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Why did coal swamps develop near the Equator during the Pennsylvanian Subperiod?

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Carboniferous paleogeography — Carboniferous Period Distribution of landmasses, mountainous regions, shallow seas, and deep ocean basins during the late Carboniferous Period. Included in the paleogeographic reconstruction are the locations of the interval's subduction zones.

During the Pennsylvanian Subperiod, coal swamps developed near the Equator primarily due to the prevailing tropical climate and specific geological conditions that favored the accumulation of plant material.12

The equatorial regions were characterized by tropical conditions, which supported the growth of abundant terrestrial flora. As sea-level cyclicity became more pronounced during the Pennsylvanian, these equatorial settings transitioned from carbonate shelves to coal basins. The formation of these coal deposits was closely linked to deltaic conditions; as shallow seas advanced and retreated, they created delta plains where swamp environments could flourish.134

These swamps allowed for the accumulation of vast amounts of plant debris, which, through the process of carbonization and compaction, formed thick coal seams. Unlike flora in higher latitudes, which exhibited seasonal growth rings due to cooler climates, the plants in these equatorial coal swamps lacked such rings, reflecting the consistent, warm tropical environment of the region.41