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Sample Detail
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Sample:
Sample No. No Data
Locality:
Field No. No Data
Description:
Bedded red chert collected from type locality of the McHugh Complex along the Seward Highway near Anchorage, Alaska. .... The sampled chert, found by Travis Hudson of the USGS, is located at the benchmark (BM 39) in sec. 15, T. 11 N., R. 3 W., in the Anchorage A-8 quadrangle and consists of a moderately well exposed block approximately 1 m by 2 m associated with altered mafic volcanic rocks. The volcanic rocks are massive and locally show crude pillow(?) structures. The contacts between the chert block and the surrounding volcanic rocks is covered. Smaller beds of chert were found in the vicinity of the sample site, but they did not yield radiolarians. Some red chert and volcanic rocks are intimately mixed; probably the mixing occurred while the chert was soft radiolarian ooze and it is therefore approximately the same age as the volcanic rock. (description from Karl and others, 1979, p. B88)
Location:
Alaska Quadrangle:
Anchorage
A-8 Township&Range: T11N R3W Section: Sec.15
Lat.: 61
o
02
'
37
"
Long.: 149
o
47
'
13
"
Reference
Title:
Early Cretaceous radiolarians from the McHugh Complex, south-central Alaska
, 1979
Report by:
Susan M. Karl
,
John D. Decker
,
David L. Jones
Age:
Valanginian
Formation:
McHugh Complex
Comment:
The chert from the McHugh Complex is here considered Valanginian on the basis of the age ranges of the following radilarian species: (see faunal list) [Note by R.B. Blodgett: the lat/long given was derived by digitization of locality (BM 39, sec. 15, T11N, R3W) on topographic map]
Occurrence(s)
No.
Group
Name
Qty
Notes
1
Radiolarian
Dictyomitra apiarium Rust
age range: Berriasian to Barremian (Foreman, 1975)
2
Radiolarian
Parvicingula citae Pessagno
age range: Valanginian (Pessagno, 1977)
3
Radiolarian
Podobursa triacantha(?) Fischli
age range: late Valanginian (Foreman, 1975; Pessagno, 1977)
4
Radiolarian
Sethocapsa cetia Foreman
age range: Berriasian to Valanginian (Foreman, 1975)
5
Radiolarian
Stichocapsa(?) rotunda Hinde
age range: Berriasian to Valanginian (Foreman, 1975)