WYOMING ROCKIES 



367 



■ing Fort Union time; and a well-defined syncline north of the Washakie Range 

 ,:was drained by streams flowing from the west across the present site of the 

 .Absaroka Range. 



v The second pulsation of the Laramide orogeny came at the close of Fort 

 -Union time. The intensity and extent of folding and faulting are not known. 

 -"During this and the preceding movement, the major structures of the Washakie 

 Range developed. 



Then followed the deposition of 1000 feet or more of early lower Eocene 



rocks (Indian Meadows) on a surface of high relief. The third pulsation of the 



Laramide orogeny is believed to have occurred at this time, and the klippen 



south of Coulee Mesa may be remnants of a thrust sheet pushed southward into 



.the basin. 



The fourth pulsation of the Laramide orogeny caused gentle folding along 

 the northeastern flank of the Wind River Mountains. The early lower Eocene 

 strata were eroded in places, and a broad southeastward-trending valley was 

 .'formed between the Wind River and Washakie ranges. 



Following this cycle of erosion, 500 feet of late lower Eocene rocks (Wind 

 River) were deposited in this valley. 



The fifth pulsation of the Laramide orogeny caused folding and thrust fault- 

 ring along the center of the syncline between the Washakie and Wind River 

 ranges. This was followed by the deposition of 1000 feet of middle Eocene 

 rocks (Aycross) and the beginning of active Cenozoic volcanism in the general 

 Absarokan region. Acidic and andesitic volcanic and pyroclastic rocks dominate. 

 The sixth pulsation of the Laramide orogeny resulted in gende localized fold- 

 ing and some erosion after the close of middle Eocene time. 



Deposition of 3000 feet of Oligocene (?) pyroclastic rocks (Wiggins), in- 

 trusion of plugs, extrusion of flows, and climax of Cenozoic volcanism. Acidic 

 andesites dominate. Washakie and Owl Creek ranges were completely buried; 

 jWind River and Righorn basins were filled; Wind River and Righorn ranges 

 were partially buried. 



The eighth pulsation of the Laramide orogeny caused folding in localized 

 ! areas, recurrent uplift along parts of the buried Washakie Range, and erosion. 

 Intrusion of dacite plugs and extrusion of flows followed. 



The cross section of Fig. 24.6 shows some of the above relations. 



HEART MOUNTAIN AND RELATED FEATURES 



South of the Precambrian mass of the Beartooth Range and lying 

 along the east front of the Absaroka Mountains are a number of relatively 

 smaller features made up dominantly of Paleozoic limestones and dolo- 

 mites. See Fig. 24.7. The anticlines known as Pat O'Hara and Rattlesnake 



CE 



:" 



SOUTHERN WIND 



RIVER BASIN 



AND 



BEAVER DIVIDE 



DUNCAN 

 AREA 



BIGHORN 

 BASIN 



BRIOGEft 

 BASIN 



WASHAKIE 

 BASIN 



UINTA 



BASIN 



O 



o 



Q. 



3 



2 





wtogins 



formation 

 1 











a 

 o 



i 



S 



Beds «ith 

 lo»er Brule 



fauna 



a. 

 o 



| 



Beds with 

 Ghadron 

 -> fauno 



? 



or uj 

 O z 



Ho 



o ° 

 O -1 



I 



Beds with 



Duchesne Riv. 



fauna 











S 



£ 



Lopo-M 



HtjIftlOy 



■ 



z 

 o 



<L 



a. 



3 



•3 



Beds with 

 Uinta 



fauna 



Tepee Troll 



formation 









3 



c 



iT>#mbt' 



1 



Tl 



B 



Woshofci* 



fofmoton 



of 



Gfonger 



B 



Wogon- 

 hountt 



lo"T»oi>on 



a 

 a 



I 



Green Cove 



formotion of 



Wood 



Aycross 

 formotion 



Tolmon 

 formotion 



D 



c 



Twin Bulles 



member 



A 



G'ten Ri.er 

 fofmo'ton 



B 

 A 



Blocks For* 

 member ^ 



G 



etn Rivtr fn 





Cathadroi Bluffs 

 -j tongue of 

 ^"^---^Wosatch 



Hiowatha W«ftibif 

 Wotaich 



a: 



* 



o 



< 



S 



E 

 cr 

 S 



Beds with 



Lost Cabin 



founo 



Wind River 

 formotion 





Beds with 



Lost Cabin 



founo 



Tipton longut of 

 Gr«tn R.vir fm 



Beds with 

 Lysife founo 



Beds with 

 Lysile founo 







Wotaich 





Indian Meadows 

 formotion 



Beds with 



Grey Bull 



founo 











f 



'- c- Ci 



Fig. 24.5. Correlation chart of. the lower Tertiary formations of south-central Wyoming and the 

 Uinta basin in Utah. After Tourtelot and Nace, 1946. 



Mountains, and Logan Mountain and Sheep Mountain are prominent. 

 Two remnants of Paleozoic strata, Heart Mountain and McCulloch Peaks, 

 consisting of large, irregularly disposed blocks rest on the Eocene Will- 

 wood formation. Heart Mountain is in the Rig Horn basin at least 12 miles 

 east of any possible root area, and McCulloch Peaks is over 2S miles. 

 How these relatively small masses got where they are has proved a real 

 mystery, and considerable has been written about them. Pierce ( 1941 and 

 1957) summarized the previous views and presented his own interpro- 



