Computer Code: |
HERS |
Preferred Map Code: |
notEntered |
Status Code: |
Full |
Age range: |
Eocene Epoch (GE)
— Eocene Epoch (GE) |
Lithological Description: |
The Hermod Sandstone Member consists of clean, very fine to medium grained sandstone displaying distinctive 'blocky' log profiles. Thin intercalations of dark grey fissile mudstone are also present. |
Definition of Lower Boundary: |
The base of the Hermod Sandstone Member is taken at a downward change to mudstone, associated with an increase in gamma-ray values and a decrease in sonic velocity. Where the underlying Teal Sandstone Member (Sele unit 1) is thin (e.g. 10/1-1A ), the Hermod Sandstone Member rests on sandy mudstones that probably represent unit S2b (refer to Sele Formation); where the Teal Sandstone Member is thicker (e.g. 10/1-3), only a thin, high-gamma mudstone separates it from the underlying Teal Sandstone Member, possibly reflecting condensation over a mounded Teal Sandstone topography. |
Definition of Upper Boundary: |
The top of the Hermod Sandstone Member is taken at a downward change from mudstone to sandstone, associated with a decrease in gamma-ray values and an increase in velocity. |
Thickness: |
It is generally less than 100 m thick in the UK sector. |
Geographical Limits: |
The Hermod Sandstone Member is restricted to the North Viking Graben. |
Parent Unit: |
Sele Formation (SELE)
|
Previous Name(s): |
none recorded or not applicable
|
Alternative Name(s): |
none recorded or not applicable
|
Stratotypes: |
Type Section |
Norwegian Sector North Sea well N25/2-6 (Isaksen and Tonstad, 1989, fig. 56): 2221-2361 m (7287-7746 ft) below KB. This section may include representatives of the Teal Sandstone Member. |
Reference Section |
North Sea well 10/01- 1A: 2126-2212 m (6975-7257 ft) (Knox and Holloway, 1992). |
Reference Section |
North Sea well 10/01- 3: 2073-2178 m (6801-7146 ft) (Knox and Holloway, 1992). |
Reference(s): |
Knox, R W O'B and Holloway, S. 1992. 1. Paleogene of the Central and Northern North Sea. In: Knox, R W O'B and Cordey, W G (eds.) Lithostratigraphic nomenclature of the UK North Sea. British Geological Survey, Nottingham. |
Isaksen, D and Tonstad, K. 1989. A revised Cretaceous and Tertiary lithostratigraphic nomenclature for the Norwegian North Sea. NPD-Bulletin No.5 |
Mudge, D C and Copestake, P. 1992. Lower Palaeogene stratigraphy of the northern North Sea.Marine and Petroleum Geology,9,287-301. |
1:50K maps on which the lithostratigraphical unit is found, and map code used: |
none recorded or not applicable |