LAB

Question 1

Conglomerate/Breccia nomenclature:

Answer 1

“support, clast-type, average size of clasts, conglomerate/breccia”

EX: Clast-supported quartzite pebble conglomerate

Question 2

3D QFL diagram

Answer 2

%mud: <5%= arenites, 5>%mud<50%=wackes, %mud>50%=mudstones QFL: %qtz: %qtz>90%=qtz arenite, 75-90%=sublithic, sub-arkosic, <75%-arkosic or lithic

Question 3

4 types of erosional bedding plane markings

Answer 3

1. ) Sole markings: These are extruding features on the base of sandstones into shales (non-exclusive) and derived from erosional tools scraping the bed bottom.
2. ) groove casts: “scraping” of tools along the floor, creates chevron or v shape dipping down-current.
3. ) Saltation: bouncing…
4. ) flute casts: These are shaped like yardangs and form in a similar way. The fat tail indicates flow direction.

Question 4

Allochems

Answer 4

These include ooids, pisoids, peloids, oncoids, and intrachlasts. It includes any carbonate clasts with D>fine sand (63microns)

Question 5

Allochthonous carbonates

Answer 5

This is all carbonates with coarse grains (10% has D>2mm) that are not organically bound at deposition indicating that grains were transported.

If it is grain supported it is a packstone.

If it is matrix supported grainstone.

If there are more than 10% grains then it is a wackestone.

If there are less than 10% grains than it is a mudstone.

Question 6

Arenites NEED PIC

Answer 6

Sandstones that are composed of distinct grains and cement with a maximum of 5% mud.

Question 7

Authegenic minerals

Answer 7

Minerals produced at the surface. Minerals precipitated through biologic, supersaturation, oxidation, or other processes.

Question 8

Ball and Pillow Structures

Answer 8

Seemingly abnormal ball or kidney shaped bulbous structures protruding the base of a bed and likely derived from the liquification of surrounding sediment.

Question 9

Bedding Structure Matrix

Answer 9

Beds are either Parallel or Nonparallel and either Continuous or discontinuous. The three kinds of lineations apparent are Even, Wavy, and curved.

Question 10

Bedforms

Answer 10

Mounds or troughs of loose sediment on a mobile bed forming @ sediment and fluid interface. They describe the relation of strata and are often similar in size/shape, perhaps show a pattern.

Turbulence produces bedforms.

Question 11

Beds

Answer 11

Tabular or lenticular layers of sediment that share lithological, textural, or structural unity and have a heterogeneous nature when compared to other beds.

These include Sediment units, subdivisions, and amalgamation surfaces.

laminae<1cm thick

Structures are used to describe how layers are configured and aid identification of environments/depositional processes.

Question 12

Bernoulli’s Principle

Answer 12

Derived from the conservation of energy and the principle of continuity where:

KE+PE+P(aka work)=Constant

If the path is obstructed by a grain and therefore V(flow) increases (see principle of continuity) and over a dx the PE is constant/~0 then the KE increases when traversing over the grain and therefore P (pressure) decreases. This forms hydraulic lift.

Question 13

Biogenic Structures

Answer 13

These are the trace fossils of burrowing, boring, feeding, locomotion, cut-and-fill caving, and arise from bioturbation, biostratification (stromalites), bioersion, and excrement.

Vertical trace fossils indicate harsher environments that are more likely to be eroded.

Question 14

Carbonate Rocks

Answer 14

Rocks that are primarily composed of CO₃ minerals/sediments. These include calcite, aragonite, and dolomite that are precipitated our of solution.

These are the most abundant chemical/biochemical rock and accounts for ~20-25% of all sedimentary rocks.

Question 15

Cataclastic Breccia

Answer 15

Refers to breccias formed due to land movement.

Landslide/Slump breccias form due to the tension of sliding material

Tectonic Breccias form from gouge

Collapse breccias are from cave-ins and other forms of ground failure

Question 16

Climbing Ripples

Answer 16

During the de-escalation of flow ripples will stop migrating and start “mounding” Therefore downward flow will be up-dip. They form non-tangential and tabular cross-bredding.

Question 17

Conglomerates/Breccias:

Answer 17

Rocks that are primarily composed of lithic fragments over 4mm (pebble size) (>10%). If they are angular then it is considered a breccia. If they are more mature and rounded then they are conglomerates. Clast supported refers to if the individual clasts are touching and create the structure. Matrix supported refers to the concept of the clasts being suspended in the fine grained matrix material.

In cut sections clasts may appear overly touching.

Question 18

Convolute Bedding and Laminations

Answer 18

Folding and crumpling of beds with irregular mircro anti/synclines that are restricted to a finite subdivision of the bed (~.05-.25 m) and the upper/lower bounds are clearly not convolute. This is a form of soft sediment deformation but it is concurrent to deposition not post post-depositional like tectonics are. Commonly with slumps on slopes and water saturated sediments.

Question 19

Coquina

Answer 19

A mechanically sorted fossil hash

Question 20

Debris flow deposits

Answer 20

Unsorted, chaotic (sorting requires turbulence), matrix supported, lacks cross-stratification and occasionally shows reverse grading

Question 21

Desiccation

Answer 21

These structures show occasional wetting within arid environments and includes mudcracks, raindrops, salt casts, and teepee structures.

Question 22

Dimensionless numbers

Answer 22

Numbers that describe a state change for the participants of the system.

Question 23

Dunham Carbonate Classification

Answer 23

A classification system that enables classification via hand specimen that emphasizes the grain packing, micrite abundance, and grain binding.

Mud-supported rocks include mudstone (<10% grains) and wackestone (>10% grains)

Grain supported rocks include packstone (>1% mud) and grainstone (<1%mud)

Allochthonous is for coarse sediment not bound at deposition wheras autochtonoous is for coarse grains that are bounded at deposition.

Question 24

Epiclastic Breccia/Conglomerate

FIND EXAMPLE

Answer 24

Epiclastic conglomerate/breccia: An extraformational/intraformational rock that formed from a non-specific weathering and transport process.

Question 25

Erosional Structures

Answer 25

These include sole marks which show a unidirectional flow that drags a particle across the base. Direction of flow cannot be determined. Tool marks refer to dragging of "tools" on the surface. Flute casts refer to the scouring of eddies behind large clasts that are not entrained the deepest part of the cast is at the front of the flow. Paleochannels: These cross-cut bedding and can be tidal, underwater, and fluvial. Scour and Fill: These are small lenses of coarse material whose long axis indicates flow direction where the bulbous end of the lens exists.

Question 26

Feature of immature clasts

Answer 26

Poor sorting, angular grains composed on relatively unstable minerals.

Question 27

Features of mature clasts

Answer 27

homogenous composition, well rounded, well sorted

Question 28

Feldspathic Arenite AKA Arkose

Answer 28

Less than 75% of the clasts are qtz and there is more spar than lith. They are generally immature and form clay-rich arenites. They often form on stable continental shelves/alluvial fans or in-situ when granite decays. They are promoted by arid/cold environments and were more common from Paleozoic and Mesozoic times.

Question 29

Flaser Bedding

Answer 29

This is describing a bed form where there is a mixture of mud accumulates in the troughs of the cross strata in the intrabedding portions of the rock. Indicates that the hydraulic conditions favored sand preservation during episodic flows and variable flow conditions

Question 30

Froude Number

Answer 30

A dimensionless unit that describes how a surface wave passes through a liquid. The denominator describes the velocity of a surface wave through water and the numerator is the velocity of flow. Therefore a F_r\<1 means that the wave's velocity is greater than the flow's. F_r=V/(gD)^.5 D=water depth

Question 31

Grading

Answer 31

Normal Grading describes beds that are larger grained at the base and grade into finer sediments. Reverse grading indicates that the largest grains are at the top of the bed and can occur due to kinetic sieving and dispersive pressures.

Question 32

Grain flow deposits

Answer 32

Kinetic sieving causes reverse grading. Generally well sorted, and form wedge shapes with the upper surface = angle of repose. In comparison to eolian settling this increase in thickness downwards. They are often adjacent to settling deposits though.

Question 33

Hjulstrom Diagram

Answer 33

A diagram that shows three phases of sediment transport and describes the maximum diameter of a particle that be entrained within a flow based on flow velocity. At small diameter the erosion potential decreases (v for entrainment) because the fine particle's develop stronger van-der-waals cohesive forces. This occurs when particles diameter\<100 microns. The curve is calibrated for D=1 m and SiO2 particles.

Question 34

hummocky cross stratification

Answer 34

Undulating cross-stratification that are both concave-up (swales) and convex-up (hummocks) with beds gently cutting one another and bounded by bioturbation. Includes large circular surface features. Basically they are mounds that occur within fine sands with both oscillatory and unidirectional flows. It is believed to be caused by chaotic storm flows.

Question 35

imbrication

Answer 35

These are flat pebble "shingles" that indicate the flow direction. These indicate a rather regular and persistent flow.

Question 36

Laminar flow

Answer 36

Particles move relatively parallel to each other and the overall flow vector. It is supported by a low reynolds number.

Question 37

Lenticular Bedding

Answer 37

This is characterized by discontinuous mud lenses and can indicate tidal planes, deltas, shallow shelfs, that favor mud preservation. In general the flow is episodic. Often paired with flaser bedding.

Question 38

Liquified flow deposits

Answer 38

Dish structures (concave up "dishes") Convolute laminae ("mushroom" shapes) Flame structures (similar to convolute but not yet wider at the peak) Mounds and vertical structures: "mud volcanoes" where the water was escaping the sediment

Question 39

Lithic Arenites

Answer 39

Siliclastic rocks with a large quantity of rock fragments. Often immature, angular grains and indicates shallow marine enviroments or fold-thrust belts.

Question 40

Marl

Answer 40

A mudstone with interlayers of siliclastic mud or silt that is torigenous.

Question 41

Maturity of sediment

Answer 41

Maturity is the extent to which grains have reached their final weathering product for a given environment.

Question 42

Migration of Ripples

Answer 42

Ripples migrate due to the avalanching on the lee-side of the slope. They produce cross stratification that is either linear (2D ripples) or concave (3D ripples). In lower flow regimes the small avalanching indicates down stream and in upper flow lee-side avalanching is up stream

Question 43

Mudstones

Answer 43

Fine grained siliclastic rocks with more than 50% of the grains smaller than 1/256 mm. Phyllosilicates (kaolinite, illite, and smectite) and quartz are the primary mineral components. They are indicative of deep ocean/lakes where the turbulence is low. Claystones (D\<4 microm) Siltstone (4-63 microns) Shale: fissile bedded/brittle mudrocks. often with pyrites and other sulfides. Argillite: a low-grade metamorphosed mudstone

Question 44

Name the size range for clay, silt, and sand

Answer 44

Clay: D8 (too small to see) Silt: .004 Sand: .06

Question 45

Ooids

Answer 45

A general term describing carbonate grains that grow as rims on other particles. The term particularly describes rims with concentric grains D\>63 microns. Ooze has D\<4 microns. They tend to form in high energy environments like warm water reef shelves.

Question 46

Peloids

Answer 46

Grains of micro or cryptocrystalline calcite/aragonite without a coherent internal structure. These are often composed of pellets and lack concentric layering. .03

Question 47

Phi-scale

Answer 47

phi=-log₂d so d=2^(-phi) In general when phi\>0 the size decreases reflecting the tendency to see small and not large particles. The levels of phi define the different clasts in a sedimentary rock and are markers for how sediment behaves when acted upon by an external shearing force.

Question 48

Pisoids

Answer 48

an ooid with a D\>2 mm

Question 49

Porosity and Permeability

Answer 49

Porosity describes how much of the rock is filled with a fluid, either air or liquid. Permeability is the measure for how rapidly a fluid moves through a rock.

Question 50

Principle of Continuity

Answer 50

Q₁A₁=Q₂A₂ This says that the net mass going through an area is constant. It assumes that there is no collection of fluid and that it is incompressible.

Question 51

Provenence

Answer 51

The paleosetting of a sediment used to derive its origin.

Question 52

Proximal vs. Distal Turbidites

Answer 52

Proximal turbidites refers to turbidites that have prominent A-C horizons and form on or near the continental shelf. They are up to a meter thick. Distal turbidites have more intense C-E layers and refers to deeper ocean turbidites.

Question 53

Reading Cross Sections

Answer 53

Grain Size: The wider the base the larger the grains. Beds: Dark lines indicate beds. Amalgamation Surface: Indicated by a dotted line

Question 54

Reynolds Number

Answer 54

=inertial F/Viscosity= U(flow)\*L\*rho/(dynamic viscosity) where: L~depth of flow F_i = intertial forces and is related to the momentum of the fluid. U=avg velocity It is a dimensionless unit describing laminar (re\<500) and turbulent flow (500) The shift from laminar to turbulent flow is determined by boundary conditions of the flow.

Question 55

Ripple Classification

Answer 55

2D ripples: Parallel lines without lee-side indicates oscillatory motion. These create planar bedding. Up dip on the _bed sets_ indicates the flow direction. This is the down dip direction on the interbedded curves that show the migration of ripples. 3D ripples: Tangential, trough lines, indicates turbulence. These create trough stratification. They indicate higher flow velocities. In cross section 2d ripples will have planar beds in one direction and bed sets in the other. 3d ripples will have bed sets in one direction and trough cross strata in the other.

Question 56

Sandstones

Answer 56

Primarily mineral grains of sand size. Arenites are sand+cement, wackes are sand+silt/mud.

Question 57

Sediment Classes

Answer 57

Clastic: Physically transported and accumulated sediment Carbonates: chemical/biorganic carbonate formation and consists of either unaltered primary sediments or secondary, altered, sediments. Other biogenic sediments: cherts, diatomites Chemical Sediments: Evaporites

Question 58

Sediment Maturity

Answer 58

Sphericity, Roundness/angularity (wind is very effective and depleting angles), and composition. A very mature sediment indicates that a greater amount of work has been done of the grains.

Question 59

Sequence of bedforms in laminar flow

Answer 59

planar beds, ripples, sand waves, dunes. Steep side shows flow direction.

Question 60

Shooting/supercritical flow

Answer 60

When Fr\> 1 and there is not upward flow.

Question 61

Siliciclastic Sedimentary Rocks

Answer 61

A broad group of sedimentary rocks (~75% of all) that are primarily composed of silica rich minerals. These include sandstones, shales, and conglomerates.

Question 62

Siliciclastic cements

Answer 62

Silica overgrowths: These are characterized by the quartz grains having extended, slightly modified boundaries, but also exhibit homogenous extinction angles. Microcrystalline fabric: "mini-geodes"

Question 63

Slump Structures

Answer 63

Also known as synsedimentary folds/faults that are derived from less compacted sand/mudstones.

Question 64

Solution Breccia

Answer 64

When a solution dissolves the host rock and only the insoluble rocks remain to form the fragments present within the breccia.

Question 65

Stoke's Law

Answer 65

The terminal velocity of a settling particle determined from the balance of gravity and drag forces. It can also be said to be proportional to the cross-sectional area of a flow (pressure effects) and the amount of fluid a particle displaces (drag) U=cD² = (1/(18\*μ)[(ρ_s-ρ_f)\*g\*D²] Where: U=terminal V of the falling particle D=_spherical_ diameter c=constant=f(viscosity, rho(fluid),rho(solid)

Question 66

stomalites

Answer 66

These are organic silt laminations within LS that form from algal plumes. If the laminations are too poor to recognize it is called a thrombalite.

Question 67

Structureless/Massive Bedding

Answer 67

Bedding that shows a lack of internal structure that have little viable explanations to their creation. Oftentimes apparent massive bedding shows structures following x-ray analysis or acid staining.

Question 68

Synesis and mudcracks

Answer 68

Subaqueous and subariel mudcracks that form from the alignment of clay minerals.

Question 69

Terms of bedforms (flow separation, attachment, eddy erosion)

Answer 69

Flow separation: The point where the flow lines depart from the peak of the ripple Attachment: the intersection of the falling flow line with the proceeding ripple Eddy erosion is the scouring that is caused by the turbulence of eddies.

Question 70

Tranquil flow

Answer 70

When Fr \< 1 and waves can move up the flow

Question 71

turbidite anatomy

Answer 71

Head: The erosive part of the flow that scours the base of the bed. Body: A steady and uniform portion of flow that begins depositing a and b layers of the bouma sequence. It flows faster than the head. Tail: Dilute part of the flow that can auto suspend fine particles.

Question 72

Turbidite/Bouma Sequence

Answer 72

.2-.4 m deposits derived form turbidity currents with an a-layer that has a scoured base, massive granular sands, and normal grading of coarse particles. b layer is planar bedding from the upper flow regime. c layer has ripple structures and represents the shift from upper to lower flow regimes. d is laminated silts with tail ripples (lower flow) e is pelogic (oceanic) and hemipelogic muds.

Question 73

turbidity flows

Answer 73

A type of gravity flow derived from sediment accumulation following seasonal floods, storms, quakes, or tsunamis and characterized by a shift from plastic to fluid flow. It has low viscosity, high turbulence, and lacks an internal structure.

Question 74

Turbulent flow

Answer 74

A field of the flow lines created within this type of flow show no pattern of molecular flow and may not align with the average flow vector. It is characterized by lower rates of settling and increased erosive capacity. These flows are characterized by an _eddy viscosity_ which is their "apparent viscosity" where n=mew\*10^x and tau=(mew+n)(du/dy)

Question 75

Udden-Wentworth Scale

Answer 75

A geometric scale for measuring grain sizes that uses the rule 2\*(n-1) so each size is two times the prior.

Question 76

Upper flow regime bedforms

Answer 76

planar beds, antidunes, chutes+pools. Steep side towards flow direction. At F_r=1 the buffering of ripples ceases and they are cleaved off to form planar beds. Differentiate upper flow regimes by the erosional shooting traces.

Question 77

Volcanoclastic sandstones

Answer 77

A form of lithic arenites that are pyroclastic material like euhedral spars, pumice, glass, and low qtz.

Question 78

Wackes NEED PIC

Answer 78

Sandstones with grains that are surrounded by mud/silt

Question 79

What does graded bedding indicate in fluvial deposition?

Answer 79

Graded bedding indicates a decelerating flow. The deceleration of flow decreases the size of particles able to be entrained within a flow.

Question 80

What does sorting and roundness represent?

Answer 80

Sorting is representative of the persistence of the energy input or process. Less sorting indicates proximal rocks and good sorting indicates distal sediments where sorting consistently occurs (beaches, dunes...) Roundness accompanies sorting and reflects the transport distance of the grains.

Question 81

What to red rocks indicate?

Answer 81

Red rocks indicate that the iron was in an oxidizing enviroment. Black/green indicate that the iron is reduced to ferric iron and was formed within a anoxic or low oxygen enviroment.

Question 82

Naming mudrocks

Answer 82

1. ) check clay or silt 2. ) Check for laminae or fissility a. ) if laminated then shale or laminated mudstone/siltstone b,) if unlaminated then it is a mudstone/siltstone.

Question 83

Goldich Stability Series

Answer 83

This is the reverse of Bowen's Reaction Series and represents the resistance to weathering.

Question 84

Carbonate Nomenclature

Answer 84

Modifier (optional), Allochem type, allochem abundance

Question 85

Modifiers for Carbonates

Answer 85

Fossiliferous refers to the presence of "bio-clasts" oolitic: indicates a highly agitated, shallow water enviroment intraclasts peloidal: Same as oolitic but without concentricity

Question 86

Ooids

Answer 86

Spherical to ellipsoidal grains .25-2 mm with concentric coating. Nuclei of extra-formational nature. Indicates a high energy, shallow enviroment

Question 87

Pisoids

Answer 87

A small spheroidal particle with concentricity D\>2mm

Question 88

Oncoid

Answer 88

A coated grain of algal or microbial origin that is coarser than 2 mm.

Question 89

Floatstone vs. Rudstone

Answer 89

These terms describe carbonates that have more than 10% of sediments of allochems D\>2mm. Floatstones are matrix supported. Rudstones are grain-supported.

Question 90

Carbonates with an originally solid structure

Answer 90

These are rocks that were autochthenous and are **boundstones** Framestones are composed of a rigid framework like a coral reef Bindstone are composed of binding/encrusting organisms like stromatilites and other algae. Bafflestones are made of organisms that baffled waves/currents

Question 91

Oncoids and Pisoids

Answer 91

Large D\>1 cm concentrically coated that were mobile during formation. Pisoids are not concentric.

Question 92

Chalk

Answer 92

Extremely fine grained light colored lime mud primarily derived from microfossils.

Question 93

Tufa

Answer 93

Highly porous and weakly bedded limestone formed from spring deposits

Question 94

Travertine

Answer 94

Dense, fibrous limestone formed by springs. Often formed with tufas.

Question 95

Nodular soil carbonates

Answer 95

Small irregular lumpy balls of carbonate. May resemble root traces.

Question 96

Coal Types

Answer 96

Anthracite: high grade shiny coal Bituminous or lignite: dull/soft coal Bituminous sands: grey or black sandstones

Question 97

Chert

Answer 97

Microcrystaline silica derived from radiolarian or diatom skeletons. It can also form from volcanic ash.

Question 98

Diatomites vs. Tephra

Answer 98

Diatomites are very homogenous wheras tephra will has heterogeneous glass shards.

Question 99

Evaporites

Answer 99

Chemically precipitated salts like gypsum, anhydrite, halite, sylvite. They infrequently outcrop (weathering) and are banded from variable water inputs.

Question 100

Bedding terminology

Answer 100

Massive: indistinct bedding Very thick = \>1m Thick= .3-1m Med = 10-30cm Thin =3-10 cm very thin = 1-3 cm Laminated = .3-1 cm finely laminated

Question 102

Varves

Answer 102

This is seasonal variation in sediment production, usually annual. It is seen in finely laminated mudstones primarily in lakes.

Question 103

Styolites

Answer 103

Usually formed by the high-pressure dissolution of carbonates along a surface. Appears as rigid zig-zags or teeth.

Question 104

liesegang banding

Answer 104

Concentric and/or ring bands of cements (typically iron stained) that form through groundwater flows. They are more typical in porous sandstones.