Piacenzian

Key takeaways

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

Reference excerpt

The Piacenzian is in the international geologic time scale the upper stage or latest age of the Pliocene. It spans the time between 3.6 ± 0.005 Ma and 2.58 Ma (million years ago). The Piacenzian is after the Zanclean and is followed by the Gelasian (part of the Pleistocene). The Piacenzian is roughly coeval with the European land mammal age MN 16, overlaps the late Chapadmalalan and early Uquian South American land mammal age and falls inside the more extensive Blancan North American land mammal age. It also correlates with the Astian, Redonian, Reuverian and Romanian regional stages of Europe, and the Waipipian and Mangapanian stages of New Zealand. Some authorities describe the British Red Crag Formation and Waltonian Stage as late Piacenzian, while others regard them as early Pleistocene. Carbon dioxide levels during the Piacenzian were similar to those of today, making this age, with global mean temperature 2–3 °C (3.6–5.4 °F) higher and sea levels about 20 metres (66 feet) higher than today, an important analogue for predictions of the future of our world.

Definition The Piacenzian was introduced in scientific literature by Swiss stratigrapher Karl Mayer-Eymar in 1858. It is named after the Italian city of Piacenza. The base of the Piacenzian is at the base of the Gauss chronozone and at the extinction of the planktonic forams Globorotalia margaritae and Pulleniatina primalis. The GSSP for the Piacenzian Stage is at Punta Piccola on Sicily, Italy. The top of the Piacenzian (the base of the Quaternary System and the Pleistocene Series) is defined magnetostratigraphically as the base of the Matuyama (C2r) chronozone (at the Gauss-Matuyama reversal), and isotopic stage 103. Above this point there are notable extinctions of the calcareous nannofossils: Discoaster pentaradiatus and Discoaster surculus.

Climate The Piacenzian was the last age before the Quaternary glaciations started to take hold in the Northern hemisphere. The ice sheet of Antarctica was also less prominent than today and sea levels were approximately 20 metres (66 feet) higher than the present. The global mean temperature was 2–3 °C (3.6–5.4 °F) warmer than the pre-industrial temperature. During the Mid-Piacenzian Warm Period the concentration of carbon dioxide peaked at approximately 389 ppm (in the range 381–427 ppm with 95% confidence), thus similar to the concentration during the 2010s. The Piacenzian can therefore be used as an analogue to the future climate and sea level to expect if the carbon dioxide concentration stabilizes at this level. In particular, the KM5c interglacial during the Mid-Piacenzian Warm Period occurred during an orbital configuration close to the current situation, with similar geographical distribution of solar insolation. Climate of the Piacenzian would have started as a somewhat wet and warm period in North America occurring just after a brief cooling period of the Zanclean. Deposition of sediments and mollusks of the Piacenzian correspond with the rise in sea level creating the Tamiami Subsea and Jackson Subsea of Florida, Duplin Subsea generally of South Carolina, and Yorktown Subsea of the Outer Banks and inland North Carolina. Dates have been established on the basis of the genera and species of mollusks found. In Namibia, the Piacenzian from 3.1 Ma onwards is associated with the spread of Renosterveld-like vegetation dependent on winter rainfall, which is attributable to a strong advection of polar waters along the coast of southwestern Africa and a northward shift of the Polar Front Zone in the Southern Ocean.

Origin of the genus Homo The late Piacenzian may be when the genus Homo developed out of the ancestral genus Australopithecus. While the oldest known fossils unambiguously identified as Homo habilis date to just after the end of the Piacenzian (2.58 Ma), a fossilized jawbone that exhibits traits that are transitional between Australopithecus and Homo habilis was discovered in the Afar Triangle in 2015. The find was made by Ethiopian student Chalachew Seyoum at a site called Ledi-Geraru between the Mille and Awash rivers, in Afar Regional State (near 11.36°N 40.86°E / 11.36; 40.86). Based on geological evidence from the Afar region, the individual would have lived just after a major climate shift, during which forests and waterways were rapidly replaced by arid savanna. Regarding the Afar region, and as stated in the journal Science: "Vertebrate fossils record a faunal turnover indicative of more open and probable arid habitats than those reconstructed earlier in this region, in broad agreement with hypotheses addressing the role of environmental forcing in hominin evolution at this time." This interpretation is consistent with hypotheses that emphasize the savanna as the ancestral environment which shaped the evolution of early Homo and other hominins.

References

Notes

Literature

Castradori, D.; Rio, D.; Hilgen, F. J.; Lourens, L. J. (1998). "The Global Standard Stratotype-section and Point (GSSP) of the Piacenzian Stage (Middle Pliocene)". Episodes. 21 (2): 88–93. doi:10.18814/epiiugs/1998/v21i2/003. Gradstein, F. M.; Ogg, J. G.; Smith, A. G., eds. (2005). A Geologic Time Scale 2004. Cambridge, UK: Cambridge University Press. doi:10.1017/CBO9780511536045. ISBN 0-521-78142-6. Rio, D.; Sprovieri, R.; Castradori, D.; Stefano, E. Di (1998). "The Gelasian Stage (Upper Pliocene): A new unit of the global standard chronostratigraphic scale". Episodes. 21 (2): 82–87. doi:10.18814/epiiugs/1998/v21i2/002. Thompson, R. S.; Fleming, R. F. (1996). "Middle Pliocene vegetation: reconstructions, paleoclimatic inferences, and boundary conditions for climate modeling". Marine Micropaleontology. 27 (1–4): 27–49. Bibcode:1996MarMP..27...27T. doi:10.1016/0377-8398(95)00051-8.

External links Piacenzian at the GeoWhen database Neogene timescale, at the website of the subcommission for stratigraphic information of the ICS Neogene timescale at the website of the Norwegian network of offshore records of geology and stratigraphy Piacenzian Microfossils: images of Piacenzian Foraminifera

Worked examples

Example 1 — a first encounter with Piacenzian

Start with the simplest possible case. Write down what Piacenzian claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In earth 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 Piacenzian 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 Piacenzian 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 Piacenzian

In research: Piacenzian appears in earth 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 Piacenzian 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: Piacenzian is common in secondary-school and first-year university syllabi. It links to neighbouring topics Geological ages, Piacenzian, Pliocene, so understanding it makes those chapters shorter.
In everyday life: Look for Piacenzian 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.

How to study Piacenzian in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Piacenzian 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 Piacenzian out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Piacenzian in simple terms?

The Piacenzian is in the international geologic time scale the upper stage or latest age of the Pliocene. It spans the time between 3.6 ± 0.005 Ma and 2.58 Ma (million years ago).

Why does Piacenzian matter?

Because it connects several earth 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 Piacenzian?

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 Piacenzian.