Feasibility of an 'Oxygen Radiation Zone': a non-pressurized natural formation on Mars that provides suitable atmosphere

CONTEXT and INTRODUCTION

Humans establish colonies on Mars with slightly more advanced technology than we have today. The Martian colonists lose all contact with Earth. Over centuries, the Martian colonists develop a distinct culture (w/ practices, religion, language, etc). My story takes place in this culture. A fundamental defining element of this culture is technophobia / technological deterioration (for various irrelevant reasons).

I have two issues pertaining to the atmosphere of Mars that prevent human habitation. Firstly, the chemical composition of the Martian atmosphere is unsuitable: low O$_2$ and high CO$_2$. Secondly, the atmospheric pressure of Mars averages a mere 600 pascals which is unsuitable for human habitation. Somehow, my Martians need to be able to inhabit Mars and survive (but not thrive).

However, as aforementioned, the Martian populace are technophobic. Their technology is rather primitive, technological development is almost non-existent and technology from the very first colonies is irreproducible and/or lost. As such, terraforming is out of the question. As are more advanced technologies, such as spacesuits and pressurized habitats.

THE "OXYGEN RADIATION ZONE"

Therefore, I am trying to devise a theoretical natural formation that provides the Martians with a localised habitable area.

Currently, this natural formation is an unpressurized "˜Oxygen Radiation Zone'. Oxygen is released from underground in a volume significant enough to provide a local area with suitable atmospheric pressure and composition for survival (but not "˜thrive-al'). I have included a diagram to better describe this "˜Oxygen Radiation Zone'. Please consider the diagram from a birds-eye-view.

Oxygen Radiation Zone Diagram

1. "˜Oxygen leak': where oxygen from underground is released in significant volume.

2. "˜Livable area': the area inside the black circle where atmospheric pressure and composition are suitable for human survival. Cities are built in a ring-like fashion, radiating from the "˜oxygen leak'.

3. The extent of the "˜livable area'.

4. "˜Transition area': where atmospheric composition and pressure are gradually returning to the Martian normal. This area is unlivable.

5. The extent of the "˜transition area': where atmospheric composition and pressure become indistinguishable from the Martian normal.

6. Martian normal.

NOTE: In the diagram, the areas are well-defined, but I imagine the whole thing to be a pressure gradient, from the high-pressure "˜oxygen leak' (1) to the low-pressure Martian normal (6).

COMPLICATION: Winds

My understanding of pressure systems is quite basic. From the research that I have done, air moves from an area of high-pressure to an area of low-pressure resulting in the generation of wind. The intensity of these winds is determined by the pressure gradient. Therefore the pressure gradient from (1) to (6) would have to be gradual to avoid unwanted strong winds. Is this correct? If so, would this gradual pressure gradient be extremely large in area?

COMPLICATION: Oxygen escape

I know that oxygen molecules would escape from this "˜Oxygen Radiation Zone', because of low gravity on Mars. However, the underground oxygen source that I have theorized is renewable and therefore I believe that this complication is mitigated, as long as influx of oxygen molecules matches efflux of oxygen molecules.

COMPLICATION: Dust storms and dust devils

Mars is asymmetrically heated in different seasons, which produces a mean overturning circulation called a Hadley cell. In short, this Hadley cell is responsible for the production of global-scale dust storms (among other things). Dust devils are localized convection cells that can reach 1 to 2 km at the bases and may be as tall as 8 to 10 km. How would these dust storms and devils interact with my "˜Oxygen Radiation Zone'? Would they be diverted around it?

CONCLUSION and QUESTIONS

I understand that this "˜Oxygen Radiation Zone' is not scientifically accurate to the minute detail.

Is my design somewhat scientifically feasible? Are there any major complications that I may need to consider?

This is a whopper of a question. Thank you for taking the time to read it and provide me with feedback.