In the episode "The Man Trap" Captain Kirk, chief medical officer McCoy and crewman Darnell visit the surface of the fictional planet M-113. Soon they are hunted by a mysterious
shape-shifting creature that requires salt to survive and
is willing to obtain it by any means necessary. Crewman Darnell is the
first victim of the "Salt-Vampire" and also the first "red-shirt"
(wearing a blue shirt) to be killed in TOS. It is curious to wonder why the "Salt-Vampire" needs salt on such a planet.
Star Trek was among the first TV series to be filmed in color. M-113 is a desert planet, covered in yellow sand dunes and dark rocky outcrops, with an eerie reddish sky. M-113 reseambles surprisingly the planet Mars, even if at the time Star Trek was filmed nothing was known of its surface, visited by space probes only in 1976. Mars is today a dry planet with a thin carbon-dioxide atmosphere, but geological evidence suggests a dense atmosphere with a wet past.
Martian sky on September, 11, 2018. NASA/JPL
In 1849 the Italian chemist J. Usiglio performed a set of evaporation experiments with seawater along the French Riviera and established the order in which evaporite minerals precipitate from an aqueous environment. On earth these minerals are mostly gypsum and halite, associated with borates, potassium- and magnesium-salts. Such minerals if found in a stratigraphic column are compelling evidence for the former presence of water.
The Groeden sandstone was deposited in a landscape consisting of a succession of perennial and periodic rivers, alluvial fans, lakes and coastal plains in a semiarid climate (hot and dry with seasonal excessive rainfalls). Pedogenetic horizons with folded gypsum layers record strong evaporation and water level fluctuations. The upper cross-bedded sandstone records periods when meandering fluvial channels alternated with sand dunes of a desert environment.
Already from the orbit the Mars Global Surveyor identified terrains on Mars composed of a stratified material, covering a more rugged and cratered relief. To clarify the origin of these layers a field-investigation was necessary. In 2004 the Opportunity rover landed in the Eagle-Crater, located on the Meridiani-Planum - a flat, uniform plain with few impact craters. Opportunity spotted some outcrops in the small crater, however the exposed stratigraphic column was very short. The rover was therefore directed to the larger Endurance-Crater.
The outer rim of this crater provided an unique outcrop - soon named Burns-Cliff, after Roger Burns, who predicted the mineralogy of the Martian rocks (composed mainly of ultrabasic minerals, like olivine, and iron-sulfate minerals) based on the preliminary results obtained by the Viking missions.
Along the slope of the cliff geologists recognized a succession of rock types, or facies, named informally "Burns-Formation", the only extraterrestrial geologic formation at the time. The Burns-Formation consists almost entirely of sandstone with grains of basalt, oxides, silicates and evaporite minerals (calcium- and magnesium-sulfates, chlorides and phosphates). The Burns-Formation can be subdivided in three members:
- A lower unit of cross-bedded sandstone, probably sand dunes formed on a dry lakebed.
- A middle unit with laminated sandstone, interpreted as ancient sand sheet deposits of sporadic flood events. This units displays also various effects of groundwater infiltration, like dissolution of minerals and precipitation of new ones. Convoluted layers formed probably when minerals expanded due chemical reactions with the groundwater.
- The upper unit consists of laminated sandstone, layers of cross-laminated sandstone are interpretated as subaqueous ripples.
Already from the orbit the Mars Global Surveyor identified terrains on Mars composed of a stratified material, covering a more rugged and cratered relief. To clarify the origin of these layers a field-investigation was necessary. In 2004 the Opportunity rover landed in the Eagle-Crater, located on the Meridiani-Planum - a flat, uniform plain with few impact craters. Opportunity spotted some outcrops in the small crater, however the exposed stratigraphic column was very short. The rover was therefore directed to the larger Endurance-Crater.
The outer rim of this crater provided an unique outcrop - soon named Burns-Cliff, after Roger Burns, who predicted the mineralogy of the Martian rocks (composed mainly of ultrabasic minerals, like olivine, and iron-sulfate minerals) based on the preliminary results obtained by the Viking missions.
Along the slope of the cliff geologists recognized a succession of rock types, or facies, named informally "Burns-Formation", the only extraterrestrial geologic formation at the time. The Burns-Formation consists almost entirely of sandstone with grains of basalt, oxides, silicates and evaporite minerals (calcium- and magnesium-sulfates, chlorides and phosphates). The Burns-Formation can be subdivided in three members:
- A lower unit of cross-bedded sandstone, probably sand dunes formed on a dry lakebed.
- A middle unit with laminated sandstone, interpreted as ancient sand sheet deposits of sporadic flood events. This units displays also various effects of groundwater infiltration, like dissolution of minerals and precipitation of new ones. Convoluted layers formed probably when minerals expanded due chemical reactions with the groundwater.
- The upper unit consists of laminated sandstone, layers of cross-laminated sandstone are interpretated as subaqueous ripples.
The Burns-Formation at the Burns-Cliff, Endurance crater.
The Burns-Formation records the transition from a dry dune-field to a wet playa environment. Sporadic floods formed ripples and during dry periods minerals precipitated from the evaporating water. In later times Meridiani-Planum was covered for longer periods with water and maybe a shallow lake formed. This transition from dry to wet conditions occurred probably many times in the Martian past, as the dunes of the lower unit are already formed by reworked evaporites from older sediments. Liquid water implies a much dense atmosphere, even if not necessarily with oxygen.
If M-113 has a similar past as Mars, evaporite deposits should be common, including
sodium-chloride. Therefore, the Salt-Vampire should not need to kill to get salt. The still breathable atmosphere may remains of a former, more wet past. Mars lost most of its atmosphere over time, as gravity on such a small planet is too weak to hold on it.
If you enjoy this project, comment or may you even leave a tip.
The Burns-Formation records the transition from a dry dune-field to a wet playa environment. Sporadic floods formed ripples and during dry periods minerals precipitated from the evaporating water. In later times Meridiani-Planum was covered for longer periods with water and maybe a shallow lake formed. This transition from dry to wet conditions occurred probably many times in the Martian past, as the dunes of the lower unit are already formed by reworked evaporites from older sediments. Liquid water implies a much dense atmosphere, even if not necessarily with oxygen.
If M-113 has a similar past as Mars, evaporite deposits should be common, including
sodium-chloride. Therefore, the Salt-Vampire should not need to kill to get salt. The still breathable atmosphere may remains of a former, more wet past. Mars lost most of its atmosphere over time, as gravity on such a small planet is too weak to hold on it.
If you enjoy this project, comment or may you even leave a tip.
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