Isolated areas of deposition in the basin occurred during the Late Permian through the Triassic as well as the Latest Jurassic.
At its base it consists of green shale and sandstone and coarsens upwards to arkosic conglomerates.
The Findikli Formation was deposited during the upper Ordovician, Silurian, and lowermost Devonian in the Zonguldak basin.
[2] The Yilanli Formation is Visean in age and is the beginning of the coal-related sequences in the Zonguldak basin.
[3][4] Facies analysis in the Alacaagzi Formation is suggestive of coastal environments including lacustrine, fluviatial, and fan deposits.
[6] During the late Cretaceous, the Zonguldak basin was roughly 25° N,[6] and was experiencing subsidence due to the formation of a back arc, the Black Sea.
[7] The unconformity lasts at least 6.5 Ma and the Zonguldak basin experiences continuous deposition from the Turonian – Campanian.
[7] During the middle Paleozoic, the Zonguldak basin was part of the south-facing passive margin of the Laurasian plate.
Similarly, the base of the Kozlu Formation reaches maximum temperatures of 85, 85, and 100 °C in the Armutcuk, the Zonguldak, and the Amasra regions, respectively.
[9] The Zonguldak basin was tectonically active during the late Paleozoic and this strongly influenced its structural and burial history due to the Hercynian orogeny.
[3][4] This uplift of the basin, near the end of the Westphalian, halted deposition and created the angular unconformity at the top of the Karadon Formation.
[2][4][5] Heat flow remained constant in the Zonguldak basin during the Hercynian Orogeny,[5] while the uplift decreased the temperatures the sediments experienced.
For example, at the end of the Permian the top of the Alacaagzi was roughly 70 °C and 1.6 km below the sediment surface in the Zonguldak area.
The start of this subduction is responsible for the unconformity between the Kilimi and Cemaller formations and marks the beginning of the Alpide orogeny in the region.
[6] The andesitic volcaniclastic sediments of the Yemislicay support the subduction of oceanic crust in the region during this time.
The Aplide orogeny stopped deposition and uplifted the Zonguldak basin during the Eocene epoch beginning at 42 Ma.
[9] The Alpide tectonic provinces in Anatolia, from north to south, are the Pontides, Anatolides, Tarides, and Border Folds.
[11] Thermogenic production of methane in coals begins at temperatures around 80 °C and peaks around 0.7–1.6% of vitrinite reflectance.
[11] Typically, biogenic production takes place early in the maturation of a coal bed, since the temperatures observed during the coalification process are high enough for sterilization.
The uplifting of the beds cools them enough for colonization by microbes and fractures and faults provide inoculation pathways by the infiltration of surface water.
Isotopic data from wells in the Zonguldak basin suggest that the methane is primarily thermogenic in nature.
Reinoculation is supported by the evidence of isotopically lighter gas occurring near cleats in the coal beds.
This is in corroboration with the Ro values that suggest thermogenic production of methane in the Zonguldak basin would have been high.
[1] The total volume of coal bed methane in the Karadon Formation in the Amasra region has been estimated to be 862.5–2600 million cubic metres.