| Sample: |
Sample No. 92AD30B -- USGS No. 11949-SD, also 12463-SD
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| Locality: |
Field No. 92AD30B
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| Description: |
Sample collected on E-W segment of ridge. Partly silicified brachiopod lime packstone. (description from Blodgett E&R report of 5/3/94)[Howard Pass B-5. Lat. 68o 29'43" N., Long. 158o 34'00" W. Partly silicified brachiopod packstone. Thin section is brachiopod packstone containing crinoid ossicles and gastropods; many bioclasts silicified and matrix largely dolomitized. Collected from unnamed Devonian limestone, about 10 m above 92AD28A-4. Brachiopods of early Eifelian age collected from this locality (see table 3). Heavy-mineral concentrate includes 7 gastropod, 1 ostracode, and 3 tentaculitid phosphatized steinkerns. (description from Dover et al., 2004, p. 45 (Table 1))]; [Howard Pass B-5. 68°29'45", 158°35'10". Partly silicified brachiopod packstone. Collected from unnamed Devonian limestone, about 10 m above 92AD29-8 and slightly lower(?) than 28A-4.
Collected to the west of 92AD28A-4 and -22. (description from Harris E&R reports dated Jan. 25, 1995 (Shipment no. A-95-3a) and March 17, 1995 (Shipment no. A-95-3).] |
| Location: |
Alaska Quadrangle: Howard Pass B-5 Township&Range: T11S R29W Section: north part of sec. 13
Lat.: 68o29'45 " Long.: 158o35'10 " |
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Reference
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| Title: |
Report on Referred Fossils
,
1994
(05/03)
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| Report by: |
Robert B. Blodgett
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| Referred by: |
Julie A. Dumoulin
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| | Age: | Eifelian (early Eifelian) |
| Formation: | Unknown (Unknown (unnamed Devonian limestone)) |
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| Comment: | This sample was so extensively replaced by silica, that it could not be digested in acid for the recovery of silicified fauna. The most abundant species in all three collections of silicified brachiopods is Spinatrypa (Isospinatrypa) sp., which is conspecific with an undescribed species from the upper part of the Cheeneetnuk Limestone of west-central Alaska. The age of that part of the Cheeneetnuk is early Eifelian (early Early Middle Devonian). ... I would suggest an early Eifelian age for your collections, based on the mutual presence of Spinatrypa (Isospinatrypa) sp., with those of equivalent age faunas from the upper part of the Cheeneetnuk Limestone. As you are aware, Bill Brosge made extensive collections of your stratigraphic interva back in 1950 (localities 50ABe51, 52, and 53). In his collections I was able to also recognize a number of species in common with the Cheeneetnuk faunas of west-central and southwestern Alaska (from rocks of the so-called "Nixon Fork terrane"). This includes the rhynchonellid brachiopod Droharhynchia rzhonsnitskayae Baxter & Blodgett, 1994 (a nomen nudum, until legally published this Nov., 1994). This species also turns up in one of the Brosge samples, 50ABe53 (=UGS loc. 3370-SD). It is indeed intriguing to see suggestions of further alliance between Eifelian age faunas of northwestern and southwestern Alaska! |
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| Title: |
Geologic and Fossil Locality Maps of the West-Central Part of the Howard Pass Quadrangle and Part of the Adjacent Misheguk Mountain Quadrangle, Western Brooks Range, Alaska (part 2 of single issue))
,
2004
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| Report by: |
Jim Dover
,
Irv L. Tailleur
,
Julie A. Dumoulin
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| | Age: | Eifelian (Early Middle Devonian (early Eifelian)) |
| Formation: | Unnamed (Limestone (Devonian)) |
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| Comment: | Age: early Middle Devonian (early Eifelian) Shown as locality 74 on Sheet 2; map unit: Dl Baxter and Blodgett (1994) reported the brachiopod Droharhynchia rzhonsitskayae n. sp. from this general locality (50ABe53; USGS coll. 3370-SD); brachiopods of this genus may also occur in the Kolyma region of northeastern Siberia Table 1 contains conodont data from this locality. [all data given here from Dover et al., 2004, p. 65 (Table 3)] REFERENCE
Baxter, M.E., and Blodgett, R.B., 1994, A new species of Droharhynchia (Brachiopoda) from the lower Middle Devonian (Eifelian) of west-central Alaska: Journal of Paleontology, v. 68, p. 1235-1240. |
| Occurrence(s) |
| No. |
Group |
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Name |
Qty |
Notes |
| 1 |
Brachiopods |
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Spinatrypa (Isospinatrypa) sp. |
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Spinatyrpa (Isospinatrypa) sp. is conspecific with an undescribed species from the upper part of the Cheeneentnuk Limestone of west-central Alaska. Brachiopod identified by R.B. Blodgett, USGS. |
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| Title: |
Report on Referred Fossils
,
1995
(03/17)
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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
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| Referred by: |
Julie A. Dumoulin
,
J. H. Dover
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| | Age: | Eifelian (Eifelian, but not very earliest Eifelian) |
| Formation: | Unnamed (unnamed Devonian limestone) |
| CAI: | Min: 3 |
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| Comment: | Age: Po. costatus costatus Zone through Po. ensensis Zone (upper of range limited by age of overlying samples); = Eifelian, but not very earliest Eifelian.
Biofacies: Indeterminate (too few conodonts); probably from or within polygnathid biofacies; normal-marine, shelfal depositional environment.
CAI 3. Heavy mineral concentrate: chiefly dolomite rhomabs and minor iron oxides. The +20 mesh acid insoluble residue was give to R. Blodgett for brachiopod analysis. |
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| Title: |
Report on Referred Fossils
,
1995
(01/25)
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All conodont analyses and samples and residue weights are given in the attached tables. The age range of all samples is graphically shown on the accompanying diagram. Please give a copy of this report to Jim Dover and anyone else on the Howard Pass project that needs these data. I will do all the Carboniferous samples while in Florida. |
| Report by: |
Anita G. Harris
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| Referred by: |
Julie A. Dumoulin
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| | Age: | Eifelian (Eifelian, but not very earliest Eifelian) |
| Formation: | Unnamed (unnamed Devonian limestone) |
| CAI: | Min: 3 |
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| Comment: | Age: Po. costatus costatus Zone through Po. ensensis Zone (upper part of range limited by age of overlying samples); = Eifelian, but not very earliest Eifelian.
Biofacies: Indeterminate (too few conodonts); probably from or within polygnathid biofacies; normal-marine, shelfal depositional environement.
CAI=3 Heavy-mineral concentrate: chiefly dolomite rhombs and minor iron oxides. The +20 mesh acid residue was given to R. Blodgett for brachiopod analysis.
Wgt. (kg) 5.4; >20 mesh insol. res., (grams) 3000; 20-200 mesh insol. res., (grams) 39 |
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