Sedimentary Rocks (BOLD)

Texture of Shale

- typically exhibits varying degrees of fissility breaking into thin layers, often splintery and usually parallel to the otherwise indistinguishable bedding plane because of parallel orientation of clay mineral flakes.

Composition of Shale

Clay minerals and quartz

Gray

Color of shale

clast size

Conglomerates are also classified by the dominant ____. Granule conglomerate 2-4 mm Pebble conglomerate 4-64 mm Cobble conglomerate 64-256 mm Boulder conglomerate >256 mm

Clast composition

Conglomerates are classified for the lithologies of the clasts Monomict - clasts with only a single lithology Oligomict - clasts of only a few different lithologies Polymict - clasts of many different lithologies Intraformational - clasts derived from the same formation in which they are found Extraformational - clasts derived older rocks than the formation in which they are found

sedimentary environments

Conglomerates are deposited in a variety of ___

Shallow marine

Conglomerates are normally present at the base of sequences laid down during marine trangressions above an unconformity, and are known as basal conglomerates. They represent the position of the shoreline at a particular time and will be diachronous.

fluvial

Conglomerates deposited in ___ environments are typically well-rounded and well-sorted. Clasts of this size are carried as bedload and only at times of high flow-rate. The maximum clast size decreases as the clasts are transported further due to attrition, so conglomerates are more characteristic of immature river systems.

coral atolls

Dolomitization of calcite also occurs at certain depths of _____ where water is undersaturated in calcium carbonate but saturated in dolomite. Convection created by tides and sea currents enhance this change. Hydrothermal currents created by volcanoes under the atoll may also play an important role.

glacial

Glaciers carry a lot of coarse-grained material and many ___ deposits are conglomeratic. Tillites, the sediments deposited directly by a glacier, are typically poorly-sorted, matrix- supported conglomerates. The matrix is generally fine-grained, consisting of finely milled rock fragments.

Classification of Conglomerate

In addition to the factors described in this section, conglomerates are classified in terms of both their rounding and sorting.

Deepwater marine

In turbidites, the basal part of a bed is typically coarse-grained and sometimes conglomeratic. In this setting, conglomerates are normally very well sorted, well-rounded and often with a strong A-axis type imbrication of the clasts.

Sedimentary rock

Is a type of rock that is formed by sedimentation of material at the Earth's surface and within bodies of water.

erosional landforms

Limestone is partially soluble, especially in acid, and therefore forms many ____. These include limestone pavements, pot holes, cenotes, caves and gorges. Such erosion landscapes are known as karsts.

Jovan Cvijic

The geographer ____ (1865-1927) was born in western Serbia and studied widely in the Dinaric Kras region.

karren or lapiez

The karstification of a landscape may result in a variety of large or small scale features both on the surface and beneath. On exposed surfaces, small features may include flutes, runnels, clints and grikes, collectively called _____.

Solnhofen Limestone

The original source for lithographic limestone was the ___ named after the quarries of ___ where it was first found.

compaction

The process in the rock cycle which forms shale is _____.

sedimentary environment

The setting in which a sedimentary rock forms is called the

diagenesis

The term _____ is used to describe all the chemical, physical, and biological changes, including cementation, undergone by a sediment after its initial deposition, exclusive of surface weathering.

sedimentary facies

The typical rock formed in a certain environment is called its ____.

astronomic cycles

This cyclic nature was caused by cyclic changes in sediment supply and the sedimentary environment. Most of these cyclic changes are caused by __.

"Other" sedimentary rocks

This fourth miscellaneous category includes rocks formed by Pyroclastic flows, impact breccias, volcanic breccias, and other relatively uncommon processes.

siliceous sinter

Travertine forms from geothermal springs and is often linked to siliceous systems which form ____.

Composition of Sandstone

Typically quartz and/or feldspar (on earth); lithic fragments are also common. Other minerals may be found in particularly immature sandstone.

fanglomerate

When a series of conglomerates accumulates into an alluvial fan, in rapidly eroding (e.g. desert) environments, the resulting rock unit is often called a ___.

calcareous sinter

When deposits are apparently devoid of any biological component, they are often referred to as _____.

Evaporite formations

____ need not be composed entirely of halite salt. In fact, most ___ do not contain more than a few percent of evaporite minerals, the remainder being composed of the more typical detrital clastic rocks and carbonates.

Iron-rich sedimentary rocks

_____ are composed of >15% iron; the most common forms are banded iron formations and ironstones

Phosphatic sedimentary rocks

_____ are composed of phosphate minerals and contain more than 6.5% phosphorus; examples include deposits of phosphate nodules, bone beds, and phosphatic mudrocks

Ooids

_____ are most commonly composed of calcium carbonate (calcite or aragonite), but can be composed of phosphate, chert, dolomite or iron minerals, including hematite.

Secondary sedimentary structures

_____ are structures in sedimentary rocks which formed after deposition.

Paraconglomerates

_____ consist of a matrix-supported rock that contains at least 15% sand-sized or smaller grains (<2 mm), the rest being larger grains of varying sizes.

Chemical sedimentary rock

_____ forms when mineral constituents in solution become supersaturated and inorganically precipitate.

holokarst

_____ i.e. karst developed at whole as it is Dinaric region along eastern Adriatic coast comprises deep in the inland of Balkan Peninsula

Primary sedimentary structures

formed during deposition

Organic-rich sedimentary rocks

have significant amounts of organic material, generally in excess of 5% total organic carbon.

conglomerate

A ___ is a rock consisting of individual clasts within a finer-grained matrix that have become cemented together. __ are sedimentary rocks consisting of rounded fragments and are thus differentiated from breccias, which consist of angular clasts. Both ___ and breccias are characterized by clasts larger than sand (>2 mm).

karst fenster

A _____ is where an underground stream emerges onto the surface between layers of rock, cascades some feet, and then disappears back down, often into a sinkhole.

Montserrat, near Barcelona

A spectacular example of conglomerate can be seen at ___. Here erosion has created vertical channels giving the characteristic jagged shapes for which the mountain is named ( _____ literally means "jagged mountain").

Notable karst areas

Africa Madagascar Poland Romania Serbia Madagascar Asia Scotland Slovakia Slovenia Spain China

Compositional classification schemes

Alternately, sedimentary rocks can be subdivided into compositional groups based on their mineralogy.

calcareous sinter

Although sometimes regarded as a distinct carbonate deposit, ____ formed from ambient temperature water can be considered a sub-type of tufa.

Genetic classification schemes

Based on the processes responsible for their formation, sedimentary rocks can be subdivided into four groups: clastic sedimentary rocks, biochemical (or biogenic) sedimentary rocks, chemical sedimentary rocks and a fourth category for "other" sedimentary rocks formed by impacts, volcanism, and other minor processes.

Historical mining terminology

Before the mid 19th century, the terms slate, shale and schist were not sharply distinguished. In the context of underground coal mining, shale was frequently referred to as slate well into the 20th century.

metaconglomerate

Metamorphic alteration transforms conglomerate into _____.

sedimentary basins

Places where large-scale sedimentation takes place are called ____.

clastic

Sandstones are ____ in origin (as opposed to either organic, like chalk and coal, or chemical, like gypsum and jasper). They are formed from cemented grains that may either be fragments of a pre-existing rock or be mono-minerallic crystals.

Sediment transport and deposition

Sedimentary rocks are formed when sediment is deposited out of air, ice, wind, gravity, or water flows carrying the particles in suspension.

oolitic limestone

Some exemplar ____, a common term for an oolite, was formed in England during the Jurassic period, and forms the Cotswold Hills on the Isle of Portland with its famous Portland Stone, and part of the North Yorkshire Moors.

principle of superposition

That new rock layers are above older rock layers is stated in the ____. There are usually some gaps in the sequence called unconformities.

Chalk Group

The ___ is a European stratigraphic unit deposited during the late Cretaceous Period.

rate

The ____ at which sediment is deposited differs depending on the location.

color of a sedimentary rock

The _____ is often mostly determined by iron, an element with two major oxides: iron(II) oxide and iron(III) oxide.

American Lithographic Stone Company

The _____ was organized in Louisville, Kentucky in late 1868. It initially focused its operation on quarries in Overton County, Tennessee, but shortly before 1900, it opened a quarry at Brandenburg, Kentucky.

Sandstone

___ (sometimes known as arenite) is a sedimentary rock composed mainly of sand-sized minerals or rock grains. Most ___ is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, ____ may be any color, but the most common colors are tan, brown, yellow, red, gray and pink, white.

Lacustrine tufas

___ are generally formed at the periphery of lakes and build up phytoherms (freshwater reefs) and stromatolites. Oncoids are also common in these environments.

Fossils

___ can both be the direct remains or imprints of organisms and their skeletons.

merokarst

___ developed imperfectly with some karstic forms as it is in eastern Serbia

Arkose

___ is a detrital sedimentary rock, specifically a type of sandstone containing at least 25% feldspar. Arkosic sand is sand that is similarly rich in feldspar, and thus the potential precursor of arkose. The other mineral components may vary, but quartz is commonly dominant, and some mica is often present.

Karst topography

___ is a landscape shaped by the dissolution of a layer or layers of soluble bedrock, usually carbonate rock such as limestone or dolomite.

Calcareous speleothems

___ may be regarded as a form of calcareous sinter. They lack any significant macrophyte component due to the absence of light, for this reason they are often morphologically closer to travertine or calcareous sinter.

Coquina

____ (Spanish, "cockle") is an incompletely consolidated sedimentary rock. ___ was formed in association with marine reefs and is a variety of "coral rag", technically a subset of limestone. _____ is mainly composed of mineral calcite, often including some phosphate, in the form of seashells or coral.

Oolite

____ (egg stone) is a sedimentary rock formed from ooids, spherical grains composed of concentric layers. The name derives from the Hellenic word òoion for egg. Strictly, ____ consist of ooids of diameter 0.25-2 mm; rocks composed of ooids larger than 2 mm are called pisolites.

Diatomaceous earth

____ also known as diatomite or kieselgur, is a naturally occurring, soft, siliceous sedimentary rock that is easily crumbled into a fine white to off-white powder. It has a particle size ranging from less than 1 micron to more than 1 millimeter, but typically 10 to 200 microns.

Tufa columns

____ are an unusual form of tufa typically associated with saline lakes. They are distinct from most tufa deposits in that they lack any significant macrophyte component; this is due to the salinity excluding mesophilic organisms.

Evaporite sedimentary rocks

____ are composed of minerals formed from the evaporation of water.

Alluvial deposits

____ are formed in areas of high relief and are typically coarse-grained.

Evaporites

____ are water-soluble mineral sediments that result from the evaporation of bodies of surficial water. ___ are considered sedimentary rocks.

Orthoconglomerates

____ consist of a clast-supported rock with less than 15% matrix of sand and finer particles.

Carbonate rocks

____ dominantly consist of carbonate minerals like calcite, aragonite or dolomite.

Shale

____ is a fine-grained, clastic sedimentary rock composed of mud that is a mix of flakes of clay minerals and tiny fragments (silt-sized particles) of other minerals, especially quartz and calcite. The ratio of clay to other minerals is variable.

Travertine

____ is a form of limestone deposited by mineral springs, especially hot springs. ____ often has a fibrous or concentric appearance and exists in white, tan and cream- colored varieties. It is formed by a process of rapid precipitation of calcium carbonate, often at the mouth of a hot spring or in a limestone cave. In the latter it can form stalactites, stalagmites and other speleothems. It is frequently used in Italy and elsewhere as a building material.

Geyserite

____ is a form of opaline silica that is often found around hot springs and geysers. Botryoidal _____ is known as fiorite. It is sometimes referred to as sinter.

Limestone

____ is a sedimentary rock composed largely of the minerals calcite and/or aragonite, which are different crystal forms of calcium carbonate (CaCO3).

Chalk

____ is a soft, white, porous sedimentary rock, a form of limestone composed of the mineral calcite. Calcite is calcium carbonate or CaCO3. It forms under relatively deep marine conditions from the gradual accumulation of minute calcite plates (coccoliths) shed from micro-organisms called coccolithophores.

Tufa

____ is a variety of limestone, formed by the precipitation of carbonate minerals from ambient temperature water bodies. Geothermally heated hot-springs sometimes produce similar (but less porous) carbonate deposits known as travertine. It is sometimes referred to as (meteogene) travertine; care must be taken when searching through literature to prevent confusion with hot spring (thermogene) travertine. Calcareous ___ should not be confused with tuff, a porous volcanic rock with parallel etymological origins.

Lithographic limestone

____ is hard limestone that is sufficiently fine-grained, homogeneous and defect free to be used for lithography. Geologists use the term lithographic texture to refer to a grain size under 1/250 mm. The term sublithographic is sometimes used for homogeneous fine-grained limestone with a somewhat coarser texture.

Magnesite

_____ is magnesium carbonate, MgCO3. Iron (as Fe2+) substitutes for magnesium (Mg) with a complete solution series with siderite, FeCO3. Calcium, manganese, cobalt, and nickel may also occur in small amounts. Dolomite, (Mg,Ca)CO3, is almost indistinguishable from ____.

Dolomite

_____ is the name of a sedimentary carbonate rock and a mineral, both composed of calcium magnesium carbonate CaMg(CO3)2 found in crystals.

Clastic sedimentary rocks

______ are composed of silicate minerals and rock fragments that were transported by moving fluids (as bed load, suspended load, or by sediment gravity flows) and were deposited when these fluids came to rest.

Carbonate sedimentary rocks

_______ are composed of calcite (rhombohedral CaCO3), aragonite (orthorhombic CaCO3), dolomite (CaMg(CO3)2), and other carbonate minerals based on the CO32- ion.

Pseudokarsts

_______ are similar in form or appearance to karst features, but are created by different mechanisms. Examples include lava caves and granite tors—for example, Labertouche Cave in Victoria, Australia and paleocollapse features.

Siliciclastic sedimentary rocks

_______, as described above, are dominantly composed of silicate minerals.

Siliceous sedimentary rocks

are almost entirely composed of silica (SiO2), typically as chert, opal, chalcedony or other microcrystalline forms.

Biochemical sedimentary rocks

are created when organisms use materials dissolved in air or water to build their tissue.