Written by Andrew Shumway, Postdoctoral Researcher on the College of Washington
It’s not widespread for a rover to identify practically good spheres within the soil beneath its wheels. Over 20 years in the past, the Alternative rover famously found spherules made from hematite (nicknamed “blueberries”) close to its touchdown web site in Meridiani Planum. Extra just lately, the Perseverance rover has equally encountered spherules embedded in bedrock and loosely scattered all through the area informally known as “Witch Hazel Hill.” In a previous blog post, we described Perseverance’s investigations of a spherule-bearing outcrop on the “Hare Bay” abrasion patch, the place the staff later collected a core. With the “Bell Island” pattern added to the rover’s assortment, the science staff subsequent determined to take a better have a look at free spherules within the space, which seem to have eroded out of the close by bedrock.
On Sol 1555, whereas the US was celebrating the Fourth of July with hotdogs and fireworks, Perseverance was arduous at work learning spherule-rich regolith on the goal “Rowsell Hill” utilizing the proximity devices on its robotic arm. SHERLOC’s Autofocus and Context Imager and WATSON digicam each captured excessive decision footage of the goal (proven above), whereas PIXL measured the basic make-up of the spherules and surrounding grains.
Regardless of their superficial similarity to Alternative’s “blueberries”, the spherules at “Rowsell Hill” have a really completely different composition and certain origin. In Meridiani Planum, the spherules have been composed of the mineral hematite and have been interpreted to have shaped in groundwater-saturated sediments in Mars’ distant previous. By comparability, the spherules in “Rowsell Hill” have a basaltic composition and certain shaped throughout a meteoroid affect or volcanic eruption. When a meteoroid crashes into the floor of Mars, it may well soften rock and ship molten droplets spraying into the air. These droplets can then quickly cool, solidifying into spherules that rain down on the encompassing space. Alternatively, the spherules could have shaped from molten lava throughout a volcanic eruption.
With these new knowledge in hand, the Perseverance science staff continues to seek for solutions about the place these spherules got here from. In the event that they shaped throughout an historical affect, they can inform us concerning the composition of the meteoroid and the significance of affect cratering in early Mars’s historical past. In the event that they as an alternative shaped throughout a volcanic eruption, they may protect clues about previous volcanism within the area round Jezero crater. Both approach, these spherules are a remnant of an brisk and dynamic interval in Mars’ historical past!