NS3678 : Course of a geological dyke

taken 4 years ago, near to Cardross, Argyll And Bute, Great Britain

Course of a geological dyke
Course of a geological dyke
To the right of a line receding directly from the photographer's location, the ground falls away. This line corresponds to what is very probably the geological dyke that is marked on the 1:50000 BGS map (S030W Greenock (S)); there, it is marked "D", the key indicating that the dyke is composed of "olivine-dolerite, olivine-basalt and hawaiite". It runs E-W, and, on satellite imagery, traces of its continuation can be discerned in the nearer part of the field that can be seen beyond the line of trees straight ahead.

The dyke is marked on the annotated satellite map that is linked from the end-note. See LinkExternal link for a zoomed-in view centred on this part of the dyke.

The Firth of Clyde is in the background.

See NS3678 : Pit on geological dyke for a pit about 40 metres ahead. See NS3678 : Course of a geological dyke for a view in the opposite direction.
Carman Muir: outcrops and old quarry pits :: NS3778
See LinkExternal link (in a Geograph article) for further information, and LinkExternal link for an annotated satellite view on which various features of geological interest (as well as traces of associated industries and other antiquities) are marked, as described below.

The topography of the parts of Carman Muir to the south of Cardross Road is determined to a large extent by cornstone deposits, which outcrop in places. Cornstone is an impure granular limestone, a fossil soil. Old quarry pits (probably worked before the nineteenth century) and possible test pits can be seen along the lines of these deposits; they are indicated by light blue marker pins on the annotated satellite view, and the cornstone outcrops are marked by orange pins.

This area, lying to the south of Cardross Road, exemplifies what the British Geological Survey refers to as the Kinnesswood Formation (see LinkExternal link at the BGS website for more information); this formation contains cornstone deposits.

Beside and to the north of Cardross Road are outcrops of sandstone rather than cornstone. The sandstone is best seen along a line of outcrops and pits beside the road (these are indicated by reddish marker pins on the annotated satellite view). Another prominent example lies at the ENE end of that line: a large disused red sandstone quarry, the old Fairy Knowe Quarry (later known as Carman Quarry) LinkExternal link at NS36967900. This area beside and to the north of the road exemplifies the Stockiemuir Sandstone Formation (see LinkExternal link at the BGS website for further details).

Both north and south of the road, the strata in this area generally dip at an angle of from 10 to 20 from the horizontal, descending towards the SSE; the Stockiemuir Sandstone Formation that is exposed beside and to the north of the road underlies the cornstone-containing Kinnesswood Formation to the south of the road.

The annotated satellite view also includes markers for various antiquities in the area:

● Ancient cairns: LinkExternal link
● Hut circle: LinkExternal link
● Carman (house): LinkExternal link
● Carman (enclosure): LinkExternal link
● Carman (field system): LinkExternal link
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NS3678, 130 images   (more nearby )
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Date Taken
Wednesday, 20 May, 2015   (more nearby)
Friday, 22 May, 2015
Geographical Context
Geological interest 
Primary Subject of Photo
Geological Feature 
Subject Location
OSGB36: geotagged! NS 3640 7864 [10m precision]
WGS84: 55:58.3676N 4:37.3889W
Camera Location
OSGB36: geotagged! NS 3645 7864
View Direction
WEST (about 270 degrees)
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Geological Dyke 

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