Maya Lowlands

The Maya Lowlands are the largest cultural and geographic, first order subdivision of the Maya Region, located in eastern Mesoamerica.

Extent
The Maya Lowlands are restricted by the Gulf of Mexico to the north, the Caribbean Sea to the east, and the Maya Highlands to the south and west. The precise northern and eastern limits of the Lowlands are widely agreed upon, being formed by conspicuous bodies of water. Their southern and western limits, however, are not precisely fixed, as these are restricted by 'subtle environmental changes or transitions from one zone [the Highlands] to another [the Lowlands],' rather than conspicuous geographic features.

The Lowlands fully encompass Belize, the Guatemalan department of Peten, and the Mexican states of Campeche, Yucatán, and Quintana Roo. They may further partially encompass a number of northerly Guatemalan departments, northwesterly Honduran departments, and southeasterly Mexican states.

Divisions
The Lowlands are usually subdivided either into northern and southern regions, or into northern, central, and southern regions. As with the Lowlands–Highlands border, the boundaries of the Lowlands' internal subdivisions are not precisely fixed, being rather formed by gradual environmental or climatic transitions.

Northern
The Northern Lowlands are generally characterised by relatively low rainfall and high temperatures, typically ranging within 20 - 80 in per annum and 77 - 95 F, respectively. Their rainy season typically lasts six or seven months during June–December, with a subsequent six- or five-month dry season. Their terrain is predominated by tropical forests in the south, gradually giving way to low bush-and-scrub forests in the north. Prominent bodies of water include Lake Bacalar and various cenotes. Prominent groupings of archaeological sites within the Northern Lowlands include the Northern Plains, the East Coast, the Puuc, and the Chenes sites.

The Northern Lowlands generally encompass portions of Campeche, Yucatán, and Quintana Roo in Mexico.

Central
The Central Lowlands are generally characterised by relatively low rainfall and high temperatures, typically ranging about 80 in per annum and 77 - 95 F, respectively. Their rainy season typically lasts eight-and-a-half months, from mid-May to January, with a subsequent dry season of three-and-a-half months, from February to mid-May. Their terrain is predominated by low east–west ridges of folded and faulted limestone, covered by tropical forests, grasslands, and wetlands. Prominent bodies of water include the Hondo, New, and Belize Rivers and their tributaries, and a roughly 910 mi2 drainage basin in central Peten housing some fourteen lakes, the largest of which is Lake Peten Itza. Prominent groupings of archaeological sites within the Central Lowlands include the Belize River Valley and the Central Peten Lakes.

The Central Lowlands generally encompass portions of Peten in Guatemala, Campeche and Quintana Roo in Mexico, and Cayo, Belize [District], Orange Walk, and Corozal in Belize.

Southern
The Southern Lowlands are generally characterised by relatively high rainfall and temperatures, typically ranging within 80 - 120 in per annum and 77 - 95 F, respectively. Their rainy season ranges between nine and eleven months, with the dry season compressed to three months or fewer, with the latter typically occurring during March–May. Their terrain ranges from broken karst topography, predominated by rain-forest and limestone formations, to low-lying coastal topography, predominated by swamps. Prominent bodies of water within the Southern Lowlands, which often feature relatively deep and fertile soils, include the Usumacinta River and its tributaries, the Sarstoon River, Lake Izabal, the Rio Dulce, the alluvial valley of the lower Motagua, and the Chamelecon and Ulua Rivers. Prominent groupings of archaeological sites within the Southern Lowlands include the Southern Belize Region.

The Southern Lowlands generally encompass portions of Chiapas, Tabasco, and Campeche in Mexico, Huehuetenango, El Quiche, Alta Verapaz, Izabal, and Peten in Guatemala, Cayo, Stann Creek, and Toledo in Belize, and Cortes, Santa Barbara, and Copan in Honduras.

Physical
The Lowlands are generally characterised by elevations below 1000 - 2625 ft and a hot, tropical climate. They are predominantly covered by evergreen tropical forests, which tend to grow taller and denser in the southern Lowlands, given increased rainfall in this area, compared to the northern Lowlands, which experience relatively less rainfall. The climate of the eastern coasts is made relatively warmer and more humid by the Atlantic North Equatorial Current and the Gulf Stream.

Human
The Lowlands have been deemed the 'most central [subdivision of the Maya Region] to the story of Maya civilisation,' with tentative estimates placing the region's population in circa AD 800 at 2–10 million, and 17 of the largest 19 ancient Maya cities located in the region.

Climate
The Lowlands are characterised by a hot, tropical climate, and are thus traditionally known as tierra caliente in Spanish. The area experiences two seasons, wet and dry ones, with rainfall during the wet season usually peaking in June and October. Mean annual rainfall typically ranges within 20 - 120 in, with temperatures typically within 77 - 95 F.

Scholars have traditionally assumed that the Lowlands' present-day climate had 'always been the same, all through Maya prehistory and history,' but palaeoclimatic research has 'challenged this assumption, revealing far more climatic fluctuation than previously anticipated.' In particular, climate proxies from Quintana Rooan lakes and Belizean caves have provided 'a continuous record of climate changes for the Maya Lowlands extending over a period of 3,500 years.' These have revealed, for instance, particularly severe or prolonged droughts during AD 200–300, 420, 820–870, 930, and 1020–1100, some of which are thought to have played a part in the collapse of various ancient cities.

Provinces
The Lowlands are thought to fully or partially encompass at least eleven geologic provinces. Notably, the northern and central Lowlands 'encompass the most extensive karstlands of the North American continent' i.e. the Yucatán Platform.

Basins
The Lowlands are believed to fully or partially comprehend at least four sedimentary basins.

Tectonics
The Lowlands lie wholly within the Maya Block of the North American Plate. They notably house the Ticul Fault to the north, the Rio Hondo, Yucatán Channel, and Maya Mountain Faults to the east, and a portion of the Motagua–Polochic Fault Zone to the south.

Stratigraphy
In the northern and central Lowlands, encompassed within the Yucatán Platform, mean crustal thickness increases from 12–16 miles (20–25 km) in the north to 19–25 miles (30–40 km) in the south. These portions of the Lowlands are blanketed by a carbonate sedimentary cover reaching a mean thickness of up to some 4 miles (6 km).