Editing Permian–Triassic extinction event (section)

==== Coal gap{{anchor|Coal Gap}} ====
No [[coal]] deposits are known from the Early Triassic, and those in the Middle Triassic are thin and low-grade. This "coal gap" has been explained in many ways. It has been suggested that new, more aggressive fungi, insects, and vertebrates evolved and killed vast numbers of trees. These [[decomposer]]s themselves suffered heavy losses of species during the extinction and are not considered a likely cause of the coal gap. It could simply be that all coal-forming plants were rendered extinct by the P–Tr extinction and that it took 10&nbsp;million years for a new suite of plants to adapt to the moist, acid conditions of [[peat]] [[bogs]].<ref name="Retallack1996" /> [[Abiotic]] factors (factors not caused by [[organism]]s), such as decreased rainfall or increased input of [[Clastic rock|clastic sediments]], may also be to blame.<ref name="McElwain2007" />

On the other hand, the lack of coal may simply reflect the scarcity of all known [[sediment]]s from the Early Triassic. Coal-producing [[ecosystem]]s, rather than disappearing, may have moved to areas where we have no sedimentary record for the Early Triassic.<ref name="McElwain2007" /> For example, in eastern Australia a cold climate had been the norm for a long period, with a peat [[Bog|mire]] ecosystem adapted to these conditions.<ref>{{cite journal |last1=Retallack |first1=Gregory J. |date=1 January 1999 |title=Postapocalyptic greenhouse paleoclimate revealed by earliest Triassic paleosols in the Sydney Basin, Australia |url=https://pubs.geoscienceworld.org/gsa/gsabulletin/article-abstract/111/1/52/183439/Postapocalyptic-greenhouse-paleoclimate-revealed |journal=[[Geological Society of America Bulletin]] |volume=111 |issue=1 |pages=52–70 |doi=10.1130/0016-7606(1999)111<0052:PGPRBE>2.3.CO;2 |access-date=31 May 2023|url-access=subscription }}</ref> Approximately 95% of these peat-producing plants went ''locally'' extinct at the P–Tr boundary;<ref>{{cite journal |last=Michaelsen |first=P. |year=2002 |title=Mass extinction of peat-forming plants and the effect on fluvial styles across the Permian–Triassic boundary, northern Bowen Basin, Australia |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=179 |issue=3–4 |pages=173–188 |bibcode=2002PPP...179..173M |doi=10.1016/S0031-0182(01)00413-8}}</ref> coal deposits in Australia and Antarctica disappear significantly ''before'' the P–Tr boundary.<ref name="McElwain2007" />