If your IQ were at least 70 you could figure out that a few thousand years of sunlight shinning on a bone sticking out of a cliff would cook it pretty thouroughly.
But never mind, its way beyond your cognition level.
You can bake a bone in sunlight all you want. Its major constituent will still be...... collagen.
What do you think happens to the collagen? If the sunlight “melted” it (which would take absurdly high temperatures), it would still be a bunch of amino acids. It is not.
If it is not made of collagen, it is not bone. Dry bone is made of collagen.
It is a fossil. The article you cited calls it a fossil.
And I repeat to you, because obviously you need to be reminded.....
Finding collagen in a fossil = groundbreaking discovery.
Finding collagen in a bone = yeah so?
Still no citation for your “100% bone” lie. That is because you made it up, just like your outlandish model of sunlight ‘fossilization’.