'thick darkness' is correct and usable in written English.
It is often used to create an atmosphere of gloom or foreboding. For example, "The thick darkness of the night was punctuated only by the occasional sound of an owl."
"Out of the thick darkness comes sudden light," he wrote.
Seated in a thick darkness, the audience will be surrounded by morphing and transforming sounds unlike anything typically heard in a concert hall.
During these months Moses used the plagues of the frogs, gnats, mosquitoes, cattle murrain, boils, hail, locusts, and thick darkness to increase the pressure on Ramses.
AS the first rays of the sun pierce the thick darkness of the Namibian desert, sinuous ridges of quartz sand ignite in a firestorm of seared orange.
How can one trust the memories of a medieval man who claims "the Kashmiri are all idolaters, they change the weather by enchantment, and bring down thick darkness"?
In Exodus, the skies of Pharaoh's Egypt were obscured by a plague of locusts, followed by a "thick darkness" lasting three days.
Like a feminine Thomas Ligotti with a very high sex drive, Furnace is a nightmarish wander through lust, violence and treacle-thick darkness.
From the chilly porch, I looked out into the thick, country darkness.
However thick the darkness, we drag ourselves into arguments, up to lecterns, because we have not let go of each other yet.
The kind of thick, enfolding darkness which in Pond's photographs both swallows and brings forth the most terrifying thing of all -- the unknown.
The brighter the candle, the thicker the darkness that follows it being extinguished seems.
