Changes

The Plainview and Lytle sandstones (transgressive shallow marine and fluvial, respectively) have been described in the outcrop west of Wattenberg Field by MacKenzie<ref name=MacK1971> MacKenzie, D. B., 1971, Post-Lytle Dakota Group on west flank of Denver basin, Colorado: The Mountain Geologist, v. 8, p. 91–131.</ref>, Weimer<ref name=Weimer1996 />, and others. [[:file:M125-WattenbergField-Figure9.jpg|Figure 9]] illustrates that this interval ranges in thickness from 100 to 140 ft in the mapped area. The Lytle contains interbedded sandstone and conglomeratic sandstone. The Lytle is 50–100 ft thick in the outcrop and consists of 60%–80% sandstone and 20%–40% mudstone<ref name=MacK1971 />. Cross stratification is common in the sandstone beds. Mudstones are greenish gray to maroon. The sandstones and mudstones do not contain tracks, trails, or burrows. The basal contact with the Morrison is a scour surface and is placed at a lower thick sandstone. The thick sandstones are interpreted as nonmarine channel sands in a large alluvial plain environment. Porosities on logs range from 8% to 12%.

The Plainview and Lytle sandstones (transgressive shallow marine and fluvial, respectively) have been described in the outcrop west of Wattenberg Field by MacKenzie<ref name=MacK1971> MacKenzie, D. B., 1971, Post-Lytle Dakota Group on west flank of Denver basin, Colorado: The Mountain Geologist, v. 8, p. 91–131.</ref>, Weimer<ref name=Weimer1996 />, and others. [[:file:M125-WattenbergField-Figure9.jpg|Figure 9]] illustrates that this interval ranges in thickness from 100 to 140 ft in the mapped area. The Lytle contains interbedded sandstone and conglomeratic sandstone. The Lytle is 50–100 ft thick in the outcrop and consists of 60%–80% sandstone and 20%–40% mudstone<ref name=MacK1971 />. Cross stratification is common in the sandstone beds. Mudstones are greenish gray to maroon. The sandstones and mudstones do not contain tracks, trails, or burrows. The basal contact with the Morrison is a scour surface and is placed at a lower thick sandstone. The thick sandstones are interpreted as nonmarine channel sands in a large alluvial plain environment. Porosities on logs range from 8% to 12%.

[[file:M125-WattenbergField-Figure9.jpg|center|framed|300 px|{{Figure number|9}}(A) Isopach Plainview/Lytle sandstone interval. Also shown are wells that produce from Plainview/Lytle. Unit ranges in thickness from 100 to 140 ft in mapped area. Contour interval 20 ft. (B) Well log illustrating Plainview/Lytle section and perforated interval. Initial production for the well was 343 MCF and 6 BOPD. Location of well is the red circle on [[:file:M125-WattenbergField-Figure9.jpg|Figure 9A]].

[[file:M125-WattenbergField-Figure9.jpg|center|framed|300 px|{{Figure number|9}}(A) Isopach Plainview/Lytle sandstone interval. Also shown are wells that produce from Plainview/Lytle. Unit ranges in thickness from 100 to 140 ft in mapped area. Contour interval 20 ft. (B) Well log illustrating Plainview/Lytle section and perforated interval. Initial production for the well was 343 MCF and 6 BOPD. Location of well is the red circle on [[:file:M125-WattenbergField-Figure9.jpg|Figure 9A]].]]

The top of the Lytle is a transgressive disconformity. The Plainview consists of very fine- to fine-grained sandstones and clay matrix. Ripple stratification and burrowing is common. The upper contact with the Skull Creek Shale is gradational into shale. The Plainview is interpreted to be a transgressive shallow-marine deposit. Porosities on logs are less than 10%.

The top of the Lytle is a transgressive disconformity. The Plainview consists of very fine- to fine-grained sandstones and clay matrix. Ripple stratification and burrowing is common. The upper contact with the Skull Creek Shale is gradational into shale. The Plainview is interpreted to be a transgressive shallow-marine deposit. Porosities on logs are less than 10%.