Question

Studies have shown that during the Ice Age, the margins of some ice sheets advanced southward from the Hudson Bay region at rates ranging from about 50 to 320 meters per year. a. Determine the maximum amount of time required for an ice sheet to move from the southern end of Hudson Bay to the south shore of present day Lake Erie, a distance of 1600 kilometers. b. Calculate the minimum number of years required for an ice sheet to move this distance.

Short answer

a) 32,000 years; b) 5,000 years.

Step-by-step solution

Convert Distance to Meters

To calculate the time required, we first need to convert the distance from kilometers to meters. We know that 1 kilometer is equivalent to 1,000 meters. Therefore, the distance of 1600 kilometers can be expressed in meters as follows: \[ 1600 \text{ kilometers} \times 1000 = 1,600,000 \text{ meters} \]

Calculate Maximum Time Using Minimum Speed

The maximum time is calculated using the slowest speed at which the ice sheet moves. Given the slowest speed is 50 meters per year, we can determine the maximum time as follows:\[ \text{Maximum Time} = \frac{1,600,000 \text{ meters}}{50 \text{ meters/year}} = 32,000 \text{ years} \]

Calculate Minimum Time Using Maximum Speed

The minimum time is calculated using the fastest speed at which the ice sheet moves. Given the fastest speed is 320 meters per year, we can determine the minimum time as follows:\[ \text{Minimum Time} = \frac{1,600,000 \text{ meters}}{320 \text{ meters/year}} = 5,000 \text{ years} \]

Key concepts

Ice Age

The Ice Age refers to a period in Earth's history when large portions of the planet's surface were covered by glaciers. These massive ice sheets extended from the polar regions toward the equator, reshaping landscapes and influencing climates. This period is characterized by colder global temperatures and is divided into several glacial and interglacial cycles. Understanding the Ice Age helps scientists learn about past climate changes and predict future environmental shifts. It lasted tens of thousands of years, with some cycles occurring as recently as 12,000 years ago. The expansion and contraction of glaciers during the Ice Age had profound impacts on Earth's ecosystems, creating new landforms and driving the migration of species.

Ice Sheets

Ice sheets are enormous expanses of ice that cover continental areas. They can be over several kilometers thick and span thousands of kilometers. The two most significant ice sheets today are found in Antarctica and Greenland. During the Ice Age, these ice sheets extended beyond their current boundaries. For example, massive ice sheets expanded southward from the Hudson Bay region in Canada into the United States. Ice sheets move or "flow" due to gravity and pressure from their accumulated mass. Their movement can reshape mountains and carve out valleys, an activity crucial for understanding historical climate patterns. Throughout history, ice sheets have also played a vital role in Earth's water cycle by storing large amounts of freshwater.

Hudson Bay Region

The Hudson Bay region is located in northeastern Canada and was a focal point for glacial activity during the Ice Age. It acts as a massive basin collecting water from rivers and melting ice. During the last glacial period, ice sheets from this area advanced significantly, affecting surrounding regions' geography. These glacial advancements were primarily responsible for reshaping landscapes, including the formation of lakes and changes in river paths. Nowadays, Hudson Bay is known for its rich ecosystems and serves as an essential waterway for marine life. Its geological history provides valuable insights into glacial movement and climate change, which helps scientists understand past and potential future environmental and geographical transformations.

Lake Erie

Lake Erie is one of the five Great Lakes of North America and played an essential role during and after the Ice Age. It formed as a result of the glacial movements that carved basins, now filled with water. The retreat of glaciers from the Hudson Bay region toward Lake Erie reshaped the area and contributed to its current land and water formations. This lake is the shallowest of the Great Lakes, making it the warmest, which affects its ecological dynamics and the weather patterns of surrounding regions. The proximity to large ice sheets during the Ice Age means that evidence of historical glacial activity is still visible today. Lake Erie's formation and history provide crucial information for geologists studying glacial impact and freshwater systems.