science

Oliní Group

Oliní Group is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Oliní Group rather than just read about it. In short: The Oliní Group (Spanish: Grupo Oliní, K3k5o, K2ol, Kso) is a fossiliferous geological group of the VMM, VSM and the eastern flanks of the Central and western flanks of the Eastern Ranges of the Colombian Andes. The regional group stretches from north to south across approximately 700 kilometres (430 mi) and dates to the Late Cretaceous period; Coniacian, Santonian and Campanian epochs, and has a maximum thickness o…

Key takeaways

Oliní Group belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Oliní Group to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Oliní Group from memory before moving on to harder problems.

Reference excerpt

The Oliní Group (Spanish: Grupo Oliní, K3k5o, K2ol, Kso) is a fossiliferous geological group of the VMM, VSM and the eastern flanks of the Central and western flanks of the Eastern Ranges of the Colombian Andes. The regional group stretches from north to south across approximately 700 kilometres (430 mi) and dates to the Late Cretaceous period; Coniacian, Santonian and Campanian epochs, and has a maximum thickness of 287 metres (942 ft). Fossils of Eonatator coellensis have been found in the unit, near Coello, Tolima.

Etymology The group was named in 1954 by Peters, and redefined by De Porta in 1965. The group was named after Quebrada Oliní in Chaparral, Tolima.

Subdivisions The Oliní Group is a geological group usually described as a whole due to the problematic lateral continuity, although in other cases the individual formations forming the group are used. Earlier names used were Lower Chert member, Upper Sandstone Member and Upper Chert member. According to Acosta and Ulloa (2002), the group is subdivided into, from bottom to top:

Lower Lydite Formation Native name - Spanish: Formación Lidita Inferior (Ksli) Definition - Cáceres and Etayo (1969) Age - early Coniacian Thickness - 150 metres (490 ft) Lithologies - radiolarites (lydites), chert and siliceous siltstones Fossil content - Globigerina cretacea, Inoceramus peruanus, Texanites aff. serratomarginatus Depositional environment - anoxic pelagic

Claystone Level Native name - Spanish: Nivel de Lutitas (Ksl, Ksom) Definition - De Porta (1965) Age - Santonian Thickness - 100 metres (330 ft) Lithologies - siltstones, calcareous and siliceous mica-bearing mudstones intercalated by thick banks of fine sandstones and sporadic shaly limestones Fossil content - Bulimina compreza, Dentalina lorneiana, Haplophragmoides excavata, Anomalina redmondi, Dicarinella asymetrica, D. concavata, Rosita fornicata Depositional environment - platform

Upper Lydite Formation Native name - Spanish: Formación Lidita Superior (Ksls) Definition - De Porta (1965) Age - Campanian Thickness - 100 to 114 metres (328 to 374 ft) Lithologies - calcareous siltstones, chert, radiolarites and micritic limestones with thin beds of conglomerates Fossil content - Wheelerella, Sporobulimina, Siphogenerinoides, Globirinelloides praeriehillensis, Rugoglobigerina sp., Globotruncana aff. insignis?, G. ?ventricosa Depositional environment - outer platform

Paleontology

Fossils of the mosasaur Eonatator coellensis were found near Coello, Tolima in the Oliní Group.

Stratigraphy and depositional environment The Oliní Group conformably overlies the Loma Gorda Formation of the Güagüaquí Group and is overlain by the Cimarrona Formation in the VMM, the Córdoba Formation in the Guaduas Syncline and the La Tabla Formation near Tocaima and in Huila and Tolima. The age has been estimated on the basis of ammonites to be ranging from Coniacian to Campanian. Stratigraphically, the lower part of the formation is time equivalent with the upper part of the Chipaque Formation and the Conejo Formation, while the upper portion correlates with the La Luna Formation and Guadalupe Group. The Oliní Group was deposited in a relative high sea level environment in an outer platform setting, following a sequence boundary, forming the base of the unit. The radiolarites of the Upper Lydite Formation represent a maximum flooding surface.

Outcrops

The type locality of the Oliní Group is Quebrada Oliní in Chaparral, Tolima. The group is furthermore found over a large stretch in the eastern Central and western Eastern Ranges of Colombia, bordering the Magdalena River on both sides. The group crops out to the northwest of Vélez in the hanging wall of the El Minero Fault, around Caparrapí, in the footwall of the El Cámbulo Fault between Útica and Guaduas and in the Bituima Synclinal, where it is cross-cut by the Vianí Fault and occurs in the hanging wall of the Alto del Trigo Fault, in the heavily faulted banks of the Magdalena River surrounding Guataquí and northwest of Coello and in the Eastern Ranges cross-cut by the Sumapaz River northeast of Ricaurte, in the hangingwall of the Salcedo Fault to the west of Apulo, on both sides of the Cucuana River near Ortega, in both the hangingwall and footwall of the El Páramo Fault east and south of Carmen de Apicalá and in the hangingwall of the Prado Fault, the hangingwall of the Quinini Fault west and south of Icononzo, the footwall of the La Pava Fault east and southeast of Chaparral, in the footwall and hangingwall of the Altamizal Fault east of Dolores, east and west of the Prado Reservoir near Prado, in the footwall and hangingwall of the Chusma Fault, west of Aipe, east of Alpujarra, in the footwall of the Baché Fault in Palermo, offset by the Picarní and San Andrés Faults, north of Yaguará, east of La Plata, Huila, and the southernmost exposure is found in Naranjal, where the group is emplaced by the Altamira Fault.

Illustrations

Worked examples

Example 1 — a first encounter with Oliní Group

Start with the simplest possible case. Write down what Oliní Group claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Oliní Group before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Oliní Group ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Oliní Group

In research: Oliní Group appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Oliní Group in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Oliní Group is common in secondary-school and first-year university syllabi. It links to neighbouring topics Campanian Stage, Chert groups, Conglomerate groups, so understanding it makes those chapters shorter.
In everyday life: Look for Oliní Group outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Oliní Group in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Oliní Group means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Oliní Group out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Oliní Group in simple terms?

Why does Oliní Group matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Oliní Group?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Oliní Group.