Golden Spike Activity Set:
Introduction
Now that we know how epochs are named and understand that Scientists have not yet universally agreed upon a golden spike to mark the beginning of the Anthropocene on the geological time scale. We are ready to explore if there should indeed be a Golden Spike placed at the top of the Geologic Timescale chart- above the Holocene, to mark this latest chapter in the Earth’s history.
As we have heard, some scientists believe it is too soon to decide on a marker and advocate doing more research on the matter. Other scientists believe the Anthropocene ought to have begun thousands of years ago, when humans could be found on all major continents. Still others argue that humans have had a measurable impact on the natural systems of the Earth only since industrial times and call this the Great Acceleration.
Watch Video: When did the ‘age of humans’ begin?Links to an external site.
The use of the term “Anthropocene”, which has yet to be formally adopted into the official geologic time scale, is supported by an international collective of scientists who believe that the Holocene, our current geological epoch, characterized by stable climates and minimal human impacts, has indeed ended.
Instead, they suggest this new epoch, the Anthropocene, in its place due to unprecedented human land use, resource consumption and waste production.
We will look at the proposed naming of this time we are in as the Anthropocene – which as mentioned is currently only a scientific proposal. We will also explore why it has become so broadly influential yet not fully accepted. Then you can decide for yourself, is it still the Holocene, is it the Anthropocene? Is it…_____________?
In summary, as you have learned: Historically, the term “golden spike” referred to the ceremonial 17.6-karat gold final spike driven into the ground to connect the Central Pacific and Union Pacific railroads that together formed the First Transcontinental Railroad across the United States in 1869.
In the Earth sciences, the term “golden spike” is used to describe a geological marker or a boundary in the sedimentary rock or fossil record that shows where one period of time ends and another clearly begins.
A committee of experts who work for the International Commission on Stratigraphy decides which time periods get formally adopted into the geological time scale. Stratigraphy is the study of the order and positioning of different layers in the Earth’s crust.
A golden spike is chosen because it can be measured in the sedimentary or fossil record using samples from
different places around the world.
Examples of already universally accepted golden spikes that can be found on the geologic timescale include the following:
Treptichnus pedum: the fossilized burrow of long-extinct animal
The fossilized burrows of the Treptichnus animal first appeared in sedimentary rock layers around the
world between the Precambrian (the earliest part of Earth’s history) and the Cambrian (the period that
came afterwards). This is an example of a golden spike that is a fossil.
Extraordinary amounts of iridium in soils around the world
Sixty-six million years ago, a meteorite from space collided with the Earth causing a dust storm that blocked out the sun and caused the global climate to change, resulting in the extinction of many animals, including the dinosaurs, and a rapid increase in the amount of the metal iridium in the soil of the Earth. This is an example of a golden spike that is a metal.
Gas bubbles marking an abrupt shift in the climate on Earth
About 11,000 years ago, the Earth started to transition out of an ice age to the current warmer climate.
This transition was marked by change in hydrogen levels in the atmosphere as measured from ancient
gas bubbles trapped in ice cores collected in Greenland. This is an example of a golden spike that is a gas.
Activity
Look at the file: Proposed Anthropocene Marker cards (PDF)Download Proposed Anthropocene Marker cards (PDF)
These images represent some of the most-often discussed proposed golden spike markers for the beginning of the Anthropocene.
Look at each image one at a time- think about what human impact it represents.
The backside of each card ( following page of the PDF) will explain further.
Example: The first card is a woolly mammoth- the next page explains that it represents the extinction of about half of the world’s large-bodied mammals due, in part, to overhunting by humans.
After you look through all the images select one as your vote for the Human Activity Marker or Golden Spike for the Anthropocene Epoch (from a geological and archaeological perspective). What start date would you propose, what type of sedimentological or physical evidence would be used and where the samples would be collected around the world? In essence, pretend you are the voting committee of the International Commission on
Stratigraphy deciding on whether or not to formally adopt the Anthropocene as part of the geological time scale.
Explain your reasoning using your own feelings on human activity so far and of course, the criteria (remember, to earn a golden spike it has to be a global phenomenon)
“to define a specific event or ‘golden spike’ on the geological time scale requires the use of a physical
signal that occurs globally and will persist indefinitely in the fossil record. For example, the extinction of the dinosaurs was marked by a sudden increase in the metal iridium in soils around the world at the time of a collision between a meteorite and Earth.”
As always, be sure your response uses concise, formal language, proper spelling and formatting.