1.
Which characteristic is absolutely necessary for a sedimentary rock to have potential as a possible reservoir rock for oil or gas?
Correct Answer
A. High porosity
Explanation
High porosity is necessary for a sedimentary rock to have potential as a possible reservoir rock for oil or gas because it refers to the amount of empty space or voids within the rock. These empty spaces can act as storage areas for oil or gas, allowing them to accumulate and be extracted. Without high porosity, the rock would not have the capacity to hold significant amounts of oil or gas, making it unsuitable as a reservoir rock.
2.
Coal beds originate in _______.
Correct Answer
D. Freshwater coastal swamps and bogs
Explanation
Coal beds originate in freshwater coastal swamps and bogs. This is because coal is formed from the remains of plants that lived in these environments millions of years ago. Over time, the plant material accumulates and is buried under layers of sediment. The heat and pressure from the overlying layers cause the plant material to undergo chemical changes and eventually turn into coal. Therefore, the correct answer is freshwater coastal swamps and bogs.
3.
Which of the following sedimentary features can each be used to determine paleocurrent directions?
Correct Answer
B. Ripple marks and cross stratification
Explanation
Ripple marks and cross stratification can be used to determine paleocurrent directions. Ripple marks are formed by the movement of water or wind, and their orientation can indicate the direction of the current. Cross stratification refers to the layering of sediment at an angle to the horizontal, which also provides information about the direction of the current. Therefore, by studying these sedimentary features, scientists can determine the direction in which the ancient currents flowed.
4.
Oolitic limestone is most likely to form in what type of depositional environment?
Correct Answer
B. Shallow, clear, marine waters with vigorous current activity
Explanation
Oolitic limestone is most likely to form in shallow, clear, marine waters with vigorous current activity. This is because oolitic limestone is composed of small spherical grains called ooids, which are typically formed through the rolling and cementation of sediment in high-energy environments. Shallow, clear, marine waters with vigorous current activity provide the ideal conditions for the formation and accumulation of these ooids, leading to the formation of oolitic limestone.
5.
____is the most common type of chemical sedimentary rock
Correct Answer
A. Limestone
Explanation
Limestone is the most common type of chemical sedimentary rock because it is formed from the accumulation and lithification of calcite or aragonite, which are minerals made up of calcium carbonate. It is often formed in marine environments through the deposition of shells, coral, and other organic materials. Limestone can also form through chemical precipitation from groundwater. Its widespread occurrence and abundance in various geological settings make it the most common type of chemical sedimentary rock.
6.
Which of the following sedimentary rocks would you expect to have originally been deposited by fast-moving streams?
Correct Answer
D. Conglomerate
Explanation
Conglomerate is the correct answer because it is a type of sedimentary rock that is formed from the accumulation of rounded gravel-sized particles, such as pebbles and cobbles. These particles are typically transported and deposited by fast-moving streams or rivers. Therefore, conglomerate is likely to have originally been deposited by fast-moving streams.
7.
Which of the following is not a type of limestone?
Correct Answer
D. Conglomerate
Explanation
Conglomerate is not a type of limestone. Limestone is a sedimentary rock mainly composed of calcium carbonate, while conglomerate is a sedimentary rock composed of rounded fragments of different sizes and types of rocks that are cemented together. Therefore, conglomerate cannot be classified as a type of limestone.
8.
Which of the following sedimentary features would typically be found in shales but not in sandstones?
Correct Answer
A. Mud cracks
Explanation
Mud cracks are typically found in shales because shales are fine-grained sedimentary rocks that are composed of clay and silt particles. These rocks have a tendency to shrink and crack when they dry out, forming distinct patterns of mud cracks. On the other hand, sandstones are coarser-grained rocks composed of sand particles, which do not have the same tendency to crack and form mud cracks. Therefore, mud cracks are more commonly found in shales rather than in sandstones.
9.
Sedimentary rocks account for about what percentage of the Earth's outermost 10 kilometers of rock (first percentage). Also, what percentage of the Earth's continental area is covered by sedimentary rocks (second percentage)?
Correct Answer
A. 5% & 75%
Explanation
Sedimentary rocks make up only about 5% of the Earth's outermost 10 kilometers of rock. This means that the majority of the Earth's outermost rock is composed of other types of rocks, such as igneous or metamorphic rocks. On the other hand, sedimentary rocks cover approximately 75% of the Earth's continental area. This indicates that sedimentary rocks are more prevalent on the Earth's continents compared to other types of rocks.
10.
Flint, chert, and jasper are microcrystalline forms of ________.
Correct Answer
A. Quartz
Explanation
Flint, chert, and jasper are all types of rocks that are microcrystalline forms of quartz. Quartz is a mineral that is composed of silicon and oxygen, and it is known for its hardness and durability. Flint, chert, and jasper all have a similar microcrystalline structure, which means that they are made up of tiny quartz crystals that are too small to be seen with the naked eye. These rocks are often used for making tools and weapons due to their hardness and ability to hold a sharp edge.
11.
Detrital sedimentary rocks are classified named based on the
Correct Answer
B. Grain sizes of the detriatal particles
Explanation
Detrital sedimentary rocks are formed from the accumulation of sediments that have been weathered and eroded from pre-existing rocks. These sediments are transported and deposited, and over time, they become compacted and lithified to form rocks. The grain sizes of the detrital particles play a significant role in the classification of these rocks. Different grain sizes, such as sand, silt, or clay, indicate different depositional environments and processes. Therefore, classifying detrital sedimentary rocks based on the grain sizes of the detrital particles helps to understand their formation and the conditions under which they were deposited.
12.
_________ is not a common cementing agent for sandstones.
Correct Answer
C. Fluorite
Explanation
Fluorite is not a common cementing agent for sandstones because it is not commonly found in nature as a cementing material. Quartz, calcite, and iron oxides are more commonly found as cementing agents in sandstones. Fluorite is a mineral that is typically found in hydrothermal veins and is not commonly associated with the cementation of sandstones.
13.
What is probably the single most important, original, depositional feature in sedimentary rocks?
Correct Answer
C. Bedding or stratification
Explanation
Bedding or stratification is the most important, original, depositional feature in sedimentary rocks because it represents the layering or arrangement of sediments that were deposited over time. This layering provides valuable information about the environment in which the sediments were deposited, such as the flow of water or wind, and can also indicate changes in sedimentation patterns over time. Bedding or stratification is a key characteristic used by geologists to interpret the history and formation of sedimentary rocks.
14.
Which of the following describes the correct order for relative solubility of minerals in sedimentary rocks?
Correct Answer
C. Evaporate minrals are more soluble than calcite and quartz
Explanation
Evaporate minerals are more soluble than calcite and quartz. This means that when placed in a solvent, evaporate minerals will dissolve more readily than calcite and quartz.
15.
____cement produces bright-red and yellow colors in some sandsone
Correct Answer
D. Iron oxide
Explanation
Iron oxide is the correct answer because it is known to produce bright-red and yellow colors in some sandstone. Iron oxide is a common mineral that contains iron and oxygen, and it can occur naturally in sandstone formations. When iron oxide is present in the sandstone, it imparts vibrant red and yellow hues to the rock. This is why iron oxide is responsible for the colorful appearance of certain sandstone formations. Clay, calcite, and quartz do not typically produce these bright colors in sandstone.
16.
Gravwacke is___
Correct Answer
B. A sandstone with the sand grains embedded in a clay rich matrin
17.
What is the main difference between a conglomerate and a sedimentary breccia?
Correct Answer
A. Breccia clasts are angular; conglomerate clasts are rounded
Explanation
The main difference between a conglomerate and a sedimentary breccia is that the clasts in a breccia are angular, while the clasts in a conglomerate are rounded.
18.
Compaction is a very important part of the lithification process for which of the following sediments?
Correct Answer
C. Mud
Explanation
Compaction is a crucial step in the lithification process for mud sediments. Mud consists of fine particles that are easily compressed under pressure, leading to the removal of water and air between the particles. This compaction process helps in the formation of sedimentary rocks, such as shale, by reducing the porosity and increasing the density of the mud sediment.
19.
___________, a common mineral found in igneous rocks, is the most abundant mineral in detrital sedimentary rocks.
Correct Answer
C. Quartz
Explanation
Quartz is the most abundant mineral in detrital sedimentary rocks because it is a common mineral found in igneous rocks. When igneous rocks weather and erode, the quartz grains are transported and deposited in sedimentary rocks. This process of weathering and erosion breaks down the rocks into smaller particles, and quartz is resistant to weathering, making it more likely to survive and be deposited in sedimentary rocks. As a result, quartz becomes the most abundant mineral in detrital sedimentary rocks.
20.
____sandsone contains abundant feldspar suggesting that the sand was derived by wathering and erosion of granitic bedrock
Correct Answer
C. Arkosic
Explanation
The correct answer is "arkosic." Arkosic sands contain abundant feldspar, which suggests that the sand was derived from the weathering and erosion of granitic bedrock. This is because feldspar is a common mineral found in granitic rocks. Therefore, the presence of abundant feldspar in the sand indicates that it likely originated from the breakdown of granitic bedrock through weathering and erosion processes.
21.
Which of the following best describes bedded gypsm and halite?
Correct Answer
D. Evaporates; chemical, sedimentary rocks
Explanation
Bedded gypsum and halite are evaporates, which means they are formed by the evaporation of water from a solution. They are chemical sedimentary rocks because they are composed of minerals that precipitate out of solution. Detrital sedimentary rocks are formed from the accumulation of weathered and eroded fragments of other rocks. Dolostone is a type of sedimentary rock composed primarily of the mineral dolomite. Coal and peat are organic sedimentary rocks formed from the accumulation and compaction of plant remains.
22.
Which of the following applies to the basic constituents of halite, gypsum, and sylvite?
Correct Answer
C. Transported as dissolved ions; deposited by evaporation