Caviana (Portuguese: Ilha Caviana, formerly in Aruã language: Uyruma) is a coastal island in the Brazilian state Pará. The island is part of the Amazon Delta. In the 17th and 18th Century it was the stronghold of the Aruã people. From the island a tidal bore called the pororoca can be observed. Between 1845 and 1850, a strong pororoca split the island into two parts, called Inner and Outer Caviana.
Location
Administratively, Caviana is part of the municipality Chaves in the Brazilian state Pará. The Equator runs through Outer Caviana, as does the 50th meridian west. It is the third-largest island in the Amazon Delta, after Marajó and Ilha Grande de Gurupá.
The island belongs to the Marajó Archipelago. It is located in the delta lowlands at the mouth of the Amazon, between the north coast of Marajó Island and the coast of Amapá. It is surrounded by Janaucu and Jarupari in the north, Mexiana in the east and the Jurupari Archipelago in the west. It is separated from Mexiana by the Canal Perigoso ("Dangerous Channel"), called such because sandbanks and strong winds make navigation perilous during low tides. During the Tertiary epoch, Marajó, Caviana and Mexiana were connected to each other and to the mainland, forming a wide interfluve between the Amazon and Tocantins rivers. The continuity of the Barreiras Formation along the three islands is evidence of this, as are some palaeochannels that form continuous lines between them. The islands became separated through tectonic action during the Flandrian transgression at the beginning of the Holocene, some 12,000 years ago.
Caviana is located in an area where the strong current of the Amazon River meets the opposing pressure of the Atlantic waters, causing extreme turbulence, erosion, landslides and sedimentation. This encounter of water currents causes a distinctive tidal bore, which is called the pororoca. Caviana is known as a place to observe the pororoca and for some to surf on it.
The dynamism of wind, tides and currents gives rise to frequent changes in the topography of the Amazon Delta. Shorelines can change due to rapid sedimentation and erosion processes, and islands can split up or join together. On Caviana, this can be noted through the names by which local inhabitants refer to certain parts of the island, such as Ilha Nova or Ilha da Prainha (ilha = island), indicating that that these areas have been separate islands in the past, but have joined up with Caviana at some point.
- The smaller part with an area of is called Inner or Northern Caviana (Caviana de Dentro or Caviana Setentrional)
- The larger part with an area of is called Outer or Southern Caviana (Caviana de Fora or Caviana Meridional).
Nature
[[File:Caviana natural.png|thumb|300px|Natural features of Outer Caviana
Caviana is a birdwatchers' haven. As many as 145 different species were observed here. The ornithologist Joseph B. Steere observed the birds on the island in 1871, specimens were brought to the University of Michigan Museum of Natural History.
The island is contained in the Marajó Archipelago Environmental Protection Area, a sustainable-use conservation unit established in 1989 to protect the environment of the region.
Archeology
thumb|300px|Map of Outer Caviana showing the location of archeological sites ([[teso (archeological site)|tesos). The location of Rebordello has been labelled. The period in which these first groups settled on the island hasn't definitively been determined. Polychrome ceramics found from this phase are similar to those found in the north and south-east of the current state Amapá, suggesting this region as their origin.
The second phase of settlement, which extended into colonial times, is associated with the Aruã. Evidence found in the tesos indicates that they had much in common with other Arawak groups. This is apparent in the alignment of stones, polished statuettes, nephrite beads and amulets, ceramic figures, plates and roasters with dotted decoration.
History
thumb|upright=.8|Map from 1854 of the port of Rebordello (then already abandoned)
In 17th and 18th Century, the Aruã made Caviana their stronghold. They called the island Uyruma, and lived mostly on its eastern coast. Their chief in the mid of the seventeenth century was called Piyé. They called their main settlement Piyé's Village (Aldeia de Piyé) after him, until it was renamed Rebordello by the Portuguese. In 1763 the village suffered a fire.