NASA Mission Groundwork

Scientific Papers relating to PIXL and MISR

Adrian Galvin
3 min readApr 23, 2018

Global Age of Methanotrophy

C13(org) is a stable carbon isotope. An Isotope is an atomic variant of an element in which the number of neutrons is atypical. 13 refers to the mass number of the isotope, there are 13 nucleons (6 protons, 7 neutrons).

Neoarchean period is the latter part of the Archean eon, 4–2.5 billion years ago. During this time period, the Earth began to cool enough for continents to form. Lacustrine deposits are sedimentary formations which are formed at the bottom of lakes. Biogenic methane is severely C13 depleted as compared to photosynthetic biomass, which has lead to the conclusion that highly C13 depleted organic deposits from the Neoarchean represent a global age of methanotrophy.

Team hypothesizes that GAM is related to biological cycling of methane, promoted especially in oxidant deficient lakes (FE3+ and SO4) relative to the oceans.

Stromatolites | Stromatoliths are layered formations of microorganism biofilms which trap, bind and cement sedimentary rock grains. There are modern and fossilized examples of these cyanobacteria colonies.

A discussion involving questions of GAM, the probabilty and explanation of organic haze, archeal methanotrophs evolving into early methanogens, lacustrine and oceanic organic methane cycling dynamics and micro-XRF studies of described rock formations.

Strelly Pool Formation Stromatolite Carbon Trapping

Diagenesis is a process, during or following sedimentary lithification, in which sediment or sedimentary rock is converted to a different sedimentary rock.

There is debate regarding the biogenic origin of Strelly Pool Formation (SPF) Stromatolites, however the preponderance of opinion is that they are of biogenic origin.

PIXL Element Analysis of Rocks and Soils

PIXL is a micro-focus X-ray fluorescence instrument utilizing a 100nanometer diameter X-ray beam to detect the composition of rocks and soils. PIXL can scan to different levels of detail depending on scientific interest and mission necessity. It’s flexibility and capability can provide new insight into the potential past habitability of Mars.

Previous XRF instruments attained narrow focus by placing a pinhole in front of the X-ray emitter. This significantly reduces X-ray flux and increases integration time. PIXL utilizes a polycapillary optic to achieve a 100nanometer diameter spot at the focal point at 140x greater flux than a 100nanometer pinhole device.

Neoarchean Ooids

Ooids are inclusion grains which form in turbulent shallow water environments, generally less than or equal to 2mm. After formation, it is possible for a layer of ooids to be covered by sediment and converted into a rock called oolite. Crystal forms radially around a central grain, modern ooids are generally calcite or aragonite. Frequently formed within or associated with stromatolites.

Previously, it was thought that ooids were physicochemical in origin, but evidence indicates that modern ooids can be formed and disintigrated by microbial life forms. This study, performed on extremely well preserved calcite oolite shoals, indicates that ancient ooids were formed through similarly biologically mediated processes as modern ooids.

Meentheena Member ooids, in the Fortescue group, located within the Mount Bruce supergroup of Hamersley Bay in Western Australia, contain some of the same distinctive elements (radial fabrics, concentric laminae, silica replacement and kerogen clotting) as modern, biogenically mediated ooids. The conclusion is that ancient ooids were also biologically mediated, providing evidence of life back to 2.9Ga.

Earth’s Visible-Infrared Spectral Dimensionality

Imaging spectroscopy is the simultaneous collection of many spatially co-registered images across a variety of electromagnetic radiation bands. This paper focuses on quantifying the diversity of observed spectral content from Earth’s surface.

In general, urban environments appear to be the most spectrally diverse, and oceans appear to be the least spectrally diverse.

Visible to shortwave infrared spectrum (VSWIR) .38–2.5 nanometers contains the majority of surface-reflected solar radiation available for remote sensing. This study has implications for future mission instruments and intends to analyze across larger radiations of data across space and time.



Adrian Galvin

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