Littoral Karren Along the Western Shore of Newfoundland

Abstract

<p>The west coast of Newfoundland, from Port au Port Peninsula north to Pistolet Bay, displays many lower Cambrian to Middle Ordovician carbonate rock formations. These host a wide variety of modern littoral karren in the form of solution pits, pans and grooves. lntrasite karren variation has been studied with respect to tidal range, biological species colonization and basic seawater properties of the tidal pools. An attempt is made to quantify intersite karren variation with respect to variations in lithology and the marine environment. This is the first study of littoral karren in a cold marine environment with seasonal sea ice fast to the coast. Field methods used stratified random sampling because the karren distribution is essentially zonal in nature. Shore-normal, parallel transects were taken across the platforms, with metre square quadrats used to obtain representative samples from each karren zone. Temperature, salinity, conductivity and pH were recorded in inter-, supratidal and backshore rock pools, with more detailed chemical analyses at one selected site. There is a general inrasite tend in karren development with karren diameter and microrelief increasing in size with increasing height above the mean low water mark (MLWM). This produces a corresponding inverse relationship between karren density and height above the MLWM Bioerosion is not a factor in explaining karren variation within the littoral zone, and there were no established relationships between SpC or pH and karren development, although intersite variations in geology and the marine environment may be obscuring the importance of chemical dissolution here. Bivariate and multivariate regressions are performed involving a number of geologic and marine environment variables, in an attempt to quantify intersite karren variations at western Newfoundland. Geologic factors, especially insoluble residue, are more important in determinrng if karren will develop beyond the scale of micropits at a given site, regardless of how exposed that shoreline is to the open marine environment. The marine environment, especially variations in the exposure index (EI), appears to be more important than geolory in explaining intersite karren variation between sites where measurable karren do occur</p>