Page 165 - Carbonate Facies in Geologic History

152 The Lower Carboniferous Waulsortian Facies

51.° 5,,0

Longford

Dublin
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I //3 53°

• Limerick " ';

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Waterford

52°
Cork ' 10 20 30 1.0 SO miles
• ................... _ 0 II "0 I 60 eo km
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: : : : : ... : . : : : : : : : . : :
bank complex
. . .. . .. ::::::::' I'·::::;:! Offshore clastics D Waulsortian
;. : ... :; ;: : .: : : : : ::::. ~ Lagoon faCies with ::: Mud -bell faCies
scattered Waulsortian
10° 9° SO banks 7° SO
Fig.V-5. Paleogeography and lithofacies of the Waulsortian in southern Ireland. From Lees
(1961, Fig. 1). The Waulsortian mudbank facies is shown at its maximum extent occupying a
wide belt between the basinal mud belt (Culm) and the lagoonal facies. The latter also
contains numerous scattered banks which are not indicated. The land masses surrounded by
dotted lines are as follows: 1. Galway-Mayo, 2. Longforddown, and 3. Leinster
generally a subtidal environment. They are the lower part of a famous quarry
rock, the Marbre N oir.
A similar shelf margin Waulsortian facies is present in the western Midlands
of the British Isles (Lancashire and northwest Yorkshire). It also occurs in central
Ireland, surrounding positive elements in the Hercynian troughs and forming
large mounds rising more than 100 m within shale basins. Parkinson (1957) offers
a good review of these British "tufa mounds" and the map of Fig. V -3 is derived
from this work and from that of Hudson and Cotton (1945). The Irish outcrops
display relationships very similar to those of Britain (Fig. V-4, V-5). The best
modern petrographic studies of the former are by Lees (1961, 1964), Schwarz-
sacher (1961), and Philcox (1963,1967).