Tom's Q&A - #1 - What produces most of Earth's oxygen?

This the answer?

Refined calculations and new evidence support a revolutionary suggestion that global-scale geologic events produced the bulk of Earth's oxygen supply, a NASA scientist reported today.

Scientists have long believed that oxygen collected in Earth's early atmosphere as a by-product of plant life from a process called photosynthesis, in which plants take carbon dioxide and water to produce organic matter and oxygen. Dr. David DesMarais, of NASA's Ames Research Center, Mountain View, CA, first suggested in 1992 a relationship between oxygen and the collision of continents, the resultant colossal mountain ranges and increased erosion burying huge amounts of organic matter in ocean beds.

"Although photosynthesis did provide an oxygen source strong enough to sustain the amount of existing oxygen, the creation and assembly of large modern-sized continents was responsible for early dramatic increases in oxygen," DesMarais said.

DesMarais today reported new evidence supporting his findings at the Geological Society of America meeting in Denver.

DesMarais' research correlates oxygen "surges" in the atmosphere 2.2 to 2.0 billion years ago with changes in the amount of carbon stored in Earth's crust at that time. During that time, several of Earth's "micro" continents crashed together forming new, stable modern-sized continents. As the continental fragments collided, towering mountain ranges formed. Their steep slopes produced rapid erosion and sedimentation, key to DesMarais' theory.

Hmm, haven't heard of this before...
You evidently copied and pasted from google or something

This is quite interesting, but I am looking for something that produces the most of earth's oxygen at this point in time... The thing you posted above would appear to be when humans didnt even exist....
This very well may be correct, but as stated above, this is only a theory...
Also, this does not actually say that it is responsible for the production of most of earth's oxygen as it says it was responsible for 'early dramatic increases in oxygen'. Which is not really the answer I am looking for.
I am looking for what 'Produces' not what 'Produced'.

Good job though Donal.
Next time, Don't cheat