What does lithofacies mean?
1. n. [Geology] A mappable subdivision of a stratigraphic unit that can be distinguished by its facies or lithology—the texture, mineralogy, grain size, and the depositional environment that produced it.
What is the difference between a facies and lithofacies?
Generally, geologists distinguish facies by the aspect of the rock or sediment being studied. Facies based on petrological characters (such as grain size and mineralogy) are called lithofacies, whereas facies based on fossil content are called biofacies.
What is lithofacies map?
One of the most important tools for reconstructing ancient environments is a lithofacies map a map showing the distribution of rock types (lithofacies) in an area. If the rocks are the same age, this map records the relative positions of various environmental settings at that time in the past.
What is the study of lithology?
Definition of lithology 1 : the study of rocks. 2 : the character of a rock formation also : a rock formation having a particular set of characteristics.
What is Walther’s principle?
Walther’s Law states that any vertical progression of facies is the result of a succession of depositional environments that are laterally juxtaposed to each other.
What does an isopach map show?
Isopach maps display the stratigraphic thickness between an upper and lower horizon. It is measured as the shortest distance between the two surfaces. Isopach maps provide a more accurate picture of stratigraphic thickness, because it reflects the thickness of the deposited bed.
What is a Biofacies in geology?
Definition of biofacies geology. : a part of a stratigraphic unit in which the fossil fauna or flora differs significantly from that found elsewhere in the same unit.
What is difference between lithology and geology?
The main difference between lithology and geology is that lithology describes the properties of a unit of rock, whereas geology describes the occurrence and changing of rock on Earth’s crust over a long time period.
How do you identify lithology?
Neutron and density logs each react to both lithology and porosity, so by analyzing the two logs together, one can begin to distinguish lithology from porosity. Neutron and density logs, together with a caliper measurement recorded by the density tool and a natural gamma ray log, are commonly run as a combination.
What does a lithofacies map display?
What is the importance of Walther’s law in sequence stratigraphy?
Walther’s Law. This allows us to convert a vertical straigraphic section into a reconstructed map of original depositional environments, very powerful concept. It’s important to understand where we can or cannot apply Walther’s Law, or else we may apply it incorrectly and arrive at an unsupportable intepretation.
What is lithology The study of?
What is the meaning of Chronostratigraphy?
Chronostratigraphy is the branch of stratigraphy that studies the ages of rock strata in relation to time. The ultimate aim of chronostratigraphy is to arrange the sequence of deposition and the time of deposition of all rocks within a geological region, and eventually, the entire geologic record of the Earth.
How do you determine lithology?
Lithology is also determined from the logs, because each main reservoir lithology has characteristic responses. Frequently, lithologies are derived by pattern recognition of the GR-, density-, and neutron-log responses. Some subsequent delineation wells are likely to be cored over the entire of the reservoir interval.