Sample: |
Sample No. 92AD33-91 -- USGS No. 32436-PC
|
Locality: |
Field No. 92AD33-91
|
Description: |
Howard Pass C-3. Measured section extends from 68o 30'40"/157o 31'00" (top) to 68o 30'32"/157o 31'34" (base). Sample from 30 cm x 2 m-long lens of dolostone within chert that has crinoidal-skeletal packstone-grainstone texture. Thin section is dolomite crystal mosaic that contains a chert lens displaying relict bioclasts (chiefly crinoid ossicles). Collected 91 m below top of measured section. Heavy-mineral concentrate is chiefly fluorite. (description from Dover et al., 2004, p. 42 (Table 1)). [Howard Pass C-3. 68°30'43", 157°31'00". 30 cm x 2 m-long lens of dolostone within chert with crinoidal-skeletal packstone-grainstone texture. Collected from 91.2 m below top of measured section. 92AD32, 33, 49A, 47 from platformal facies of Lisburne Group at Mt. Bupto, ~1-2 miles east of headwaters of Bushy Creek and ~4 miles southwest of Rim Butte along west side of eastern half of Mount Bupto, western Brooks Range. 92AD32A collected from "Black Lisburne" facies, overlying (structurally and stratigraphically(?) rest of the samples (92AD33, 49, 47). Age of similar rocks at Ivotuk Hills is Chesterian (85ASi14-18). 92AD33-0.2 to -120 from 1240 m and 1100 m elevation of continuously exposed chert and dolostone along trend with measured section of Gus Armstong (<0.25 mile due north), who suggested an age of Meramecian (based on silicified colonial corals and forams) for the upper 100 m (at least) of section (see Armstrong, AAPG Bulletin, v. 54, p. 251+, 1970); N part NE1/4 sec. 9, T. 11 S., R. 24 W, lat. 68°30'43" to 68°30'37", long. 157°31'00" to 20", Howard Pass C-3 quadrangle. (description from Harris E&R report dated March 17, 1995)] |
Location: |
Alaska Quadrangle: Howard Pass C-3 Township&Range: 11 S. 24 W. Section: 9 Lat.: 68o30'43 " Long.: 157o31'00 " |
|
|
Reference
|
|
|
Title: |
Report on Referred Fossils
,
1995
(03/17)
|
|
Analysis of all samples is given in the accompanying 16-page table. The range of biostratigraphically important samples is shown on the accompanying diagram. The heavy-mineral concentrates were analyzed by Nancy Stamm; the residues have been returned to Julie Dumoulin. Please note a few (~4 samples have heavy-mineral concentrates that include chalcopyrite and bornite). |
Report by: |
Anita G. Harris
|
Referred by: |
Julie A. Dumoulin
,
J. H. Dover
|
|
|
| Age: | Osagean (middle-late Osagean) |
Formation: | Lisburne Group |
CAI: | Min: 1.5 |
|
|
|
|
Comment: | Age: S. anchoralis-D. latus Zone through the lower Po. mehli-Lower G. texanus Zone (middle-late Osagean). Biofacies: Postmortem transport from the kladognathid biofacies; eotaphrids are shallow-water, high-energy forms so that this collection suggests proximity to a high-energy depositional regime. CAI = 1.5 7.5 kg or cok processed (620 g +mesh and 425 g 20-200 mesh insoluble residue). Heavy-mineral concentrate: chiefly fluorite, lesser dolomite rhombs and iron oxides. |
|
|
|
|