Question

Seafloor Spreading The distance between two locations across an ocean basin increases by \(1.8 \mathrm{~cm}, 4.1 \mathrm{~cm}\), and \(3.2 \mathrm{~cm}\), each year respectively. What is the average rate of separation of these locations during this time?

Short answer

The average rate of separation is approximately \(3.03\, \text{cm/year}\).

Step-by-step solution

Identify the Distances

The given distances that the seafloor spreads are \(1.8\, \text{cm}\), \(4.1\, \text{cm}\), and \(3.2\, \text{cm}\) each year, respectively.

Determine the Number of Years

The distances are provided for three consecutive years. Thus, the number of years is 3.

Calculate the Total Distance

Sum up the distances over the three years: \(1.8 + 4.1 + 3.2 = 9.1\, \text{cm}\). This is the total distance by which the locations have separated in three years.

Calculate the Average Rate of Separation

To find the average rate of separation, divide the total distance by the number of years: \[\text{Average Rate} = \frac{9.1 \text{ cm}}{3 \text{ years}}\].

Solve the Equation

Perform the division: \(\frac{9.1}{3} = 3.0333\, \text{cm/year}\). Round to two decimal places for an approximate rate of \(3.03\, \text{cm/year}\).

Key concepts

Ocean Basins

Ocean basins are vast, deep underwater surfaces that hold the great bodies of saltwater constituents, commonly known as oceans. These basins are shaped by the dynamic and ever-changing processes of plate tectonics, which cause changes to them over geological time frames.
Ocean basins are mainly created by the activity of seafloor spreading, a fascinating process where tectonic plates—the enormous slabs of the Earth's crust—drift apart as magma oozes up to create new oceanic crust. This occurs mostly along mid-ocean ridges, which are submarine mountain ranges formed by plate tectonics.

• *Variety of Features*: Ocean basins include various features such as abyssal plains, trenches, and ridges, each adding complexity to these vast underwater landscapes.
• *Critical for Marine Life*: They provide a habitat for a wide range of marine organisms, hosting unique ecosystems.
• *Geological Indicators*: Changes and formations within ocean basins can tell us a lot about Earth's history, including past climate and geological events.

Understanding ocean basins helps us appreciate the interconnected nature of Earth's systems and the continuous creation and recycling of the ocean floor.

Average Rate of Separation

The average rate of separation refers to the speed at which two locations move away from each other over time. This concept is particularly important in the context of seafloor spreading, providing insights into how quickly tectonic plates are drifting apart.
Calculating the average rate of separation involves finding the total distance that the ocean floor has widened over a set period and dividing it by the number of years it took for this distance to increase.

• *Given Data*: For example, imagine an ocean basin where the separation distances are given as 1.8 cm, 4.1 cm, and 3.2 cm for consecutive years.
• *Total Distance*: Calculating the total distance involves summing up these numbers, yielding 9.1 cm.
• *Time Period*: This occurs over 3 years, meaning an average calculation is needed.
• *Calculation*: Thus, the average rate of separation is 9.1 cm divided by 3 years, resulting in approximately 3.03 cm/year.

This average rate signifies how quickly the tectonic plates are moving, which can impact geological formations and even influence seismic activities across the globe.

Plate Tectonics

The theory of plate tectonics is a comprehensive scientific explanation for the movement of Earth's outer shell, consisting of large tectonic plates. This serves as the fundamental model describing the geology of our planet and shapes its topography and geological phenomena.
Tectonic plates move atop the relatively fluid asthenosphere beneath the Earth's lithosphere. Their interactions are responsible for creating many major geological features and are vital in explaining the phenomenon of seafloor spreading.

• *Types of Plate Boundaries*: There are divergent boundaries where plates move apart, convergent boundaries where they collide, and transform boundaries where they slide past each other.
• *Seafloor Spreading*: Specifically occurring at divergent boundaries, this process occurs at mid-ocean ridges and is fundamental in forming new oceanic crust.
• *Global Impact*: Movements cause earthquakes, volcanic activity, and the creation of mountain ranges.

Understanding plate tectonics allows us to ground important geological processes in a framework, making sense of natural occurrences and the continuous evolution of our planet's surface.