Marine sandstone and siltstone

Unit symbol: Kmss
Age range Cretaceous, Cenomanian to Albian (113 to 93.9 Ma)
Lithology: Sedimentary
Group name: Marine sandstone and siltstone
Shallow marine deposits along the Yukon River and in a belt to the west extending from the southern edge of the Norton Bay quadrangle to the western Kateel River quadrangle consist of fine- to coarse-grained, crossbedded, lenticular sandstone grading down into fine-grained sandstone and interbedded dark-gray siltstone and shale (Patton and others, 2009). In the belt to the west, unit is composed predominantly of siltstone and shale. These shallow marine deposits contain an abundant molluscan fauna of late Early (Albian) and early Late (Cenomanian) Cretaceous age

Source map information

Source map Wilson, F.H., Labay, K.A., Shew, Nora, and Mohadjer, Solmaz, 2005, Digital datasets for geologic map by Patton, W.W., Jr., Wilson, F.H., Labay, K.A., and, Shew, Nora: Preliminary Integrated Geologic Map Databases for the United States: Digital Data for the Reconnaissance Geologic Map for the Yukon-Koyukuk Basin, Alaska: U. S. Geological Survey Open-File Report 2005-1341, on-line only.
Symbol Kms
Unit name Fluvial and shallow marine sandstone and shale, undivided
Description The shallow marine deposits in the lower part of the unit Ks are mapped separately along the Yukon River and in a belt to the west extending from the southern edge of the Norton Bay quadrangle to the western Kateel River quadrangle. These deposits compose a marine tongue that underlies the fluvial deposits and thickens westward. On the Yukon River, the marine deposits consist of fine- to coarse-grained, crossbedded, lenticular sandstone grading down into fine-grained sandstone and interbedded dark-gray siltstone and shale. In the belt to the west, the marine deposits are composed predominantly of siltstone and shale.
Lithology Unconsolidated

Correlated geologic units

Label Ksse
Description Marine sandstone and siltstone, Early Cretaceous
Geologic age Albian to Cenomanian
Geologic setting Sedimentary, deltaic-and-nearshore
Lithology Form Importance
Shale < Mudstone < Clastic < Sedimentary Bed Major
Siltstone < Clastic < Sedimentary Bed Major
Sandstone < Clastic < Sedimentary Bed Minor