Lithostratigraphic Nomenclature

Question 1

When was the Int’l Subcommission on Stratigraphic Terminology Report on the Principles of Stratigraphic Classification and Terminlogy made?

Answer 1

1961

Question 2

When was the GSP Philippine Code of Stratigraphic Nomenclature made?

Answer 2

1968

Question 3

When was the International Stratigraphic Guide made?

Answer 3

1976

Question 4

When was the 2nd edition of Int’l Stratigraphic Guide made?

Answer 4

1994

Question 5

When was the GSP Committee on Stratigraphic Nomenclature made?

Answer 5

1997

Question 6

When was the Publication of Philippine Stratigraphic Guide made?

Answer 6

2001

Question 7

Basic units of geologic mapping and essential element of the stratigraphy of an area. It is not defined by inferred age, time span they represent and manner of formation.

Answer 7

Lithostratigraphic units

Question 8

Should possess a certain degree of internal lithologic homogeneity or distinctive lithologic features. It may consist of 1)one lithologic typel 2) repetitions of two or more lithologic types. Lithologic heterogeneity, in itself, may constitute a form of unity when compared to the adjacent rock units. In addition it should be mappable at a scale of 1:25,000.

Answer 8

Formation

Question 9

Include chemical and mineralogical composition, texture, and such supplementary features as color, primary sedimentary structures or volcanic depositional structures, fossils (viewed as rock-forming particles), or other organic content (coal, oil-shale)

Answer 9

Lithologic characteristics of Formation

Question 10

Not a determining parameter; may range from less than a meter to thousands of meters as long as it is mappable.

Answer 10

Thickness of Formation

Question 11

Organic reefs and carbonate mounds may be distinguished formally as formations and distinct from their surrounding thinner, temporal equivalents.

Answer 11

Organic reefs and carbonate mounds of formation

Question 12

Sedimentary and volcanic rocks that are interbedded may be assembled into a formation under one name, which should indicate the predominant or distinguishing lithology

Answer 12

Interbedded volcanic and sedimentary rocks formation

Question 13

Mappable, distinguishable sequences of stratified volcanic rocks should be treated as lithostratigraphic units, as formations or as units of higher or lower rank. A small intrusive component of a dominantly stratiform volcanic assemblage may be treated informally, e.g. dikes, sills.

Answer 13

Volcanic rocks of formation

Question 14

Distinguished mainly by lithologic characteristics.

Answer 14

Metamorphic rocks of formation

Question 15

It is a named entity within a formation having characteristics that distinguish it from other parts of a formation. It may not be mappable at the scale required for formations.

Answer 15

Member

Question 16

A geographically restricted unit that terminates on all sides laterally within a formation may be called a ______. A wedging unit may be called a _________.

Answer 16

Lens and tongue

Question 17

Although members are normally in vertical sequence, laterally equivalent parts of a formation that differ recognizably may also be considered members.

Answer 17

Laterally equivalent members

Question 18

May be divided into beds or (volcanic) flows

Answer 18

Division of members

Question 19

The smallest formal lithostratigraphic unit of sedimentary rocks should be limited to certain distinctive _________ whose recognition is particularly useful. Coal, oil sands, and other of economic importance commonly are named.

Answer 19

Bed

Question 20

the smallest formal lithostratigraphic unit of volcanic rocks. The designation should be limited to those that are distinctive and widespread.

Answer 20

Flow

Question 21

Defined to express the natural relationships of associated formations. They are useful in regional mapping and stratigraphic analysis

Answer 21

Group

Question 22

Example of a Flow

Answer 22

Taal Caldera, designating the flow units as Alitagtag Pumice Flow, Caloocan Pumice Flow, Sambong Ignimbrite and Taal Scoria Flow.

Question 23

Example of a Group

Answer 23

Caraballo Group in northeastern Sierra Madre of Luzon, consisting of volcano-sedimentary formations designated as Formations I, II and III

Question 24

T or F. Raising the rank of the unit is preferable to restricting the old name to a part of its former content, because a change in rank leaves the sense of a well-established unit unchanged.

Answer 24

T

Question 25

T or F. The initial letters of all words used in forming the names of formal rock-stratigraphic units are capitalized.

Answer 25

T

Question 26

Compound terms (e.g. carbonaceous shale) and terms that are not in common usage (calcirudite,) should be avoided. Combined terms, such as “sand and clay” should not be used for the lithologic part of the names .

Answer 26

Please read

Question 27

Should indicate the predominant or diagnostic lithology, even if subordinate lithologies are included. The simplest generally acceptable term is recommended (e.g. limestone, sandstone);

Answer 27

Please read

Question 28

T or F. Members designated solely by lithologic character (e.g. limestone member), by position (upper, lower) or by letter or number are informal.

Answer 28

T

Question 29

When geographic names are applied to such as oil sands, coal beds, mineralized zones, and informal members, the unit term should not be capitalized.

Answer 29

Informal units

Question 30

The name of beds or flows may combine a geographic term, lithologic term (optional) and the term “Bed” or “Flow”

Answer 30

Please read

Question 31

Geographic names should be derived from permanent natural or artificial features at or near the place where the stratigraphic unit is present. Names derived from such impermanent sources as farms, churches, schools, crossroads, and small communities are not entirely satisfactory but are acceptable if no others are available.

Answer 31

Please read

Question 32

The original or subsequently designated type section of a named layered stratigraphic unit or of a stratigraphic boundary representing a specific interval or point in a specific sequence of rock strata, and constituting the standard for the definition and characterization of the stratigraphic unit or boundary.

Answer 32

Stratotype

Question 33

The original stratotype designated by the original author

Answer 33

Holostratotype

Question 34

A supplementary stratotype used in the original definition to illustrate the heterogeneity of the stratigraphic unit

Answer 34

Parastratotype

Question 35

A stratotype for a previously described stratigraphic unit selected later in the absence of an adequately designated original stratotype.

Answer 35

Lectostratotype

Question 36

A new stratotype selected to replace the older one which has been destroyed, covered, or otherwise made inaccessible

Answer 36

Neostratotype

Question 37

A stratotype proposed after the original designation of the holostratotype (and parastratotype) in order to extend knowledge of the unit or boundary to other geographic areas.

Answer 37

Hypostratotype

Question 38

A description of the locality and map should enable anyone to find the stratotype. Photos would also help.

Answer 38

Geographic

Question 39

Lithology, thickness, structure, distribution, texture and composition, paleontology, geomorphic expression, and other geologic features of the type section.

Answer 39

Geologic

Question 40

T or F. Adjectives used as nouns, such as “volcanics,” “metamorphics,” “intrusives,” and “extrusives,” preferably should not be used in naming igneous and metamorphic rock bodies. However, they may be reluctantly accepted in formal lithostratigraphic nomenclature when judged useful.

Answer 40

T

Question 41

May be used to describe a diverse assemblage produced by volcanic activity to include extrusive volcanic rocks, related intrusions and associated pyroclastic deposits.

Answer 41

Volcanic complex

Question 42

The term “_______” has been commonly used for associations of apparently co-magmatic intrusive igneous rock bodies of similar or related rock lithologies and close association in time, space, and origin.

Answer 42

suite

Question 43

Assemblages of rock bodies with distinct lithologic characteristics and genetic associations. In a sense, they are a special class of complexes. A complete sequence consists of the following, from the bottom to the top: amphibolite, residual peridotite (harzburgite), transition zone dunite, layered ultramafic cumulates, layered gabbro, isotopic high level gabbro, sheeted dikes/sills complex, pillow basalt and pelagic sedimentary rocks.

Answer 43

Ophiolite sequences

Question 44

In case the assemblage does not represent a complete ophiolite sequence, the composite body may be called an __________.

Answer 44

ophiolitic complex

Question 45

Defined as a body of mappable rock unit (1:50,000) characterized both by the lack of internal continuity of contacts or strata and by the inclusion of fragments and blocks of all sizes, both exotic and native, in a matrix of finer-grained material.

Answer 45

Melange

Question 46

Also known as “sedimentary melange”, consists of a chaotic mass of rock with large clasts older than the enclosing sedimentary sequence.

Answer 46

Olistostromes

Question 47

Gigantic versions of olistostromes are called ________.

Answer 47

olistoliths

Question 48

Example of olistoliths in the Philippines

Answer 48

Codon Formation in Catanduanes with olistoliths of Bonagbonag Limestone.