All posts tagged Stratigraphy

Deformation of Sedimentary Rocks in Valles Marineris, Mars

Post by Dr. Joannah Metz, Shell Oil Company

 A large canyon system (up to 8 km deep) called Valles Marineris is located near the equator on Mars.  The relative timing between the formation of the Valles Marineris canyon system and various light-toned stratified deposits observed within the different chasmata remains an outstanding question for the geologic history of Mars (Malin and Edgett 2000; Okubo et al. 2008) .  Some of these stratified deposits have been deformed and understanding the mechanism(s) responsible for this deformation, both within and between chasmata, could provide insight into the relative timing of events within the Valles Marineris system (Metz et al. 2010).

Image 1

Image 1: Example of detached slabs from Melas Chasma. Subscene of CTX image P05_002828_1711

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by Mary Bourke on September 16, 2013  •  Permalink
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Posted by Mary Bourke on September 16, 2013

https://planetarygeomorphology.wordpress.com/2013/09/16/deformation-of-sedimentary-rocks-in-valles-marineris-mars/

Morphology+Mineralogy : what high-resolution morphology combined with infrared color and spectra can tell us about Mars environments

Posted by DR Bethany Ehlmann, Brown University.

The past decade of high resolution orbital imaging of Mars has revealed gullies, dune forms, fresh impact craters, polar layered deposits, and sedimentary stratigraphic sections through the use of the Mars Orbiter Camera (MOC; 1.5 m/pixel), the High Resolution Stereo Camera (HRSC; 2.3 m/pixel), the Context Imager (CTX, 5m/pixel), and the High-Resolution Imaging Science Experiment (HiRISE; 25cm/pixel). These have permitted detailed studies of aeolian, glacial/periglacial, and past fluvial processes that have shaped the development of Mars’ landscapes. Equally, the past five years of Mars exploration with orbital visible/near-infrared spectroscopy have led to the discovery of numerous classes of alteration minerals including clays, sulfates, and carbonates that provide information on the duration and chemical conditions of aqueous alteration, using the Observatoire pour la Minéralogie l’Eau les Glaces et l’Activité (OMEGA; 300m/pixel) and the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM; 18m/pixel).

Image 1: A mineral map derived from CRISM infrared spectra merged with a CTX image (a) shows that most of the thick sedimentary units filling the 40km crater are Fe/Mg smectite-bearing (magenta) but that these are overlain by a distinct, bright-toned kaolinite bearing material (green). Both have been exposed from beneath a capping unit (purple) by fluvial erosion of the deposits.

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by Mary Bourke on September 13, 2013  •  Permalink
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Posted by Mary Bourke on September 13, 2013

https://planetarygeomorphology.wordpress.com/2013/09/13/morphologymineralogy-what-high-resolution-morphology-combined-with-infrared-color-and-spectra-can-tell-us-about-mars-environments/

Stratigraphy of the Martian North Polar Ice Cap

Post by Kathryn Fishbaugh.

At the north pole of Mars lies Planum Boreum, a dome of layered, icy materials similar in some ways to the large ice caps in Greenland and Antarctica and comparable in size to the former. The dome itself consists of the polar layered deposits, consisting of over 90% ice with a little bit of dust, and the basal unit, consisting of ice, dust, and sand.

Mars Polar Deposits

An enhanced color image from the Mars Reconnaissance Orbiter (MRO) High Resolution Imaging Science Experiment (HiRISE) shows a portion of the martian north polar layered deposits, the basal unit, and the Olympia Undae dune field. The image is 1.2 km (0.75 mi) across. This image is best understood if you imagine yourself flying over a cliff in a plane. Note that the colors in an enhanced color image do not re-create what it would look like to the naked, human eye, but rather bring out the compositional differences between the materials.

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by Mary Bourke on September 11, 2013  •  Permalink
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Posted by Mary Bourke on September 11, 2013

https://planetarygeomorphology.wordpress.com/2013/09/11/stratigraphy-of-the-martian-north-polar-ice-cap/

Deltaic sediments on Mars

Post by Dr. Bethany Ehlmann

The Nili Fossae region of Mars has a diversity of minerals that include mafics and phyllosilicates. The mineral assemblage suggests widespread liquid water activity and a variety of alteration processes from surface weathering to hydrothermal processes (Mangold et al., 2007).

Nili Fossae, Mars

Image 1: CRISM infrared spectrometer data (wavelengths: 2.38 um (red), 1.80 um (green), 1.15 um (blue) acquired at 35 m/pixel have been used to colorize a Context Imager grayscale image, taken at 5 m/pixel resolution.

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by Mary Bourke on September 10, 2013  •  Permalink
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Posted by Mary Bourke on September 10, 2013

https://planetarygeomorphology.wordpress.com/2013/09/10/deltaic-sediments-on-mars/

Layered Deposits, Candor Chasma, Mars

Post by Dr Mariam Sowe

Candor Chasma is situated in the central Valles Marineris (Image 1). It is characterised by Interior Layered Deposits (ILDs) that are exposed on its valley floor. ILDs are closely connected to sulphate minerals and iron oxide [Christensen et al., 2001; Gendrin et al., 2005; Mangold et al., 2007]. Using high resolution images and elevation data from the Mars Express HRSC experiment [Jaumann et al., 2007] their layer geometry can be measured.

Candor Chasma, Mars

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by Mary Bourke on September 10, 2013  •  Permalink
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Posted by Mary Bourke on September 10, 2013

https://planetarygeomorphology.wordpress.com/2013/09/10/layered-deposits-candor-chasma-mars/

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