslope processes operating in concert with environmental changes from the Pleistocene to the present. The South Platte River, originating high in the Colorado Rocky Mountains, has played a major role in shaping surficial geology in the map area, which is several tens of kilometers downstream from where headwater tributaries join the river. Recurrent glaciation (and deglaciation) of basin headwaters has affected river discharge and sediment supply far downstream, influencing deposition of alluvium and river incision in the Weldona quadrangle. During the Pleistocene the course of the river within the map area shifted progressively southward as it incised, and by late middle Pleistocene the river was south of its present position, cutting and filling deep paleochannels now covered by younger alluvium. The river shifted back to the north during the late Pleistocene. Kiowa and Bijou Creeks are unglaciated tributaries originating in the Colorado Piedmont east of the Front Range that also have played a major role in shaping surficial geology of the map area. Periodically during the late Pleistocene, major flood events on these tributaries deposited large volumes of sediment at their confluences, forming a broad, low-gradient fan of sidestream alluvium that could have occasionally dammed the river for short periods of time. Eolian sand deposits of the Sterling (north of river) and Fort Morgan (south of river) dune fields cover much of the quadrangle and record past episodes of sand mobilization during times of prolonged drought. With the onset of irrigation and damming during historical times, the South Platte River has changed from a broad, shallow, and sandy braided river with highly variable seasonal discharge to a much narrower, deeper river with braided-meandering transition morphology and more uniform discharge. |
| distribution |
[
{
"@type": "dcat:Distribution",
"title": "Digital Data",
"format": "XML",
"accessURL": "https://doi.org/10.5066/F7610Z63",
"mediaType": "application/http",
"description": "Landing page for access to the data"
},
{
"@type": "dcat:Distribution",
"title": "Original Metadata",
"format": "XML",
"mediaType": "text/xml",
"description": "The metadata original format",
"downloadURL": "https://data.usgs.gov/datacatalog/metadata/USGS.595290c8e4b062508e3c76db.xml"
}
]
|
| identifier | http://datainventory.doi.gov/id/dataset/USGS_595290c8e4b062508e3c76db |
| keyword |
[
"Bijou Creek",
"Bijou No 2 Reservoir",
"Broadway Alluvium",
"Bull Lake glaciation",
"Colorado",
"Cretaceous",
"Empire Reservoir",
"Fort Morgan",
"Front Range",
"Greeley",
"Holocene",
"Jackson Reservoir",
"Kersey",
"Kiowa Creek",
"Laramie Formation",
"Louviers Alluvium",
"Masters",
"Milliron Draw",
"Morgan County",
"OSL",
"Orchard",
"Pierre Shale",
"Pinedale glaciation",
"Piney Creek Alluvium",
"Pleistocene",
"Quaternary",
"Rocky Flats Alluvium",
"Slocum Alluvium",
"South Platte River",
"U-series",
"USA",
"USGS:595290c8e4b062508e3c76db",
"United States",
"Verdos Alluvium",
"Weld County",
"Weldona",
"Wildcat Creek",
"alluvium",
"argillic B horizon",
"braided",
"colluvium",
"discharge",
"dune",
"eolian",
"floodplain",
"geologic map",
"lignite",
"luminescence",
"meandering",
"radiocarbon",
"sand sheet",
"sheetflood",
"soil",
"terrace"
]
|
| modified | 2022-08-29T00:00:00Z |
| publisher |
{
"name": "U.S. Geological Survey",
"@type": "org:Organization"
}
|
| spatial | -104.00000, 40.25000, -103.87500, 40.37500 |
| theme |
[
"Geospatial"
]
|
| title | Data release for the geologic map of the Weldona 7.5' quadrangle, Morgan County, Colorado |
