Organic Matter in Fluvial Systems

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What is the primary factor that determines whether a kerogen will be oil-prone or gas-prone?

The amount of FIGURE 2.7 incorporated into the sediments
The preservation conditions of the organic matter
The hydrogen content and structural makeup of the kerogen (correct)
The type of organisms that contributed organic matter

What type of organic matter is rich in hydrogen?

Starch and sugars
Nucleic acids and cellulose
Hydrocarbons, waxes, fats, and lipids (correct)
Proteins and carbohydrates

What is the outcome when kerogen is unable to generate oil or gas?

It becomes gas-prone
It becomes oil-prone
It disappears completely
It becomes inert kerogen (correct)

What determines the type of hydrocarbon generated from a kerogen?

The type of organic matter incorporated into the sediment (C) Signup and view all the answers

What is necessary for a kerogen to be oil-prone?

High hydrogen content and complex structures (D) Signup and view all the answers

What is the difference between oil-prone and gas-prone kerogen?

Oil-prone has high hydrogen content, while gas-prone has low hydrogen content (C) Signup and view all the answers

What sedimentation rate is conducive for source rock development?

1 mm/year (D) Signup and view all the answers

What is the primary process that breaks down organic matter in sediments?

Microbial activity and oxidation (A) Signup and view all the answers

What is the result of the transformation of biological organic matter in sediments?

Formation of kerogen (A) Signup and view all the answers

What is the main difference between fine-grained and coarse-grained sediments?

Preservation of organic matter (C) Signup and view all the answers

What is the purpose of studying source rock occurrences?

To determine the conditions for source rock development (B) Signup and view all the answers

What is the role of microbial activity in kerogen formation?

To break down large molecules (C) Signup and view all the answers

What is the primary source of organic matter in fluvial systems?

Terrestrial higher plants (D) Signup and view all the answers

What is required for sufficient amounts of organic matter to contribute to sediments and form a source rock?

High primary biological productivity (B) Signup and view all the answers

What controls primary biological productivity?

Nutrient supply and solar radiance (B) Signup and view all the answers

What is the fate of reworked organic matter in terms of oil and gas conversion?

It has low capacity for conversion (D) Signup and view all the answers

What is the role of eolian processes in delivering organic matter to depositional environments?

Minor mechanism for delivering organic matter (C) Signup and view all the answers

What is the significance of autochthonous and allochthonous contributions in source rock development?

They are important in source rock development (B) Signup and view all the answers

What is the primary source of hydrogen-rich organic matter in sediments?

Algae, bacteria, leaf cuticle, spores, and pollen (A) Signup and view all the answers

Under what conditions is the hydrogen content of organic matter preserved in sediments?

Anoxic conditions (C) Signup and view all the answers

What happens to hydrogen-rich organic matter when it is poorly preserved under oxic conditions?

It becomes inert kerogen (A) Signup and view all the answers

What is the result of poor preservation of hydrogen-poor organic matter under oxic conditions?

It loses its gas-generating capacity (B) Signup and view all the answers

How are oil-prone kerogens further classified?

Into waxy oil-prone and naphthenic oil-prone kerogens (B) Signup and view all the answers

What is the primary classification of kerogens based on?

Their chemical properties and potential (B) Signup and view all the answers

What is one mechanism for rapidly transporting autochthonous organic matter to the seafloor?

By fecal pellets from zooplankton (C) Signup and view all the answers

Why is the zooplankton not a very efficient digester of phytoplankton?

Because much of the organic matter is conserved (A) Signup and view all the answers

What is a key factor in the preservation of organic matter at the sediment-water interface?

The amount of oxygen available (B) Signup and view all the answers

What happens to organic matter at the sediment surface if the oxic/anoxic boundary is substantially below the sediment-water interface?

It is consumed by aerobic organisms (A) Signup and view all the answers

What is 'marine snow'?

A component of fecal pellets (C) Signup and view all the answers

What is an example of an inorganic chemical process that can degrade organic matter?

Oxidation (B) Signup and view all the answers