Precambrian non-marine stromatolites in alluvial fan deposits, the Copper Harbor Conglomerate, upper Michigan

Laminated cryptalgal carbonates occur in the Precambrian Copper Harbor Conglomerate of northern Michigan, which was deposited in the Keweenawan Trough, an aborted proto-oceanic rift. This unit is composed of three major facies deposited by braided streams on a large alluvial-fan complex. Coarse clastics were deposited in braided channels, predominantly as longitudinal bars, whereas cross-bedded sandstones were deposited by migrating dunes or linguoid bars. Fine-grained overbank deposits accumulated in abandoned channels. Gypsum moulds and carbonate-filled cracks suggest an arid climate during deposition. Stromatolites interstratified with these clastic facies occur as laterally linked drapes over cobbles, as laterally linked contorted beds in mudstone, as oncolites, and as poorly developed mats in coarse sandstones. Stromatolites also are interbedded with oolitic beds and intraclastic conglomerates. Stromatolitic microstructure consists of alternating detrital and carbonate laminae, and open-space structures. Radial-fibrous calcite fans are superimposed on the laminae. The laminae are interpreted as algal in origin, whereas the origin of the radial fibrous calcite is problematic. The stromatolites are inferred to have grown in lakes which occupied abandoned channels on the fan surface. Standing water on a permeable alluvial fan in an arid climate requires a high water table maintained by high precipitation, or local elevation of the water table, possibly due to the close proximity of a lake. Occurrence of stromatolites in the upper part of the Copper Harbor Conglomerate near the base of the lacustrine Nonesuch Shale suggests that these depositional sites may have been near the Nonesuch Lake.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72022/1/j.1365-3091.1983.tb00713.x.pd

Vertebrate tracks in late pleistocene-early holocene (?) carbonate aeolianites, paphos, cyprus

In 2005, numerous vertebrate tracks were discovered in carbonate aeolianites in and around the town of Paphos, in the southwestern part of Cyprus. The main track-bearing exposure is located in a protected archaeological site near the Agia Solomoni Church inside the city of Paphos, where cross-sections through tracks are abundant in vertical exposures of the aeolianite along Apostolou Pavlou Avenue. Some exposures show as many as 10 tracks per m2 of vertical exposure. Several additional tracks were found in the extensive subterranean tomb complex, the Tombs of the Kings, just outside Paphos. The aeolian deposit was formed when westerly to south- westerly winds drove fine- to medium-grained calcareous sand onshore from the beach. This generated low coastal dunes, represented by 1-2-m-thick, cross-bedded sets made up of grainflow and wind-ripple strata, and sand sheets composed entirely of wind-ripple strata. The sediment does not yet have an absolute date, but is conside- red to be of Late Pleistocene to Early Holocene age, as are many other coastal aeolianites in the Mediterranean area. The Late Pleistocene endemic fauna in Cyprus was limited to the dwarf hippopotamus Phanourios minor Desmarest, 1822, the dwarf elephant Elephas cypriotes Bate, 1902, a small carnivore Genetta plesictoides Bate, 1903, and (possibly) humans. The exposed tracks are 5-15 cm in diameter, with a few tracks up to 23 cm in size. This range of size correlates well with the estimated foot size of dwarf hippopotami and dwarf elephants. This low-diversity, endemic island fauna provides a unique opportunity to correlate tracks with trackmakers. © 2015, Geological Society of Poland. All rights reserved

Paleo-Yardangs -- Wind-Scoured Desert Landforms at the Permo-Triassic Unconformity

In Canyonlands National Park, south-east Utah, at least 29 partly exhumed, aligned sandstone ridges trending generally N20-degrees-W occur at the upper unconformable surface of the Lower Permian (Leonardian) White Rim Sandstone. The ridges are at least 1.5 km long, 250 m wide and have up to 14 m of vertical relief (mean of 9 m). A thin lag of coarse sandstone that contains wind-ripple laminae and granule ripples directly overlies the ridges. Angular blocks of sandstone within the lag and sand-filled fissures immediately below the lag, within the ridges, attest to early cementation of the ridge-forming material. SE-dipping aeolian cross-strata within the White Rim Sandstone and within the lag closely parallel the ridge trend. The ridges are interpreted as wind-sculpted desert landforms (yardangs) that developed on the lithified upper surface of the White Rim Sandstone during an extended period of hyperaridity towards the end of the Permian