Curiosity Views Spectacular Layered Rock Formations

[bystander]

Mars Rover Views Spectacular Layered Rock Formations
NASA | JPL-Caltech | MSL Curiosity | 2016 Sep 09

[c][attachment=0]curiosity-goes-up-a-mountain-full.jpg[/attachment]Curiosity Makes Its Way Up A Martian Mountain
Credit: NASA/JPL-Caltech/MSSS[/c][hr][/hr]

The layered geologic past of Mars is revealed in stunning detail in new color images returned by NASA's Curiosity Mars rover, which is currently exploring the "Murray Buttes" region of lower Mount Sharp. The new images arguably rival photos taken in U.S. National Parks.

Curiosity took the images with its Mast Camera (Mastcam) on Sept. 8. The rover team plans to assemble several large, color mosaics from the multitude of images taken at this location in the near future. ...

The Martian buttes and mesas rising above the surface are eroded remnants of ancient sandstone that originated when winds deposited sand after lower Mount Sharp had formed. ...

The new images represent Curiosity's last stop in the Murray Buttes, where the rover has been driving for just over one month. As of this week, Curiosity has exited these buttes toward the south, driving up to the base of the final butte on its way out. In this location, the rover began its latest drilling campaign (on Sept. 9). After this drilling is completed, Curiosity will continue farther south and higher up Mount Sharp, leaving behind these spectacular formations. ...

[neufer]

[b][color=#0000FF][size=200]Pleistocene age varves at[/size] [size=125]Scarborough Bluffs, Toronto, Ontario, Canada.[/size] The thickest varves are more than half an inch thick.[/color][/b]

---

<<A varve is an annual layer of sediment or sedimentary rock. The word 'varve' derives from the Swedish word varv whose meanings and connotations include 'revolution', 'in layers', and 'circle'. The term first appeared as Hvarfig lera (varved clay) on the first map produced by the Geological Survey of Sweden in 1862. Initially, "varve" referred the separate components of annual layers in glacial lake sediments, but at the 1910 Geological Congress, the Swedish geologist Gerard De Geer (1858–1943) proposed a new formal definition, where varve means the whole of any annual sedimentary layer. More recently introduced terms such as 'annually laminated' are synonymous with varve.

Of the many rhythmites in the geological record, varves are one of the most important and illuminating in studies of past climate change. Varves are amongst the smallest-scale events recognised in stratigraphy.

An annual layer can be highly visible because the particles washed into the layer in the spring when there is greater flow strength are much coarser than those deposited later in the year. This forms a pair of layers—one coarse and one fine—for each annual cycle. Varves form only in fresh or brackish water, because the high levels of salt in normal sea water coagulate the clay into coarse grains. Since the saline waters leave coarse particles all year, it is nearly impossible to distinguish the individual layers in salt waters. Indeed, clay flocculation occurs at high ionic strength due to the collapse of the clay electrical double layer (EDL), which decreases the electrostatic repulsion between negatively charged clay particles.>>