Articles | Volume 15, issue 7
Biogeosciences, 15, 2189–2203, 2018
Biogeosciences, 15, 2189–2203, 2018

Research article 13 Apr 2018

Research article | 13 Apr 2018

The extant shore platform stromatolite (SPS) facies association: a glimpse into the Archean?

Alan Smith1,6, Andrew Cooper1,2, Saumitra Misra1, Vishal Bharuth3, Lisa Guastella4,6, and Riaan Botes5 Alan Smith et al.
  • 1Discipline of Geology, School of Agriculture, Earth and Environmental Sciences, University of KwaZulu-Natal, Westville 3630, South Africa
  • 2School of Environmental Science, University of Ulster, Coleraine, Northern Ireland, UK
  • 3Microscopy and Microanalysis Unit, University of KwaZulu Natal, Westville 3630, South Africa
  • 4Bayworld Centre for Research and Education (BCRE), Cape Town, South Africa
  • 5Geo-Dynamic Systems, P.O. Box 1283, Westville 3630, South Africa
  • 6Coast Busters Inc Research Group, 29 Brown's Grove, Sherwood, Durban 4091, South Africa

Abstract. Shore platform stromatolites (SPS) were first noted at Cape Morgan on the south-east African seaboard. Since then they have been found growing discontinuously in rocky peritidal zones along the entire southern African seaboard. They have also been found on the southwest Australian coast, at Giant's Causeway in Northern Ireland, and more recently at Harris on the Scottish Hebridean Atlantic coast. In this paper SPS occurrence and SPS potential as analogues for Precambrian fossil stromatolites, as well as potential stromatolite occurrences in shore platform regions on Mars, are assessed. Sub-horizontal surfaces promote stromatolite development, while tufa develops on cliffs and steep rocky surfaces. Tufa and stromatolites are end members of a spectrum dictated by coastal topography. Extant SPS occur on well indurated shore platforms in high wave energy settings, often around or near headlands. They can be associated with boulder beaches, boulder ridges, storm swash terraces, coastal dunes, and peat bogs. In contrast to other extant stromatolites, SPS are produced primarily by mineral precipitation, although minor trapping and binding stromatolites do occur. From a geological perspective, SPS develop in mildly transgressive siliciclastic settings in various climatic and tidal regimes. We suggest that SPS could be preserved in the geological record as micritic lenses on palaeo-shore platform surfaces. SPS share many features with Precambrian stromatolites and are a valid modern analogue despite the widely different atmospheric and oceanic conditions of the Archean. We suggest that terraces associated with former oceanic or lacustrine flooding surfaces on Mars are potential targets in the search for palaeo-SPS on Mars.

Short summary
Growing shore-platform stromatolites are increasingly found on modern rocky coasts. Stromatolites are very similar to Archean and Proterozoic stromatolites. A study of modern stromatolites may shed light on the conditions that existed on the early Earth and other planets and possibly provide information on how life began.
Final-revised paper