|Tobago Volcanic Group|
|Stratigraphic range: Albian|
|Other||Shale, sandstone, siltstone|
|Country||Trinidad and Tobago|
The Tobago Volcanic Group is a geologic group in Trinidad and Tobago. It preserves radiolaria and ammonite fossils dating back to the Albian period. The formation contains the Bacolet Formation and comprises organic-rich, black pyritic siliceous mudstones and fine-grained volcaniclastic sandstones and siltstones.
Trinidad and Tobago is an archipelagic republic in the southern Caribbean between the Caribbean Sea and the North Atlantic Ocean, northeast of Venezuela. They are southeasterly islands of the Lesser Antilles, Monos, Huevos, Gaspar Grande, Little Tobago, and St. Giles Island. Trinidad is 11 km (6.8 mi) off the northeast coast of Venezuela and 130 km (81 mi) south of the Grenadines. The island measures 4,768 km2 (1,841 sq mi) in area with an average length of 80 km (50 mi) and an average width of 59 km (37 mi). The island appears rectangular in shape with three projecting peninsular corners. Tobago is 30 km (19 mi) northeast of Trinidad and measures about 298 km2 (115 sq mi) in area, or 5.8% of the country's area, 41 km (25.5 mi) in length and 12 km (7.5 mi) at its greatest width. The island is cigar-shaped in appearance, with a northeast–southwest alignment.
The Lesser Antilles are a group of islands in the Caribbean Sea. Most of them are part of a long, partially volcanic island arc between the Greater Antilles to the north-west and the continent of South America. The islands of the Lesser Antilles form the eastern boundary of the Caribbean Sea where it meets the Atlantic Ocean. Together, the Lesser Antilles and the Greater Antilles make up the Antilles. The Lesser and Greater Antilles, together with the Lucayan Archipelago, are collectively known as the West Indies.
A volcanologist, or volcano scientist, is a geologist who focuses on understanding the formation and eruptive activity of volcanoes. Volcanologists frequently visit volcanoes, sometimes active ones, to observe and monitor volcanic eruptions, collect eruptive products including tephra, rock and lava samples. One major focus of inquiry in recent times is the prediction of eruptions to alleviate the impact on surrounding populations and monitor natural hazards associated with volcanic activity. Geologists who research volcanic materials that make up the solid Earth are referred to as igneous petrologists.
Trinidad is the larger and more populous of the two major islands of Trinidad and Tobago. The island lies 11 km (6.8 mi) off the northeastern coast of Venezuela and sits on the continental shelf of South America. It is often referred to as the southernmost island in the West Indies. With an area of 4,768 km2 (1,841 sq mi), it is also the fifth largest in the West Indies.
The Northern Range is the range of tall hills across north Trinidad, the major island in the Republic of Trinidad and Tobago. The hills range from the Chaguaramas peninsula on the west coast to Toco in the east. The Northern Range covers approximately twenty-five percent of the land area of Trinidad.
Tunapuna–Piarco is one of the 9 regions of Trinidad and Tobago. It is the most populous region in the country by total population and the fifth-largest by total land area. Geographically located in Northern Trinidad, Tunapuna–Piarco shares its borders with the regions of San Juan–Laventille to the west, Couva–Tabaquite–Talparo to the south, the Borough of Chaguanas to the south-west, Sangre Grande to the east and the Caribbean Sea to the north. The region also completely surrounds the Royal Chartered Borough of Arima, which is located in the south-eastern corner of the region.
The Austin Chalk is an upper Cretaceous geologic formation in the Gulf Coast region of the United States. It is named after type section outcrops near Austin, Texas. The formation is made up of chalk and marl.
The Britton Formation is a geologic formation deposited during the Middle Cenomanian to the Early Turonian ages of the Late Cretaceous in modern-day East Texas. It forms the lower half of the Eagle Ford Group in the northern portion of East Texas. The formation was named by W. L. Moreman in 1932 for outcrops on Mountain Creek near the small town of Britton, south of Dallas. In the Dallas area it has been subdivided into the Six Flags Limestone, Turner Park Member, and Camp Wisdom Member. The Six Flags Limestone is a 3 ft thick fossiliferous calcarenite made up of pieces (prisms) of Inoceramus clams. The Turner Park and Camp Wisdom Members were subdivided based on the numerous volcanic ash beds (bentonites) found in the Turner Park, and the common occurrence of concretions in the Camp Wisdom. They are approximately 120 ft and 250 ft thick in the Dallas area. Thin sandstones known as the Templeton Member are found in Grayson County, north of Dallas, that are age equivalent to the lower part of the Turner Park Member. The Templeton Member was originally described as a part of the Woodbine, but it was recently placed in the Britton Formation of the Eagle Ford Group based on its age as derived by ammonites. Plesiosaur remains are among the vertebrate fossils that have been recovered from its strata.
Hoplitoides is an ammonite from the Upper Cretaceous, Turonian belonging to the Coilopoceratidae, a family in the Acanthoceratoidea. Hoplitoides have early whorls which are grooved, then flat, and finally narrowly rounded venters; early stages with umbilical tubercles and space ribs, later stages becoming smooth. The suture is similar to that of Coilopoceras but less extreme. Hoplitoides has an established distribution which is widespread, from western North America, northwestern Africa and northern South America.
Paleontology in Alaska refers to paleontological research occurring within or conducted by people from the U.S. state of Alaska. During the Late Precambrian, Alaska was covered by a shallow sea that was home to stromatolite-forming bacteria. Alaska remained submerged into the Paleozoic era and the sea came to be home to creatures including ammonites, brachiopods, and reef-forming corals. An island chain formed in the eastern part of the state. Alaska remained covered in seawater during the Triassic and Jurassic. Local wildlife included ammonites, belemnites, bony fish and ichthyosaurs. Alaska was a more terrestrial environment during the Cretaceous, with a rich flora and dinosaur fauna.
The Greenhorn Limestone or Greenhorn Formation is a geologic formation in the Great Plains Region of the United States, dating to the Cenomanian and Turonian ages of the Late Cretaceous period. The formation gives its name to the Greenhorn cycle of the Western Interior Seaway.
The Bacolet Formation is a geologic formation in Trinidad and Tobago. It preserves radiolaria and ammonite fossils dating back to the Albian period. The formation is part of the Tobago Volcanic Group and comprises organic-rich, black pyritic siliceous mudstones and fine-grained volcaniclastic sandstones and siltstones.
The Manzanilla Formation is a geologic formation in Trinidad and Tobago. It preserves fossils dating back to the Middle Miocene period.
The Matura Formation is a geologic formation in Trinidad and Tobago. It preserves bivalve and gastropod fossils dating back to the Pliocene period.
The Talparo Formation is a geologic formation in Trinidad and Tobago. It preserves fossils dating back to the Early Pliocene period.
The Nariva Formation is a geologic formation in Trinidad and Tobago. It preserves fossils dating back to the Paleogene period.
The Boca de Serpiente Formation is a geologic formation in Trinidad and Tobago. The limestones stained red with hematite, preserve fossils dating back to the Priabonian period.
The Morne Diablo Limestone is a geologic formation in Morne Diablo, Trinidad and Tobago. It preserves fossils dating back to the Oligocene period. The formation is laterally equivalent to the Cipero Marl and San Fernando Formation.
The geology of Trinidad and Tobago includes two different islands with different geological histories.