Lithosphere I and II Flashcards
What is soil?
It is weathered parent material (e.g. rock) that is capable of supporting life.
Describe the major components of soil and their percentages.
The soil is 50% solid and 50% pores. The pore space breaks down to 25% air and 25% water (total 50%). The solid space breaks down into 45% mineral particles and 5% OM (total 50%).
Describe the breakdown of organic matter in soil.
It breaks down to 80% dead organic material, 10% roots, and 10% organisms
What are mineral particles in soil comprised of?
Sand, silt, and clay.
What is the difference between primary and secondary minerals in soil.
Secondary minerals are primary minerals that have been broken down and decomposed.
What are the 4 major geological event that shaped Quebec?
- The formation of the Grenville province
- The formation of the St. Lawrence platform
- Magma instrusions
- Glaciation
The formation of the Grenville province occurred in the […] era. Explain what the Earth looked like at the time.
Pre-cambrian. At the time, present-day North America, then called Laurentia, was located near the equator.
Explain how the Grenville province was formed.
Laurentia (ancient North America) collided with the Grenville belt, another continental shelf. The heat and pressure formed a very large mountain range called the Grenville mountains.
The Grenville mountains later became […]
The Laurentians that we know today.
The Grenville mountains are […] rocks that are high in […] content.
Metamorphic, rare mineral
The Laurentian mountain range was formed by […]
Erosion
Explain how the formation of the St. Lawrence platform
A rift formed in the Grenville mountain range. This caused the Grenville range and Laurentia to split apart, creating the Lapetus ocean. In the Lapetus ocean, marine sediment accumulated along the shore of the Grenville continental shelf. The marine sediments formed limestone beds, which turned into calcium rocks, which became the bedrock of the St. Lawrence platform.
The St. Lawrence platform left […] behind. This occurred through the process of […]
Sedimentary rocks, erosion of limestone beds
What is Montreal greystone?
It is greystone that comes from limestone from the St. Lawrence linestone beds.
How long ago did the formation of the Grenville province occur?
Around 1 billion years ago
How long ago did the formation of the St. Lawrence platform occur?
Around 1 billion years ago
How long ago did magma intrusions occur?
125 million years ago
How long ago did glaciation occur?
35000-10000
The recent geological features are formed from […] and […] events.
Depositional and erosion
Is erosion a destructive or a creative force?
It is both. It is destructive in that it moves materials to other areas, but it creates new forms with those materials and exposes the materials underneath the original materials.
Is deposition a destructive or a creative force?
It is a creative force. It depots materials from geologic event.
Deposition and erosion lay the foundation of the […] of soil.
Parent material
What is parent material?
It is the unconsolidated mineral or organic material from which the true soil develops.
Describe the third geologic event: igneous intrusions
Magma rose from below the Earth’s crust. These underground magma chambers eventually cooled, forming igneous rock. The result was igneous intrusions below the limestone St. Lawrence platform. Since limestone is easily weathered and igneous rock is highly resistant, the igneous intrusions underneath were gradually exposed.
What did igneous intrusions leave behind?
The Monteregian Hills, which include Mount Royal, Mont St. Hilaire, Rougement, etc. They are uneroded igneous intrusions where sedimentary rock (limestone) was eroded away.
Explain the fourth geologic event. Include its 3 major consequences.
The fourth event was glaciation. Glaciers 2-3 km thick formed, which depressed the crust of the Earth . They:
1. Wore away and levelled the Grenvillian and Monteregian mountains
2. Left behind a trail of stones and rocks and glacial till
3. Created seas (Champlain sea) and deposited clays.
Describe the effect that glaciation has on the landscape.
Glaciers picked up rocks, stones, and eroded the landscape as they moved. Then, when the glaciers melt or retreat, this rock is left behind.
Glacial activity left behind […]
Glacial till in much of the St. Lawrence lowland, the Hudson bay and northern lowlands and peatlands, and the deposition of Leda clays.
What is glacial till?
It is accumulations of unsorted, unstratified mixtures of clay, silt, sand, gravel, and boulders.
Explain how glacial activity left behind the Hudson bay and northern lowlands and peatlands.
During peak glaciation, the weight of the glacier caused the Earth’s crust to sink and the mantle to be pushed outward and up. During deglaciation, the crust remains depressed and ocean water and glacial melt filled it. The crust then slowly comes back up, but it is still rebounding - these are the lowlands.