Geology of the Andover area: Concealed strata - Permian: Difference between revisions
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|+ '''Stratal thickness table'''. | |+ '''Stratal thickness table'''.</br>Key hydrocarbons boreholes and deeper wells in the Andover district and adjacent areas. | ||
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| '''Strata''' | | '''Strata''' |
Revision as of 10:24, 7 July 2014
This page is part of a category of pages providing a summary of the geology of the Andover district (British Geological Survey Sheet 283), which extends over approximately 600 km2 of north-west Hampshire and a small part of eastern Wiltshire. Links to other pages in this category can be found at the foot of the page. Authors: J Thompson, K A Lee, P M Hopson, A R Farrant, A J Newell, R J Marks, L B Bateson, M A Woods, I P Wilkinson and N J Smith. |
Permian strata are absent from wells but have been interpreted from seismic sections to be present in the west. The strata, as described in the neighbouring Devizes district explanation (Booth et al., 2011)[1], comprise interbedded, red, micaceous mudstone and siltstone with rare thin sandstone interbeds. The strata are displayed as an undivided Permo-Triassic unit on the cross-sections on the Andover 50k map.
Strata | Kingsclere | Egbury 1 | Upper Enham 1 | Ham 1 | Hurstbourne Tarrant | Carnarvon Arms |
Borehole number | SU45NE 1 | SU45SW 46 | SU35SE 23 | SU36SW 1 | SU35SE 27 | SU45NE 3 |
Grid reference | 49840 58200 | 44484 52364 | 36598 50430 | 33100 62470 | 36032 53500 | 45720 59450 |
Palaeogene | Absent | Absent | Absent | Absent | Absent | 124.6 |
White Chalk
Subgroup |
Absent | 170.6 | Absent | Absent | 217.6 | 12.5+ |
Grey Chalk
Subgroup |
Absent | 68.4 | Absent | 18.3 | ||
Upper Greensand
Formation |
33.8 | 70.0 | 57.7 | 42.7 | 62.8 | |
Gault Formation | 86.6 | 41.0 | 58.7 | 84.1 | 55.5 | |
Lower Greensand
Group |
13.7 | 10.5 | 11.3 | 4.8 | 10.4 | |
Wealden ‘Group’ | 178.9 | 118.5 | 127.1 | 11.0+ | 125.9 | |
Purbeck Group | 164.3 | 43.5 | 53.8 | 36.3 | ||
Portland Group | 43.6 | 46.0 | 53.4 | 50.0 | ||
Kimmeridge Clay
Formation |
284.4 | 187.5 | 203.2 | 218.2 | ||
Corallian Group | 53.6 | 58.0 | 57.5 | 125.0 | ||
Oxford Clay
Formation |
95.1 | 117.3 | 132.7 | 25.0 | ||
Kellaways Formation | 9.1 | 10.5 | 14.0 | 14.0 | ||
Great Oolite Group | 85.0 | 93.9 | 108.1 | 61.0 | ||
Inferior Oolite
Group |
109.4 | 48.3 | 75.9 | 118.3 | ||
Lias Group† | 360.9+ | 377.7 | 495.5 | 38.4+ | ||
Penarth Group | 9.3 | 28.5+ | ||||
Permo-Triassic | Absent | |||||
Ordovician to Carboniferous | 29.0+ |
Notes: †The Lias Group undivided encompasses the old divisions of Lower, Middle and Upper Lias. Modern terminology that can be applied to the strata encountered in these boreholes is discussed on the Jurassic page.
References
- ↑ Booth, K A. 2001. Geology of the Wherwell–Bullington district, Hampshire. British Geological Survey Technical Report, WA/01/08.