Aruba’s Cretaceous geology, rock art and wetlands

Two journal papers set out different age interpretations for Aruba’s intrusive rocks. The 1978 study places the northwest tonalite at 85.1 ± 0.5 million years and the rest at 70.4 ± 2.0 million years, treating these dates as evidence of two intrusion episodes. For the crystalline core, the 1986 authors propose an oceanic-arc origin. In their account, that crust collided in the Santonian with the passive margin along northern South America. Their age estimate for the composite tonalite-and-gabbro batholith is 88.5 ± 0.8 million years. VisitAruba.com lists Hooiberg at 165 metres and uses “Hooibergiet” for a quartz-diorite variety; Aruba.com’s Casibari page identifies the local boulders as tonalite.[2][1][3][4]

Published accounts connect Aruba’s rock art to a longer island chronology. The Rijksmuseum van Oudheden places mainland-settlement traces about 3,500 years ago and Caquetío arrivals from Venezuela around 900–1000 CE; it links the paintings to the period when both communities were active. A 2023 AAN report about Sjoerd Martens’s book relays archaeologist Harold Kelly’s count of 458 documented images—456 paintings and two carved petroglyphs—and radiocarbon ranges for one example each at Arikok (776–1018 CE) and Ayo (1043–1275 CE). The report’s summary of Kelly’s palette distinguishes limestone caves, where paintings are nearly all red, from formations with red or white images; it also notes black examples at Rooi Taki. Archaeology’s 2014 profile contrasts the animal and bird figures by the Cunucu Arikok path with more elaborate human scenes on a nearby dolerite outcrop. Aruba.com’s caves page identifies Fontein as the cave with Arawak ceiling drawings.[5][6][7][8]

These two Ramsar entries describe different wetland boundaries. Western Wetlands groups five saliña areas across 392 hectares; Spanish Lagoon covers 259 hectares after a 2023 enlargement from 90 hectares that added the central wetland’s catchment. Ramsar lists the lagoon’s designation date as 23 May 1980. Tidal flats and mangroves surround the lagoon, and Ramsar gives its narrow coastal inlet as about two kilometres long and 200–500 metres wide. The listing names Atlantic tarpon (Megalops atlanticus), cubera snapper (Lutjanus cyanopterus) and hogfish (Lachnolaimus maximus) as nursery users; it identifies hogfish as globally vulnerable. For the Western Wetlands, the Ramsar sheet describes saliñas as coastal marshes outside regular tidal exchange where seawater occasionally mixes with fresh water, changing salinity levels. It also records Cnemidophorus arubensis, the endemic Aruba whiptail.[9][10]