earth science

Jiangshanian

Jiangshanian is a earth 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 Jiangshanian rather than just read about it. In short: The Jiangshanian is the middle stage of the Furongian series. It follows the Paibian Stage and is succeeded by the still unnamed Stage 10 of the Cambrian.

Key takeaways

Jiangshanian 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 Jiangshanian to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Jiangshanian from memory before moving on to harder problems.

Reference excerpt

The Jiangshanian is the middle stage of the Furongian series. It follows the Paibian Stage and is succeeded by the still unnamed Stage 10 of the Cambrian. The base is defined as the first appearance of the trilobite Agnostotes orientalis which is estimated to be 494.2 million years ago. The Jiangshanian lasted until approximately 491 million years ago. The Jiangshanian stage was named after Jiangshan, a city in China's Zhejiang province, where its GSSP was defined.

Stratigraphy The Global boundary Stratotype Section and Point (GSSP) of the Jiangshanian is the "Duibian B Section" (28.815967°N 118.614933°E / 28.815967; 118.614933), west of the village of Duibian (碓边), and 10 km north of Jiangshan. The outcrop belongs to the Huayansi Formation (华严寺组). The upper boundary (the base of the Stage 10) is not formally defined by ICS, but there is a proposal to set the first appearance of an agnostoid Lotagnostus americanus as its marker. In 2012, international research group proposed the Kyrshabakty section in the Malyi Karatau Range, southern Kazakhstan, as a candidate for the Auxiliary boundary Stratotype Section and Point (ASSP) of the Jiangshanian. The proposal was approved by an overwhelming majority of votes by the International Subcommission on Cambrian Stratigraphy (ISCS). The section is situated near Kyrshabakty River, about 28 km north-east of the Zhanatas town. The first appearance datum (FAD) of Agnostotes orientalis is located at an altitude of 259 m above the base of the section, in the Zhumabay Formation, also known as Bestogai Formation. In 2021, the International Union of Geological Sciences (IUGS) proposed to deny the use of specific points and replace them by Standard Auxiliary Boundary Stratotypes (SABS) for more "flexible" correlations with GSSPs.

Major events At the beginning of the Jiangshanian, there was a peak in species diversity, comparable to that observed in the middle Guzhangian, before the Guzhangian–Paibian extinction. Jiangshanian extinction, which lasted approximately from 493.9 to 491.3 Ma, reduced species diversity by 55.2%. It was followed by an interval of relatively small fluctuations in species richness, which ended shortly after the beginning of the Ordovician.

Paleontology Nearly 50 fossil genera were found in the Jiangshanian deposits of the Sandu Formation in Guangxi, South China. Organisms presented by the algae, graptolites, the cnidarian Sphenothallus, one species of Palaeoscolecida, and arthropods, which include aglaspidid, mollisoniid, and "bivalved" forms. Rare hurdiids were discovered in the Jiangshanian strata in Sandu Formation and Wiśniówka Sandstone Formation in Poland. Trilobites Parabolina, Hedinaspis, Eugonocare and Cermatops, with agnostoid genera including Pseudagnostus and Rhaptagnostus, were collected from the Jiangshanian sediments of western Tasmania. Trilobite genera Monocheilus, Ptychaspis and Wilbernia are known from the Jiangshanian Honey Creek Formation in the Wichita Mountains, Oklahoma, USA.

References

External links "GSSP of the Jiangshanian Stage in the Duibian B section, Zhejiang, China". timescalefoundation.org. Archived from the original on 2022-05-26. "GSSP Table - Paleozoic Era". Archived from the original on 2023-10-08. "GSSPs - The Cambrian System 2019". International Commission on Stratigraphy. Archived from the original on 2023-07-21.

Worked examples

Example 1 — a first encounter with Jiangshanian

Start with the simplest possible case. Write down what Jiangshanian 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 Jiangshanian 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 Jiangshanian 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 Jiangshanian

In research: Jiangshanian 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 Jiangshanian 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: Jiangshanian is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cambrian geochronology, Geological ages, Jiangshanian, so understanding it makes those chapters shorter.
In everyday life: Look for Jiangshanian 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 Jiangshanian in 20 minutes

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

Frequently asked questions

What is Jiangshanian in simple terms?

The Jiangshanian is the middle stage of the Furongian series. It follows the Paibian Stage and is succeeded by the still unnamed Stage 10 of the Cambrian.

Why does Jiangshanian 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 Jiangshanian?

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 Jiangshanian.