Clare Basin Gallery

Click on hot spots on the index map to access photographic galleries of field stops along the shores of the Shannon Estuary and the Atlantic coast from Loop Head to Trusklieve.

Sandstone fills turbidite channels in the classic outcrops of the Ross Formation in Co. Clare. Lien et al 2003 determined flow directions from the localties whose photographic images are provided in the Galleries below.
Lien et al 2003 examined the classic outcrops of the Ross Formation, listed below, for Co. Clare at localities along the margins of Loop Head facing the Atlantic and the Shannon Estuary. Using the character of the stacking of channels and their sedimentary fill and interbedded sediments in these outcrops they were able determine the flow directions for the same stratigraphic interval. They interpreted these sedimentary bodies in terms of sinuous channel belts, shown in orange and yellow colors. Note that when Lien et al 2003 looked at a different stratigraphic interval, the sinuous channel belt model accommodates northwestward and northeastward flow directions for channels at Bridges of Ross and "Fisherman's Point". At yet another stratigraphic interval, the model accounts for northerly and northeasterly directions at Rinevilla and Cloonconeen. They took the bold step of linking the channels from these different localities.

In this figure Lien et al 2003 outline their conceptual model for the sinuous channel belt and the basin floor with no channels shown in the figure above this one.
Lien et al 2003 provided the conceptual model shown in this figure of a sinuous channel belt, passing downstream into a basin floor with no channels. They show only three channels within the belt, numbered 1 through 3 and coloured red, blue and green. They interpret each channel to have overbank spill lobes at channel bends -  showing some, but not all of these. They idenditify northward flows and preponderance of spillover lobes (packages) for Kilbaha Bay, and eastward flows are suggested for Gull Island.

Northwestward and northeastward flows are shown at Bridges of Ross, and unconfined tabular turbidites are shown at Ballybunion. They conclude that abrupt paleoflow changes may result from avulsion and/or changes in relative sea level associated with marine bands. In some of the sections they examined, prominent long term trends of paleoflow direction were shown in their Fig. 30 - these trends are indicated by curved arrows, and are interpreted to be the result of progressive downdip movement of sinuous channel belts, or progressive changes in the direction of supply to the basin floor (top right).

Figure from Lien et al 2003 with two stage channel filling model for the various channels exposed around Loop head in Co. Clare. Phase 1 shows lateral accretion, minimal aggradation, and spill of mudstones and thin-bedded turbidites over the cut bank. Phase 2 shows vertical aggradation, with individual beds scouring into the cut bank, forming steps. The fill consists of amalgamated sandstones. The more the channel aggrades, the more scouring (megaflutes) and spillover of thick-bedded amalgamated sandstones. The model is based on detailed observations, and boxes give figure references to the constituent parts of the model.

Galleries of Deepwater Sediments and the Clare Basin

Photographs and figures related to both deepwater systems and the sedimentary rocks of the Clare Basin outcroping on the shores of the Shannon Estuary to Loop Head and the Atlantic shore at Spanish Point accessed by clicking on images of these outcrops below. Their locations can be seen on the map at the base of the page. 





Namurian Geology of Clare basin with location map for field stops of Geology of Loop Head and flanks of Shannon Estuary.

Monday, October 28, 2013
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