The island of Aruba formed within the past 145 million years, beginning in the Cretaceous, as part of the Lesser Antilles island arc. The island is built on a thick sequence of volcanic rock, but also has carbonate sediment deposits because it was submerged for parts of its existence. [2]
The three kilometer thick Aruba Lava Formation is the oldest unit on the island, from the Cretaceous, which is intruded by a tonalite pluton. Older geologic research referred to this unit as the Diabase-Schist-Tuff Formation. Although mainly basalt, it also includes volcaniclastic conglomerate, dolerite, chert and chert limestone. Small sedimentary inclusions preserve ammonite fossils, suggesting it formed during the Turonian, while rubidium-strontium dating gives an age of 85 to 70 million years ago. Remnant pillow lava and sheet-flows record ancient eruptions, flowing down to and often cooling very quickly in seawater. The intrusion of the pluton caused contact metamorphism in some of the surrounding basalt and left behind epidote, hornblende, albite and uralite in the rocks. Geochemists have found that the major and trace element chemistry of the rocks is almost the same as in Curaçao.
The hornblende tonalite batholith is a major part of Aruba's geology. The "roof" of the formation is made out of the oldest intrusive material, norite and gabbro. The norite shifts from hypersthene to augite while the gabbro has abundant augite, hornblende and quartz. The tonalite is mainly plagioclase, interstitial quartz and potassium feldspar as well as dark minerals like hornblende, biotite, clinopyroxene and magnetite. There are also small occurrences of trondhjemite. [3]
A small outcrop of Eocene and Oligocene limestone occurs at Butucu Ranch in east-central Aruba, without quartz, but containing fossils from the time period such as algae and foraminifera. Named for exposures on Curaçao, the Neogene Seroe Domi Formation is on the southeastern side of Aruba and includes a series of detrital limestone and conglomerates. [4]
In 1942, two French friars using divining rods instructed a team to drill the Oranjestad borehole down 302 meters, which revealed the Oranjestad sands and clays from the Pliocene and Late Miocene, as well as a hypersaline artesian well. [5] Five limestone terraces formed during the past 2.5 million years of the Quaternary. [6]
Gabbro is a phaneritic (coarse-grained), mafic intrusive igneous rock formed from the slow cooling of magnesium-rich and iron-rich magma into a holocrystalline mass deep beneath the Earth's surface. Slow-cooling, coarse-grained gabbro is chemically equivalent to rapid-cooling, fine-grained basalt. Much of the Earth's oceanic crust is made of gabbro, formed at mid-ocean ridges. Gabbro is also found as plutons associated with continental volcanism. Due to its variant nature, the term gabbro may be applied loosely to a wide range of intrusive rocks, many of which are merely "gabbroic". By rough analogy, gabbro is to basalt as granite is to rhyolite.
The geography of Aruba, located at the juncture of the South American and Caribbean tectonic plates, has been shaped by a complex interplay of geological processes. From its flat expanses to its rugged coastlines, Aruba's geography and geology reveal the island's geographical diversity and its underlying geological formations, offering a comprehensive understanding of Aruba's terrain and environmental dynamics of this Caribbean destination.
Pyroxenite is an ultramafic igneous rock consisting essentially of minerals of the pyroxene group, such as augite, diopside, hypersthene, bronzite or enstatite. Pyroxenites are classified into clinopyroxenites, orthopyroxenites, and the websterites which contain both types of pyroxenes. Closely allied to this group are the hornblendites, consisting essentially of hornblende and other amphiboles.
Hooiberg ) is a distinctively shaped, 165 m (541 ft) conical hill located at the heart of the island of Aruba. This geological volcanic formation is a prominent and recognizable landmark that has long captured the attention of locals and visitors alike—Hooiberg is Aruba's centerpiece.
Ayo Rock Formations are monolithic rock boulders located on the island of Aruba in the Caribbean, near Ayo village and about 3.2 km (2.0 mi) from the defunct natural bridge towards Casibari. Similarly, the Casibari Boulders are about 3.2 km (2.0 mi) inland between Natural Bridge and Oranjestad, the capital of Aruba, to the west of Boca Andicuri.
Granite Mountain is a 7,628-foot (2,325 m) mountain located in Yavapai County, Arizona that covers roughly 12 square miles (31 km2). It was once known as Mount Gurley, for the first governor of the Arizona Territory, John A. Gurley. Its southwest face has a sheer granite cliff approximately 500 feet high that is one of the best locations for rock climbing in the state of Arizona. It is located in the Granite Mountain Wilderness, which is managed as a part of the Prescott National Forest. The mountain stands at the northern end of the Sierra Prietas, and borders Skull Valley on the west, on the northwest by the Santa Maria Mountains, and east by the Williamson Valley.
Jamanota is a hill situated within Aruba's Arikok National Park, reaching a height of 188 metres (617 ft) and holding the distinction of being the highest point on the island. Jamanota is a word from the Arawak language and can be explained somewhat as follows: JA or YA is spirit; MA is great or great spirit; NO is a suffix denoting a plural; TA is source. So about, Source of Great Spirits.
Megalomys curazensis is a species of rodent from the Late Pleistocene of the island of Curaçao, off northwestern Venezuela. It is a member of the genus Megalomys, which also includes species from other islands of the Lesser Antilles. It is known from abundant but fragmentary material found throughout the island.
Curaçao, as well as the rest of the ABC islands and Trinidad and Tobago, lies on the continental shelf of South America. It is a thin island with a generally hilly topography; the highest point is Christoffelberg 372 m (1,220 ft) in the northwest. The coastline's bays, inlets and hot springs offer a source of natural minerals, thermal conditions, and seawater used in hydrotherapy and mesotherapy, making the island one of many balneoclimateric areas in the region. Off the southeast coast lies the small, flat island of Klein Curaçao.
The island of Bonaire began to form as part of the Lesser Antilles island arc in the past 145 million years, beginning in the Cretaceous. The island has been submerged or partially submerged for much of its existence, forming large limestone and sedimentary rock formations, atop a thick basement of volcanic rocks.
The island of Curaçao began to form within the past 145 million years, beginning in the Cretaceous, as part of the Lesser Antilles island arc. Because the island was submerged for large parts of its history, reef environments formed atop thick layers of mafic volcanic rock, producing carbonate sedimentary rocks.
The geology of the Democratic Republic of the Congo is extremely old, on the order of several billion years for many rocks. The country spans the Congo Craton: a stable section of ancient continental crust, deformed and influenced by several different mountain building orogeny events, sedimentation, volcanism and the geologically recent effects of the East Africa Rift System in the east. The country's complicated tectonic past have yielded large deposits of gold, diamonds, coltan and other valuable minerals.
The geology of Bosnia & Herzegovina is the study of rocks, minerals, water, landforms and geologic history in the country. The oldest rocks exposed at or near the surface date to the Paleozoic and the Precambrian geologic history of the region remains poorly understood. Complex assemblages of flysch, ophiolite, mélange and igneous plutons together with thick sedimentary units are a defining characteristic of the Dinaric Alps, also known as the Dinaride Mountains, which dominate much of the country's landscape.
The geology of the U.S. Virgin Islands includes mafic volcanic rocks, with complex mineralogy that first began to erupt in the Mesozoic overlain and interspersed with carbonate and conglomerate units.
The geology of Uzbekistan consists of two microcontinents and the remnants of oceanic crust, which fused together into a tectonically complex but resource rich land mass during the Paleozoic, before becoming draped in thick, primarily marine sedimentary units.
The geology of Italy includes mountain ranges such as the Alps and the Apennines formed from the uplift of igneous and primarily marine sedimentary rocks all formed since the Paleozoic. Some active volcanoes are located in Insular Italy.
The geology of Costa Rica is part of the Panama Microplate, which is slowly moving north relative to the stable Caribbean Plate.
The geology of Guatemala encompasses rocks divided into two tectonic blocks. The Maya Block in the north has igneous and metamorphic North American Craton basement rocks, overlain by late Paleozoic metasedimentary rocks, which experienced deformation during the Devonian. Red beds, evaporites and marine limestone from the Mesozoic overlie these rocks. A karst landscape formed in the thick limestone units across the north of the country. During a collisional orogeny, these Paleozoic and Mesozoic rocks were uplifted, thrust and folded as the Central Guatemalan Cordillera. Paleogene rocks from the early Cenozoic include volcanic and marine clastic rocks, associated with high rates of erosion.
The geology of Yukon includes sections of ancient Precambrian Proterozoic rock from the western edge of the proto-North American continent Laurentia, with several different island arc terranes added through the Paleozoic, Mesozoic and Cenozoic, driving volcanism, pluton formation and sedimentation.
