Laserfiche WebLink
Wildcat Mining Corporation Page 22 <br />i <br />Stratigraphy of the May Day Mine Area <br />Morrison formation. Consists of upper Brushy Creek member bentonitic <br />_ <br />mudstone and lower Salt Wash member interbedded fine- grained gray <br />sandstone and green -gray mudstone. The unit does not host ore. <br />Junction Creek Sandstone. Light -gray to tan, highly cross - bedded to massive, fine- to <br />coarse -grained eolian sandstone. <br />Wanakah Formation. Consists of two members. This upper marl member is mostly white <br />to tannish to - reddish colored, fine-grained sandstone, mudstone, and marl. <br />pale <br />- -- . - - -, - -- - -•. - Pony Express Limestone member consists of medium - to dark -gray, very thin - bedded <br />.... <br />to laminated, micritic and algal limestone. The Pony Express member is locally <br />brecciated intruded by sand dikes and is a preferred host for mine ralization. / <br />Entrada formation. Light -gray to white, fine- to coarse - grained highly cross - bedded <br />sandstone. The Entrada sandstone frequently has prominent large -scale cross-bedding. <br />• <br />— Dolores formation. Mostly dark—red—brown to purple brown shale and siltstone and brown, <br />— — gray, and red -brown lenticular sandstone and limestone - pebble conglomerate. <br />Diorite Porphyry – Cretaceous - Paleocene. Light -gray monzonite- diorite <br />_. �. dikes and sills <br />Figure 5. Stratigraphy of the May Day Mine area. <br />Igneous Rocks <br />The igneous rocks of the La Plata Mountains are of Late Cretaceous or Tertiary <br />age and are all intrusive. They vary widely in composition and form, but all of <br />them can be grouped in two general types. The porphyritic rocks, which are the <br />more abundant, occur as stocks, sills, and dikes of diorite to monzonite <br />composition. The nonporphyritic rocks, which are in general younger than the <br />porphyries, consist of syenite, monzonite and diorite and occur mostly as <br />irregular stocks. The porphyritic bodies were intruded forcibly between the layers <br />of sedimentary rock and were a major factor in the uplift of the La Plata dome, <br />• whereas the nonporphyritic rocks cut across the sedimentary formations and <br />January 2007 May Day — Idaho Mine Colorado <br />