Using geophysical logs to identify Milankovitch cycles and to calculate net primary productivity (NPP) of the Late Permian coals, western Guizhou, China

Journal of Palaeogeography

Table 2 Summary of peatland net primary productivity (NPP) levels at different geological ages and latitudes

Geological age	Latitude	NPP (g⋅C⋅m⁻²⋅a^− 1)	CO₂ content (%)	O₂ content (%)
P₃–1
Late Permian	0°–(−10)°S	^b217.2–462	0.1	28
P₃–2
Late Permian	0°–(−10)°S	242–433.8	0.1	28
^aP₃–1
Late Permian	40°–45°N	112–243	0.1	28
^aP₃–2
Late Permian	40°–45°N	143.5–202	0.1	28
J₂
Middle Jurassic	42°–44°N	256.7–307.1	0.1	14.6
K₁
Early Cretaceous	40°–45°N	231–256	0.15	21
Q
Holocene	40°–45°N	150–230	0.03	21

P₃–1, P₃–2, J₂, K₁ and Q refer to Fig. 7 for the approximate time positions of peatlands formed during geologic time
^a means the converted value from the original tropics to a middle latitude area
^b represents the new estimated NPP value based on the long-term average carbon accumulation rate for peatland (Wang et al. 2011)