Sample: |
Sample No. 92AD50C -- USGS No. 32447-PC
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Locality: |
Field No. 92AD50C
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Description: |
Howard Pass C-5. Lat. 68o 44'45" N., Long. 158o 55'35" W. Possibly graded-bedded, partly silicified limestone rich in crinoid columnals. Thin section is medium- to coarse-grained, poorly sorted, diverse skeletal grainstone. Bioclasts chiefly crinoid ossicles (20-40 percent), along with lesser bryozoans, foraminifers, siliceous sponge spicules, brachiopod fragments, and ostracodes; lithoclasts include glauconite, micrite, noncalcarous (locally spiculitic) mudstone and phosphate. Collected approx. 15 m below top of approx. 50-60-m-thick section of unit Mlri. Stratigraphic up seems to be to the south, based on sedimentary structures; section could be structurally thickened. If section is depositionally continuous, 92AD52A (loc. 3) should be near botton. This is the furthest northwest exposure of unit Mlri in the Howard Pass 1:250,000 quadrangle. (description from Dover et al., 2004, p. 29 (Table 1)); [Howard Pass C-5. 68°44'47", 158°55'35". Possibly graded-bedded, partly silicified limestone rich in crinoid columnals. Collected ~15 m below top of ~50-60 m-thick section of Ipnavik facies of Lisburne Group. Stratigraphic up seems to be to the south, based on sedimentary structures (but could be structually repeated). If section is not repeated, 92AD52A should be near top and 50C should be near bottom. Collected at 760+ m elevation, on top of small knob, ~2 miles due west of Jubilee Creek and ~3/4 mile east of hill 815 m; center sec. 13, T. 8 S., R. 30 W. This is the furthest northwest exposure of Ipnavik facies in the Howard Pass quadrangle. (description from Harris E&R report dated March 7, 1995, shipment A-95-3)] |
Location: |
Alaska Quadrangle: Howard Pass C-5 Township&Range: 8 S. 30 W. Section: 13 Lat.: 68o44'45 " Long.: 158o55'35 " |
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Reference
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Occurrence(s) |
No. |
Group |
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Name |
Qty |
Notes |
1 |
Conodonts |
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1 Pa frament Bactrognathus excavatus Branson and Mehl |
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all conodonts identified by A.G. Harris |
2 |
Conodonts |
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16 Pa elements Bispathodus stabilis (Branson and Mehl) ..... |
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3 |
Conodonts |
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..... or Bi. utahensis Sandberg and Gutschick |
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4 |
Conodonts |
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1 "Hindeodella" segaformis Bischoff s.f. bar fragment |
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5 |
Conodonts |
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Idioprioniodus conjunctus (Gunnell), 6 Pa, 3 M, 6 Sa, and 18 Sb-Sc elements |
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6 |
Conodonts |
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Kladognathus sp., 3 P, 8 M, 4 Sa, and 7 Sb-Sc elements |
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7 |
Conodonts |
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17 Pa elements Polygnathus communis cairna Hass |
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8 |
Conodonts |
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2 Pa fragments Polygnathus spp. indet. |
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9 |
Conodonts |
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1 Pa element fragment Pseudopolygnathus pinnatus (Voges) |
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10 |
Conodonts |
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2 Scaliognathus praeanchoralis Lane, Sandberg, and Ziegler fragments |
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11 |
Conodonts |
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6 Pb elements Scaliognathus sp. indet. |
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12 |
Conodonts |
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48 indet. bar, blade, and platform fragments |
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13 |
Conodonts |
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13 Pa elements Pseudopolygnathus primus Branson and Mehl |
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Redeposited late Kinderhookian conodonts |
14 |
Conodonts |
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3 incomplete Pa elements Siphonodella isosticha (Cooper) |
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Redeposited late Kinderhookian conodonts |
15 |
Conodonts |
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5 Pa element fragments Siphonodella sp. indet. |
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Redeposited late Kinderhookian conodonts |
16 |
Conodonts |
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8 Pa elements Gnathodus punctatus (Cooper) |
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Redeposited late Kinderhookian or early Osagean conodonts |
17 |
Conodonts |
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Unassigned elements: 5 Pb (3 morphotypes) and 9 M (4 morphotypes) |
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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: | Osagean (no older than middle Osagean) |
Formation: | Lisburne Group (Lisburne Group (Ipnavik facies)) |
CAI: | Min: 1.5 - Max: 2 |
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Comment: | Age: No older than Scaliognthus anchoralis-Doliognathus latus Zone (middle Osagean) with redeposited Kinderhookian and possibly early Osagean conodonts. This species association and mixture of biofacies and ages is characteristic of the Rim Butte unit (Ipnavik allochthon). Biofacies: Mixed biofacies and age; outer shelf or deeper water depositional setting, probably a turbidite. CAI = 1.5-2 10.1 kg of rock processed (1540 g of +20 mesh and 372 g 20-140 mesh insoluble residue). Heavy-mineral concentrate: chiefly phosphatized composite grains, phosphatic brachiopod fragments, unpicked conodont fragments and minor iron oxides. |
Occurrence(s) |
No. |
Group |
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Name |
Qty |
Notes |
1 |
Conodonts |
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1 Pa element fragment Bactrognathus excavatus Branson and Mehl |
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2 |
Conodonts |
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16 Pa elements Bispathodus stabilis (Branson and Mehl) ..... |
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3 |
Conodonts |
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... or Bispathodus utahensis Sandberg and Gutschick |
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4 |
Conodonts |
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1 "Hindeodella" segaformis Bischoff s.f. bar fragment |
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5 |
Conodonts |
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Idioprioniodus conjunctus (Gunnell) |
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6 Pa, 3 M, 6 Sa, and 18 Sb-Sc elements |
6 |
Conodonts |
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Kladognathus sp. |
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3 P, 8 M, 4 Sa, and 7 Sb-Sc elements |
7 |
Conodonts |
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17 Pa elements Polygnathus communis cairna Hass |
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8 |
Conodonts |
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2 Pa fragments Polygnathus spp. indet. |
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9 |
Conodonts |
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1 Pa element fragment Pseudopolygnathus pinnatus (Voges) |
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10 |
Conodonts |
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2 Scaliognathus praeanchoralis Lane, Sandberg, and Ziegler fragments |
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11 |
Conodonts |
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6 Pb elements Scaliognathus sp. indet. |
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12 |
Conodonts |
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48 indet. bar, blade, and platform fragments |
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13 |
Conodonts |
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REDEPOSITED LATE KINDERHOOKIAN CONODONTS: |
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14 |
Conodonts |
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13 Pa element Pseudopolygnathus primus Branson and Mehl |
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15 |
Conodonts |
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3 incomplete Pa elements Siphonodella isosticha (Cooper) |
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16 |
Conodonts |
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5 Pa element fragments Siphonodella sp. indet. |
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17 |
Conodonts |
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REDEPOSITED LATE KINDERHOOKIAN OR EARLY OSAGEAN CONODONTS |
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18 |
Conodonts |
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8 Pa elements Gnathodus punctatus (Cooper) |
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19 |
Conodonts |
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UNASSIGNED ELEMENTS: |
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5 Pb (3 morphotypes) and 9 M (4 morphotypes) |
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