The phrase "a thick layer of dust" is correct and usable in written English.
It can be used to describe a significant accumulation of dust on a surface, often implying neglect or lack of cleaning.
Example: "After weeks of being away, I returned to find a thick layer of dust covering the furniture in my living room."
Alternatives: "a heavy coating of dust" or "a dense layer of dust."
Time had blanketed the room with a thick layer of dust.
Thornton ran his hand along the omakase bar, disturbing a thick layer of dust.
Inside, a thick layer of dust coated what little furniture was in evidence: two tables pushed awkwardly against a wall.
Our biggest problem was a thick layer of dust on the window sills, but we washed and cleaned everything.
The shoes were covered by a thick layer of dust: the new era obviously had no use for them.
The gleaming airport terminals had a thick layer of dust on them, somewhat spoiling the futuristic effect.
According to the story, her family found her several days later, her eyes sealed shut and encrusted with a thick layer of dirt and dust.
It had been snowing but there was a thick layer of coal dust, as the protesters had been using coal sacks as sandbags.
But at the main Zaatari camp, about 25,000 people remain in a vast city of white tents turned yellow by lashing sand that quickly coats clothes, faces and young lungs with a thick layer of fine dust.
A thick layer of interstellar dust obscures much of the Galaxy from scrutiny by optical telescopes, and astronomers can determine its large-scale structure only with the aid of radio and infrared telescopes, which can detect the forms of radiation that penetrate the obscuring matter.
You are probably familiar with the scene: the sun is flooding through the office windows lifting your spirits, until it casts a rosy glow over the thick layer of dust and the leaning tower of yellowing papers and rubbish piled high on your desk.
