Principles of Geology of Venezuela Class Notes - Partial Exam I PDF

# Principles of Geology of Venezuela ## Class Notes for Partial Exam I **Topics:** * The stratigraphic column. * The determination of time in Geology (absolute age and relative age). * Discordance or discontinuities. Time involved in discontinuities. * Stratigraphic units: lithostratigraphy, bios...

# Principles of Geology of Venezuela ## Class Notes for Partial Exam I **Topics:** * The stratigraphic column. * The determination of time in Geology (absolute age and relative age). * Discordance or discontinuities. Time involved in discontinuities. * Stratigraphic units: lithostratigraphy, biostratigraphy, chronostratigraphy. * Facies in stratigraphy. * Paleogeographic reconstruction. * The determination of paleoenvironments (main sedimentary environments). * Physiography of Venezuela. ## Fundamental Principles of Stratigraphy: 1. **Principle of Original Horizontality (Nicolás Steno 1666-1669):** Sediments are originally deposited in a horizontal position unless there is a force that deforms them. 2. **Principle of Superposition of Strata (Nicolás Steno 1666-1669):** In an undeformed sequence of sedimentary rocks, the oldest strata are found at the base, and the most recent strata are found at the top. 3. **Principle of Lateral Continuity (Nicolás Steno 1666-1669):** Layers extend laterally until they are interrupted by a geological accident. 4. **Principle of Uniformitarianism (Actualism) James Hutton 1785 (developed by Charles Lyell 1830-1833):** Geological processes that occurred in the past are similar to those we observe today. Hutton "the present is the key to the past". 5. **Principle of Faunal Succession William Smith (1815):** States that fossils appear in a specific order in the geological record, which is irreversible in time, allowing the correlation of strata in different locations. 6. **Principle of Cross-Cutting Relationships, Nicolás Steno (expanded by Charles Lyell 1830-1833):** Any geological structure that cuts another is younger than the rock it cuts. 7. **Principle of Inclusion Nicolás Steno:** A rock fragment included within another rock is older than the rock that contains it. ## The Stratigraphic Column or Stratigraphic Succession The stratigraphic column is the graphic representation of the set of rocks that are described, and it is done respecting the fundamental principle of succession. The **STRATIGRAPHIC COLUMN IS THE FUNDAMENTAL BASIS FOR ANY GEOLOGICAL STUDY**, as it serves to make interpretations of the environments of sedimentation of the past, when we have more than one column, correlations can be made in an area under study, thus determining the continuity of the strata (e.g., lateral continuity). It is important to highlight the scale of work in the legend, the individual thicknesses of the layers, the total thickness, the description of each stratum, field observations, sample collection, and provide a legend. To present it formally, the stratigraphic unit to which it belongs should be included unless the work is still in progress (informal units). This formality refers to the data of the lithostratigraphic and chronostratigraphic units: Group, Formation, Member, etc., Age (period, floor, etc.). To create a column, it is necessary to look for field data in outcrops (natural ravines or road cuts) or to describe cores of the subsoil. It is necessary to verify that the strata are in their normal position using sedimentary structures that indicate the base or the top. The following aspects are described within the strata: * Lithology(ies): grain size, fresh and weathered color, sedimentary structure (indicative of processes), paleontological content, degree of bioturbation, mineralization, compaction or fissility, contacts between layers if there are fractures, etc. We can find stratigraphic columns integrated with paleontological studies (foraminifera, calcareous nanoplankton, graptolites, conodonts, molluscs, echinoderms, etc.) or integrated with data from the subsoil with well logs (sp, gr and electrical profiles), paleoenvironmental interpretations can also be included, and grain size patterns can be placed depending on the study. <start_of_image> Schematic model for a basic stratigraphic column. | Age | Units | Thickness | Lithology | Grain Size | Sedimentary Structures | Bioturbation | Samples | Observations | |---|---|---|---|---|---|---|---|---| | - | - | - | - | - | - | - | - | - | | | | | | | | | | | Each column should have its legend and graphic scale. ## Determining Time in Geology Time in geology is recognized in two ways: one is relative time, which refers to events that have occurred before or after, without specifying time (e.g., faunal succession); while absolute age is expressed in time units (years or multiples thereof). For determining the **absolute age**, the following methods are used: 1. **Dendrometry or Dendrochronology:** a method of dating that is based on the study of the growth rings of trees. Each ring represents one year of growth, allowing to establish precise chronologies. It also provides information on the climate and the environment, for example, droughts or rainy seasons, when the ring grows a little bit more. In ecology, it helps to understand the forest dynamics of the area. 2. **Varves:** a method of absolute dating based on the study of samples of sediments from the bottom of glacial lakes. The samples or alternating sediments called lacustrine varves, which are found in the bottoms of lakes, are counted by years of formation, each pair of light and dark layers represent the annual seasonal period. Light layers are expected during the spring–summer period (silts and fine sands) and dark layers in winter seasons when the lake is frozen, where sediments can be rich in organic matter (clays and organic matter). Thus, with pairs of layers, you can count the years of varve formation and establish chronologies for dating. These patterns or sequences are also used to identify climatic patterns and correlate stratigraphic sequences in different geographic regions where there are lakes. Dating can be very precise and effective for recent periods (up to tens of thousands of years), allowing annual dating, which is superior to methods like carbon-14, which has a temporal limit of approximately 50,000 years. One limitation is that it only applies to glacial lakes and that they can be affected by erosion processes that alter the sequence. 3. **Radiometry**: is a method used in geology to determine the age of rocks. The method consists in the disintegration of an element or radioactive isotopes by a process in which an unstable isotope (known as the parent isotope), transforms into another more stable isotope (called daughter isotope), through a process known as radioactive decay. The decay constant is obtained when the nucleus radioactive disintegrates within a given time interval. The half-life of an isotope is measured by observing the number of nuclei that remain active in a sample over time. This process involves measuring the initial activity of the isotope, observing its decay at regular intervals or half-life, which is the time it takes for the activity to be reduced by half. This process must being repeated to obtain precise data about the time it takes for activity to be reduced by half in multiple cycles, and it is necessary to carry out mathematical calculations to determine the age of rocks or materials. 4. **Utility of radioactive isotopes, type of rocks, and temporal range:** * In igneous and metamorphic rocks, the Uranium-Lead (U-Pb) isotope method is used due to its long half-life and its ability to provide accurate dates over a wide range. It uses the isotopes U²³⁸ to Pb²⁰⁶, U²³⁵ to Pb²⁰⁷, giving a temporal range from millions to 4.5 billion years, using zircon minerals. * In igneous and volcanic rocks, the Potassium-Argon (K-Ar) method is used, using the isotopes ⁴⁰K to ⁴⁰Ar, for a temporal range of 100,000 to several million years. * The Carbon-14 method, although not applied directly to sedimentary rocks but to organic remains, is used to date recent sediments, examples of dunes, and covers up to 50,000 years, being used in archeology, in organic remains. * In intensely metamorphosed very old rocks, igneous rocks, and even in meteorites, the Samarium-Neodymium (Sm-Nd) method is used, using the isotopes ¹⁴⁷Sm to ¹⁴³Nd, for a temporal range from billions to more than 4.5 billion years. 5. **Thermoluminescence**: is a technique of absolute dating used to determine the time elapsed since materials were last heated. Minerals that emit light under UV (quartz, feldspar) can be useful for thermoluminescence induced by heating. It is used to date mainly aeolian sediments, and in some cases alluvial, marine and coastal sediments, even those in caves (stalagmites). In volcanic rocks if they have been affected by recent heating. 6. **Fission Tracks**: Fission track dating is a method that is based on the spontaneous fission of the uranium-238 isotope found in various minerals like apatite, zircon, sphene etc.. In the process with an acid treatment, tiny tracks are revealed in the crystalline structure of the minerals, which can be counted by using an electron microscope The number of tracks observed is proportional to the time elapsed since formation. The equations relating the number of tracks observed to the elapsed time, taking into account the fission rate of Uranium, are used. This relationship allows to calculate the age of the sample, and the time measured can range from thousands to millions of years, depending on the initial Uranium content and the geological conditions. 7. **Time Scale of Geomagnetic Polarity (GPTS)**: This is a record of the beginning and duration of the reversals of Earth's magnetic polarity, reflected in the rocks of the ocean floor over time. In the decade of 1960 after World War II, complex relief was observed in the exploration of the ocean floor. In 1963 to 1966, scientists F.J. Vine and D.H. Matthews, confirmed the magnetism in the rocks. The ocean basalts at oceanic ridges register the Earth's magnetic polarity, as they solidify, which are formed symmetrically on both sides of the mid-ocean ridges. 8. **Magnetostratigraphy:** Thorough studies of rocks from around the world, with patterns of magnetic inversions and those of known age, allowed to establish approximate ages of rocks. The inversions of polarity are useful as a tool for dating, and they are used in conjunction with chronostratigraphy and biostratigraphy. It is a dating technique that covers up to 4 million years, it allows dividing the magnetostratigraphic scale into time intervals, called polarity chrons, which are named from the most modern to the Aptian (C1 to C34), and from the lower Aptian to the Callovian (CMO and CM1 to CM29). Note in the following image a detail of how it is observed in the table of geological time, the integration of data of magnetic polarity chronozones where, by convention: normal polarity is represented in black and reverse in white. * *Cenozoic* | Age | Polarity | Epoch | Period | |---|---|---|---| | 0.01 | | Holocene | Quaternary | | 1.8 | | Pleistocene | Quaternary | | 2.6 | | | Quaternary | | 3.6 | | Piacenzian | Pliocene | | 5.3 | | Zanclean | Pliocene | | 7.2 | | Messinian | Pliocene | | 10 | | | | | 11.6 | | Tortonian | Miocene | | 13.8 | | Serravallian | Miocene | | 16.0 | | Langhian | Miocene | | 20 | | Burdigalian | Miocene | | 20.4 | | Aquitanian | Miocene | | 23.0 | | | Miocene | * *Mesozoic* | Picks Age (Ma) | Polarity | Epoch | Period | |---|---|---|---| | 70 | | Campanian | Late | | | | Santonian | Late | | | | Coniacian | Late | | | | Turonian | Late | | | | Cenomanian | Late | | | | Albian | Early | | | | Aptian | Early | | | | Barremian | Early | | | | Hauterivian | Early | | | | | Early | It has the advantage of being an objective unit, and its limits are isochronous (same times) on a global scale, differing as a function of the change in polarity. The problem that arises for these units is that the paleomagnetism of the rock can be primary or secondary, since the original magnetism can be altered by physical, chemical and biological processes (by bioturbation). ## Stratigraphic Discontinuities Concordancy of strata refers to a stratigraphic sequence of continuous or uninterrupted strata over time. The interruptions in the stratigraphic record, such as the absence of parallelism between layers (i.e., horizontality of layers) can be caused by several conditions or combinations of these conditions. By non-deposition of sediments, due to tectonism (deformations), by erosion, or combinations of these; in these cases, interruptions would imply interruptions in sedimentation. These interruptions involve the dimension of time involved in the event that they are known as: hiatuses, stratigraphic gaps, erosional voids, and diasterma. 1. **Paraconformity or stratigraphic discontinuity:** are parallel strata between them, where there was an interruption in sedimentation, and therefore a lack of time. 2. **Disconformity or erosive discordance with paleorelief:** these are parallel strata or deformed strata that are eroded, leaving a relief with respect to the overlying parallel strata or subparallel. 3. **Angular unconformity or tectonic discordance:** where deformed strata are observed in contact with underlying parallel strata. 4. **Unconformity or non-concordance:** when there are two lithologies in contact between igneous or metamorphic rocks with sedimentary rocks. 5. **Syntectonic discordance:** this involves a discordance that occurs as tectonism is occurring (uplift at the edge of a basin) in correlation with the zone where deformation does not occur. The surface that connects the side where the discordance is observed with the zone where there is continuity is known as the correlatively continuous surface. **Field observations:** * Lithological observations: These can be observed in conglomerates (basal) whose lithology is the same as the underlying rock or is composed of the same clasts. This suggests a time period in which there was exposure of the rock, followed by weathering and redeposition in a basin. Preservation of paleosols or with coal seams implies a long time to preserve organic matter. Lateritic soils or with (ferric minerals) exposed are oxidized, taking on an "orange" color, implying a time of exhumation and weathering; hardened soils or hardgrounds, phosphate levels, glauconite, manganese nodules condense time. * Paleontological observations: The absence of biostratigraphic zones or trace fossils from semi-consolidated substrate. * Geomorphological observations: Paleoreliefs that indicate uplift and subsequent erosion, paleokarsts that refer to carbonate rocks that are exposed and undergo dissolution by weathering. Other types of examples can be the differences in compaction observed in electrical profiles. ## Time Involved in Discordances Discordances are events that occur at a specific time and provide evidence of a certain magnitude of time in which they may occurr. There is no hierarchy when it comes to naming them, but they handle times ranging from short to long, hence there is a difference in the magnitude of the time involved. 1. **Hiatus:** This is presented as the absence of sediments or a time interval where there was no deposition. There can be erosional hiatuses when there has been removal of sediments or strata or depositional hiatuses when there is no sedimentation or lack of strata during that time. They generally have the largest dimension or magnitude of time involved. 2. **Stratigraphic gap** (this term should be placed like this, to avoid confusion with the sedimentary environment), is a period of non-sedimentation that was accompanied by one of erosion, and it could be interpreted as the sum of an erosional hiatus plus a depositional hiatus. This time could also be considered to have a large magnitude. 3. **Erosional void:** refers to sediments removed by erosion. 4. **Diastema:** refers to brief interruptions that cannot be readily dated. ## Stratigraphic Units To study the rocks in stratigraphy, they are treated or separated into units based on their characteristics or attributes, such as lithology, paleontological content (remains of past life preserved in the rocks), the time during which they were deposited, the magnetic characteristics, the chemical characteristics among others. Internationally, agreements are even made for some regulations (laws), which are adopted, or followed by countries, this is done for communication between geo-scientists and in a formal language. In this way, the international organizations establish the stratigraphic nomenclature: the North American Stratigraphic Code NASC (1983) and the International Stratigraphic Guide GEI (1984). * **NASC (1983):** These are regulations with articles that contain the principles of stratigraphic classification of North America, established by the North American Commission on Stratigraphic Nomenclature. Venezuela is governed by NASC (1983). * **GEI (1984):** These are guiding tools that aim to reach international consensus on the principles of stratigraphic classification. ### Lithostratigraphic units: units based on the lithology. * **NASC (1983):** In article 22, it mentions a lithostratigraphic unit as a defined body of sedimentary, extrusive igneous, metasedimentary or metavolcanic strata that is distinguished and delimited by its lithic characteristics and its stratigraphic position. * **NASC (1983)**: In general, a lithostratigraphic unit follows the principle of superposition of strata, is stratified, and tabular. In article 23, mentions that the limits of lithostratigraphic units are located in places of lithic change. * **NASC (1983):** In article 31, it mentions the nature of lithotopic units, which are defined as a body of rocks, predominantly intrusive, highly deformed and/or highly metamorphosed, which is distinguished and delimited by the characteristics of the rock. * **GEI (1984):** In contrast to lithostratigraphic units (of sedimentary rocks, since the code separates them), a lithotopic unit generally does not obey the principle of superposition of strata. Its contacts with other rock units can be sedimentary, extrusive, intrusive, tectonic or metamorphic. * **GEI (1984):** Defines a lithostratigraphic unit as the set of strata that constitute a unit, due to its predominance of a specific lithic type or a combination of lithic types, or by possessing other important lithic characteristics in common, which serve to group the strata. * **GEI (1984):** It can be composed of sedimentary, igneous or metamorphic rocks, or a combination of two or more of these rock types, consolidated or not, and a requirement is that there is a significant degree of homogeneity. * **Lithostratigraphic unit hierarchy:** | NASC (1983) | GEI (1984) | |---|---| | Supergroup | Group | | Group | Formation | | Formation | Member | | Member | Layer | | Layer | Layer | | | | **Example of how the GEI (1984) defines lithostratigraphic units** * **Group:** Two or more contiguous formations of higher order than the formation. It is a formal lithostratigraphic unit of rank immediately higher than that of a formation, which is generally made up of a succession of two or more contiguous formations with important common lithological features. * **Formation:** It is the formal fundamental unit of lithostratigraphy, of intermediate rank, which is made up of strata of sedimentary, intrusive or extrusive igneous rocks, or metamorphic rocks, or associations of these. * **Member:** formal lithostratigraphic unit of rank immediately lower than that of the formation, which is part of it and presents lithological characters that identify and distinguish it from adjacent parts. * **Layer of flow:** formal lithostratigraphic unit, smaller in size, of sedimentary origin, which can be distinguished lithologically from others, and whose thickness ranges from one centimeter to a few meters. * **GEI (1980):** To differentiate formal units from informal units, capitalize formal units and lowercase informal units. The GEI (1980) and CNE (1961) establish the Formation as the formal lithostratigraphic unit. **Example of how the NASC 1983 defines lithotopic units:** * **Complex:** Article 37 defines a Complex formally. A complex can be called a group of rocks of two or more genetic classes, e.g., igneous, sedimentary or metamorphic, with or without a very complicated structure (e.g., Boil Mountain Complex, Franciscan Complex) and, although it does not have an assigned rank, it is usually comparable to the assemblage or to the superassemblage and, therefore, it is usually named in the same way (Articles 41, 42). **Observations for the use of "complex"**: Identifying a set of diverse rocks as a complex is useful when it is not possible to map separately on ordinary scales each of the lithic components. A "Complex" does not have a designated rank, but it is usually comparable to the assemblage or the superassemblage, and therefore the term can be conserved if subsequent detailed maps distinguish some or all of lithotopic or lithostratigraphic units that compose it. ### Biostratigraphic units * For Rawson et al. (2002), biostratigraphy is based on the study of the distribution of fossils in-situ to recognize taxa or fossil distribution that are stratigraphically restricted and laterally extensive, making it possible to subdivide and correlate stratigraphic successions. * The fundamental principle of faunal succession states that fossils appear in a specific order in the geological record, establishing a way of relative dating of the same. Each stratum preserves a unique life because it is based on biological evolution, where species change over time or become extinct, they do not reappear in the fossil record (irreversibility). * Biostratigraphy can be used to establish stratigraphic correlations although they are in different geographic areas, the same layers will have the same fossil content (principle of lateral continuity). We must acknowledge that biostratigraphy does not depend on lithology but only on the set of fossils. * **Guide Fossils:** Many of the fossils used in biostratigraphy are called guide fossils that meet three characteristics: short lifespan, wide geographic distribution, and abundance. * Many marine microfossils meet these characteristics: foraminifera, radiolaria, calcareous nanoplankton, graptolites, conodonts, and on the continents, the microcopic component of larger plants can be used, such as pollen and spores. In both marine and continental environments, ostracods can be used. The study of fossils in biostratigraphy is important because they can be used in: determining relative age, stratigraphic correlation, for studies of paleoecology, bathymetry, paleotemperatures among others. * **Faunal or floral chart:** This is a graphic tool used in biostratigraphy to represent the distribution of different taxa fossils in diverse localities and geological strata. These charts are essential to understand the history of life and allow correlating stratigraphic units based on their fossil content. * **Biozones:** These are strata or a set of strata characterized by the content of certain taxa and allow grouping layers that share a similar fossil record, indicating that they formed during the same geological period. * **Biohorizons:** These are boundaries within biozones that are defined by the First Appearance (BPA) or the moment that a taxon appears for the first time in the fossil record or the Last Appearance (BUP) or the moment when a taxon disappears. * **Biostratigraphic zones:** Similar to lithostratigraphic units, international organizations establish biostratigraphic zones. * **In the following image, the similarities or differences of how different biozones are named by the NASC (1983) and GUI (1984) are shown. Some biozones are similar although their names differ and they are equivalent. For example, biozones of extension = hemerozones of taxa, biozones of coincident extension = concurrent hemerozones, lineage biozones, peak abundance= abundance. The only biozone considered by the GUI 1984 is the interval zone of the last appearance and the first appearance of two taxa.*  ### Chronostratigraphic units * Chronostratigraphic units refer to the rock bodies that formed in a determinate time interval of geological history. * **NASC (1983)**: These are defined as a body of rock established to serve as time reference material for all the rocks formed during the same time frame. In article 69, the hierarchy of chronostratigraphic units is: eonotheme, erathem, system, series, and stage. * **Chronostratigraphic units vs. geochronological units:** The chronostratigraphic unit refers to the rock body, while the geochronological unit refers to the time interval. * **Chronostratigraphic unit hierarchy:** | Chronostratigraphic | Geochronological | |---|---| | Eonotheme (e.g. Phanerozoic) | Eon | | Erathem (e.g. Mesozoic) | Era | | System (e.g. Cretaceous) | Period | | Series (e.g. Upper Cretaceous) | Epoch | | Stage (e.g. Campanian, Albian, Cenomanian, Turonian, Maastrichtian, ...)| Age | | | Chron | | Chronozones | | * A geochronological unit is not a material unit, but it corresponds to the time span of a chronostratigraphic unit. ## Facies in Stratigraphy Gressly in 1838 introduced the concept of facies, which he defined as the lithological and paleontological aspects of a stratigraphic unit. Reguant in 1971 defines the concept of facies in an abstract form as the set of lithological characteristics (composition, texture, and sedimentary structures) and paleontological characteristics that define those rocks and allow them to be distinguished from others. The discussion and revision of this concept allow them to be subdivided into "descriptive" facies and those that have "chronostratigraphic reference". Selley in 1970 defined a facies as a set of sedimentary rocks that can be defined and separated from others by its geometry, lithology, sedimentary structures, paleocurrent distribution, and fossils. Bosellini et al. (1989) take the facies term to its extreme end, defining it as a depositional unit of fundamental and lesser rank, considering it as: a sedimentary body of metric thickness, composed of one or more strata and characterized by its lithological features (composition and texture) and stratigraphic features (thickness, geometry, sedimentary structures, and fossils). * **Facies with Chronostratigraphic reference:** refer to facies that imply genetic features applicable to materials with a certain age. * *Example: Keuper Facies "brittle shale", which are deposits of continental origin of the Triassic Period (Ladinian and Rhaetian) formed by clays, evaporites, some sandstone levels that occur in extensive areas within the same chronostratigraphic interval.* * *Facies lithological or Lithofacies*: refer to the set of lithological aspects (not paleontological) of a set of strata and by extension to the physical-chemical conditions (not biological) depositational. * **Example:** Oolitic limestone facies, glauconitic sandstone facies, etc. * *Facies referred to by the paleontological content or Biofacies:* it refers to the paleontological aspects and to the biological conditions prevailing during the deposition. * **Example:** Facies of nummulites (which are facies where large benthic foraminifera fossils predominate) * **Microfacies:** refers to the microscopic observation of the lithological, paleontological, and correlatively to the genetic conditions that controlled their deposition. * **Electrofacies:** refer to certain characteristics of the materials in the subsoil obtained from the responses of the diagrams of well profiles. This profile is compared with rock cores to be able to extrapolate to the rest of an area in the subsoil, and it is very useful for the determination of a paleogeographic, paleoenvironmental map after stratigraphic correlation of the area. * **Seismic Facies:** refer to the set of properties observable in a seismic profile for a stratum or set of strata. They are controlled by the lithofacies and above all by the geometry of the stratification. The properties to highlight are: the continuity of the seismic reflectors, the amplitude, the frequency, the configuration, and the velocity of the interval. ## Paleogeographic Reconstruction Paleogeography is the branch of geography that studies the distribution of terrestrial and marine masses throughout the history of the Earth. Paleogeographic maps are a type of geological map that is made for a specific time or period. They are created from facies maps of the same region where the reconstructed geography for a specific time is represented. Facies are reinterpreted based on the sedimentary environment, bathymetry, and morphology of the relief. Data on paleocurrents can also be added. The reconstruction of the geographic conditions of the past is based on data from several disciplines such as stratigraphy, sedimentology, paleontology, and paleomagnetism. It includes the study of significant events such as the formation or fragmentation of supercontinents, such as Pangea, and also drift events of the continental plates, tectonics. This can be used to reconstruct the paleogeography of the Caribbean with implications for its biodiversity, biological or biogeographical. ## Reconstruction of Paleoenvironments, Main Sedimentary Environments: (Summary) To determine or study paleoenvironments, the recent study of environments is taken into account. Hutton's famous phrase "the present is the key to the past" refers to the fact that the events that happen today in recent sedimentary environments, may have occurred in the past and it can be extrapolated to the past. The study of environments in general is complex because it depends on many factors, even if the mechanisms that create them are similar. Each sedimentary environment is unique and depends on the geographic location where it is created, the climate, tectonics, rate of sediment input and erosion, changes in sea level, even orbital parameters, since it is subject to the Earth-Moon-Sun dynamics, in this particular case, they generate tides, in addition to precessional movements. obliquity and eccentricity that generate cyclical patterns. * **Why are sedimentary environments studied?** Some reasons include: * Understanding the history of the Earth. * Scientific research. * Reconstruction of past environments. * Understanding paleoecology. * Understanding paleogeography, and even paleoclimatology. * The management of risk and mitigation of natural hazards such as landslides or floods. * The search for and evaluation of any potential natural resources such as those in the oil, mining, clay industries, among others. * **Diatomite:** A type of sedimentary rock composed of diatom fossils (microscopic algae) that has multiple uses and is common, even in our everyday lives: it serves as a mild abrasive in toothpaste and facial scrubs, a binder in paint manufacturing, an absorbent for oil spills and chemicals, for water filter stones, as a refractory and thermal insulator, for dynamite, for improving the efficiency of catalysts, as an anti-caking agent in powder, as a fertilizer in agriculture, as a dewormer, to preserve moisture in seeds, among other uses. * **Discovering Mineral Deposits:** It is possible to study sedimentary environments to search for deposits. * **Studying the Earth's Past:** By Studying past sedimentary enviroments we can also learn about the climate and life of the Earth in the geologic past.