364 Geology in the Field Appendix 2 365

APPENDIX 2. Abbreviations of Geologic Terms

Abbreviations for nouns are capita lized to distinguish them from adjecti vcs (see, for example, dolomite and dolomitic). For a more extensive list, sec· M itchell,J.G., and Maher,].C., 1957, Suggested abbreviations for litholog ic descriptions: Bulletin of the American Association of Petroleum Geologists, vol. 41, p. 2103-2107.

abundant abnt clinopyroxene Cpx hypid iomorphic hypid pyritic PY acicular acic cobble Cb! igneous ign pyroxene Px actinolite Act conglomerate Cg! ignimbrite Ignm pyroxenite Pxt aggregate Aggr contact Ctc ilmeni te Ilm pyrrholite Pyrr albite Ab cordierite Cord inclusion Incl quartz Qz amorphous amor corundum Cor interbedded intbdd quartzite Qzl amount Amt cross-bedded xbdd intrusion In tr radiolarian Rad amphibole Amph cross-bedding Xbdg ir regu lar ireg reconnaissance lk con amphibolite Ampht cross-laminated xlam joint Jn t regular reg andalusite Anda! cross section X sect kaolinite Kao! rhyoli te Rhy angle L crystal XI K-feldspar Kspar rocks Rx angular ang crystalline xln laminated lam rounded rncld andesite And diameter Diam limes tone Ls sandstone Ss anhedral anhed different diff limonite Lim saturated sat anhydrite Anhy diopside Diop lithologic lith secondary sec approximate approx disseminated dissem magnet ite Mag sediment Sed arenaceous aren dolomite Doi maximum Max sedimentary secl argillaceous arg dolomitic do! member Mbr serpent ine Spt argillite Arg elevation Elev metamorph ic met s iliceous si l arkosic ark equivalent equiv microli ne Mier s ilts tone Slts t arsenopyrite Ars evaporite Evap montmorillonite Mont soluble sol asphalt ic asph exposure Exp mu clstone Mdst sphalerite Sphal average Ave feldspathic feld muscovi te Muse station Sta bedded bcld foliated fol nephcline Neph staurolite Staur bedding Being foliation Fol nodula r noel structure Struc bentonite Bent foraminifer Foram olivine 0 1 stratigraph ic strat biotite Bio formation Fm orthopyroxene Opx surficial surf bituminous bit fragmenta l frag ort hoclase Orth tabula r tab boulder Blclr glauconite Glauct outcrop Otcp temperature T brachiopocl Brach granite Gr pebble Pb! topographic topo breccia Bx granodiorite Grd pegmatite Peg tourmaline Tourm calcareous calc granular gran per idotite Perid tremolite Trem carbonaceous carb graptolite Grap permeability Perm unconformity Uncf cavernous cav graywacke Gwke phenocryst Pheno variegated vrtg cement Cmt greens tone Grnst phlogopite Phlog vegetation Veg chalcedony Chai gypsiferous gyp phosphatic phos vertebrate Vrtb chalcopyrite Cp hematitic hem plagioclase Plag volcanic vole chlorite Chi horizontal horiz point Pt volu me Vol claystone Cis t hornblende Hbl porphyritic porph wollastonite Woll cleavage Clv hornfels Hfls probable prob xenolit h Xen

372 Geology in the Field

APPENDIX 7: Symbols for Geologic Maps

65 40

2 -------

3 --- ----------

Contact:, showing dip where trace is horizontal. and strike and dip where trace is inclined

Contact, located approximately (give limits)

Contact, located very approximately, or conjectural

4 . ...... . ..... Contact, concealed beneath mapped units

5 =~"=:"=•~·='~~ Contact, gradational (optional symbols)

6 ~ Fault, nonspecific, well located (optional symbols)

7 _::-___:-;::;.:::;,,.-;;::;:: Fault, nonspecific, located approxi mately

8 ::.:-_- _:::,-_ ~ _ ~- Fault, nonspecific, assumed (existence uncertain)

g - • • •• •• • • • • • • • Fault, concealed beneath mapped units

10 ♦-75 ~ ~60

11 ~---~ ~25 32

12 + D 67 13 ♦ R

90 72

14

Fault, high-angle, showing dip (left) and approximate dips

Fault, low-angle, showing approximate dip and strike and dip

Fault. high-angle normal (D or ball and bar on downthrown side)

Fault, reverse (H on upthrown side)

Fault, high-angle st rike-slip (example is left latera l)

15 "'::= • • 36

16 • •

• T- Fault. thrust (T on ovcrthrust side)

• 0......, Fault, low-angle normal or uetachment (I) on dow n thrown side)

17 ........ -..-....--."',..--..- Fau lt, low-angle s trike-slip (example 1s right lateral)

Fault, low-angle, overturned (teeth in direction of dip)

Optional sets of symbols for different age-groups of faul ts

22

23

24

32

Fault zone or shear zone, width lo scale (dip and other accessory symbols may be added)

Faults with arrows showing plunge of rolls, grooves or slickensides

Faull showing bearing and plunge of net slip

Point of inflection (bar) on a high-angle fau lt

~ 4\ • ~ ~ Points of inflection on a strike-slip fau lt passing in to a thrust

25 -----~ 26 ~ • • .,_

27--+-- - 5

28---f l> IO D

80

29 --+--=--t -30 --t-=.-=.-:..-_-_--t--31 ··f·:.-.-.-.-. ·t····· 32 t _t ---,...f -t 33 --fr

u 34 tn 35 t:A

® 36

~~ 37

41 ___ _ .__ _ _

45

42---<L!.__ 43 ~9 }- §-+

44

45 15 15 9

46 -L..... -4:,--o 4--47 -+- -+-

48 EB

Appendix 7

Fau lt intruded by a dike

Faults associated with veins

Anticline, showing trace and plunge of hinge or cn'st li rw (specify)

Syncline (as above), showing dip of axial surface or trough surface

folds (as above), located approximately

Folds, conjectural

Folds beneath mapped units

Asymmetr ic folds with steeper limbs dipping north (optional symbols)

Anticline (top) and syncline, overturned

Antiformal (inverted) syncline

Synformal (inver ted) anticline

Antiform (top) and synform (stratigraphic sequence unknown)

Separate dome (left) and basin

Culmination tldl ) and depression

Small anticline and syncline, showing shapes in horizontal section

Vertically plunging anticline and syncline

Monocline, south-facing, showing traces of axial surfaces

Steeply plunging monoclinc or flexu re, showing trace in horizontal sect ion and plunge of hinges

Plunge of hinge lines of small folds, showing shapes in horizontal section

Strike and dip of beds or bedding

Strike and dip of overturned beds

Strike and dip of beds where stratigraphic tops are known from primary features

Strike and dip of vertical beds or bedding (dot is on s ide known to be stratigraphically the top)

Horizontal beds or bedding (as above)

373

374

49 e 40 ' _,_

50 ~ .1_ ~~

51 ~

52 _!_ 15 ~

15 '---'

53--¢- -+- 1----<

54 + + + 55_£ 1 12

i.....L..i 10 5

---"-- =:=!'!=: 56 _._ ...,._a..,._

-----il.- ~

57 =!= =#== --- •=1

Geology in the Field

Approximate (typically estimated) str ike and dip of beds

Strike of beds exact but dip approximate

Tr_ac~ of single bed, showing dip where trace is horizontal and where 1t 1s inclined

Strike and dip of foliation (optional symbols)

Strike of vertical foliation

Horizontal foliation

Strike and dip of bedding and parallel foliation

Strike and dip of joints (left) and dikes (optional symbols)

Vertica l joints (left) and dikes

58 ~+t +ft Horizontal joints (left) and dikes

59._..t_ __t__

-t2•rr

60-+- 1f.'ff= 61 + q~~r

62

63

64

- 35

:}--- 20

65 ~ 0--66

bio a--;.. --a--+

67 ---<40 ~ 15

68 ~ +-+--

69 ---+-4

70 -:;> ~

-flf-7 ~

Strike and dip of veins (optional symbols)

Vertical veins

Horizontal veins

Bearing (trend) and plunge of lineation

Vertical and horizontal lineations

Hearing and plunge of d cavage-beclding inten;ection

Bear ing and plunge of cleavage-cleavage intersections

Rea,-ings of pebble, minera l, etc. lineations

Bearing of Ii neat ions in plane of foliation

Horizontal lineation in plane of fol iation

Vertical lineation in plane of vertical foliation

Bearing of current from primary features; from upper left: general; from cross-bedding; from flute casts; from imbr ication

71 C > ~

72----j E---7

73 ~

74 ------3

75 C>-., .,___

76 T T

0-- ..... 77 M M

0-.. .......

78 ... 79 BIT

80 X

81 'X'

82 l!l l']-- ~

8'' " >-- )-+-

R4 >--< X

85 • 0 ~

86 • ¾ 87 -<>-

88 Q -6-

89 ¢ -0-

90 0

91 ~ 92 ~111,~ \\\~w, '\. .... .,..

Appendix 7

Bearing of wind direction from dune forms (left ) and cross­bedding

Bearing of ice flow from striations (left) and oricn tat ion of striations

Bearing of ice flow from drumlins

Bearing of ice flow from crag and tail forms

Spring

T hermal spring

Mineral spring

Asphaltic deposit

Bituminous deposit

Sand, gravel, clay, or placer pit

Mine, quarry, or open pit

Shafts : vertical, inclined, and abandoned

Adil, open (left) and inaccessible

Trench (left) and pros pect

Water wells: flowing, nonflowing, and dry

Oil well (left) and gas well

Well dr illed for oil or gas, dry

Wells with shows of oil (left) and gas

Oil or gas well, abandoned (left) and shut in

Drilling well or well locat ion

Glory hole, open pit, or quarry, to scale

Dump or fill, to scale

375

376

APPENDIX 8:

Geology in the Field

Lithologic Patterns for Stratigraphic Columns and Cross Sections

5. Coarse sandstone

9. Graywacke

13. Dolomite­cemented sandstone

17. Shale

2. Clast-supporled conglomerate

3. Matrix-supported conglomerate

6. Fine 7. Feldspathic 8. Tuffaceous sandstone sandstone sandstone

~-ti ~ ~ ~=-:~_:-q 10. Cross-bedded 11. Bedded 12. Calcite-cemented

sandstone sandstone sandstone

~ ~ ~ 14. Silly 15. Sil tstone 16. Mudslone

sandstone

18. Coal bed with carbonaceous shale

19. Pebbiy mudslone

. -

20. Calcareous shale

1'; '111

11111

:

1

11~~~ 21. Limestone 22. Cross-bedded 23. Dolomite

§1:/.1,;1 25. Calcilic dolomite

29. Bedded chert

33. Fossiliferous limestone

37. Crystalline limestone

limestone (dolostone)

~ 11111 26. Sandy 27. Clayey limestone limestone

30. Phosphorite, phosphatic shale

34. Oolitic limestone

38. Micritic limestone

31 Chalk

35. Pelletal limestone

~ 39. Algal dolomite

24. Dolomitic limestone

28. Cherly limestone

36. ln1raclas1ic limestone

~i~~ 40. Limestone conglomerate

ti~~~ 41. Limestone

breccia

45. Rock sail, salty mudstone

49. Coarse granitic rock

Ill 53. Mafic lava

K-¢HJ:,:JS!I> 4 .H, (T .H .!£ l-i

0

tt :c;:l: H:b'. H·~ 57. Hyaloclastite

61. Massive serpentirnte

65. Folded schist

69. Greenstone

73. Foliated marble

Appendix 8

~ 42. Algal dolomite

breccia

t!:::j 46. Peridotite

50. Fine granitic rock

54. Silicic lava

11 II U '1

H II U

58. Tuff

62. Foliated serpentinite

66. Semischistose sandstone

70. Silicic gneiss

74. Foliated calc­silicate rock

43. Gypsum bed, gypsiferous shale

47. Gabbro

51. Porphyritic plutonic rock

)<XXXXX )( X X ~ X

V V V V V

V V

55. Intrusive volcanic rocks

U <f' LI -0, II ~ JI

n c::l Ji Q II 0,

u o "~ u ~ ,r

59. Tuff-breccia

67. Semischistose limestone

71. Mafic gneiss

~ I>~ m--¥1 /\tt/:/: ::;t4=.#.{ .:~~ 77. Quartzite 78. Quartzite 79. Silicic

migmatite

377

~l)_l''f'0J'~] ~/A/ 44. /\11lIyd1IIO, anhy

drilic dolomllo

48. Malic pl11Ionlc 1ock

52. Porphynl1c plutonic rock

56. Pillow lava

60. Volcanic breccia

68. Semischistose gabbro

' .

72. Marble

76. Altcralio1I 7011CS

80. Malic migmalile

' .

378 Geology in the Field

APPENDIX 9: Fossil and Structure Symbols for Columnar Sections and Field Noles*

? Algae ~ Tree trunk fallen

=w Algal mats vol Trilobites

@ Ammonites ~ Vertebrates

'v Belemnites ..- Wood

-v Brachiopods - Beds distinct

y Bryozoans (=) Beds obscure

0 Corals, solitary * Un bedded

ro Corals, colonial Graded beds

lf), Crinoids ~ Planar cross-bedding

* Echinoderms ~ Trough cross-bedding

'° Echinoids ----- Ripple structures

~ Fish bones = Cut and fill

@ Pish scales is Load casts

& foraminifers, general ~ Scour casts

(J) foraminife rs . large ~ Convol ution

(:\ Fossils ~ Slumped beds

~ Fossils abundant 1l1Tr1l' Palcosol

((g) Fossils sparse 'v-'n Mud cracks

~ Gastropods DO□ Salt molds

,! Graptolites c3--0- Burrows

Q Leaves 0 Pellets

@' Ostracodes 0 Oolites

() Pelecypods © Pisolitcs

;;r Root molds <::P<::;? lntraclasts

'r Spicules f'VN, Stylolite

(r;;)I Stromatolites E) Concretion

,.A,- Tree trunk in place $ Calcitic concretion

*Chiefly after· the Standard Lege11d of the Royal Dutch/ Shell Group of Companies (Shell International Petroleum Maatschappij B. V, The Hague. July 1977)

Appendix 10 379

APPENDIX 10: Major Geochronologic and Chronostratigraphic Units in Use by the U.S. Geological Survey1

Eon or Era or Age estimates of Period or System Epoch or Series boundaries in Eonothem Erathem

millions of years2

Quaternary Holocene 0.D10 (Q) -

Pleistocene 2 (1.7- 2.2) -

Cenozoic Neogene Pliocene

5 (4.9- 5.3) -Subperiod or Miocene (Cz) Tertiary

Subsystem (N) 24 (23- 26) -

(T) Paleogene Oligocene 38 (34-38) -

Subperiod or Eocene 55 (54-56) -Subsystem (Pe) Paleocene 63 (63-66) -Cretaceous Late Upper

~ 96 (95-97) -(K) Early Lower 138 (135-141) -Mesozoic Jurassic Late Upper

(Mz) (J) Middle Middle Early Lowe,

205 (200-215) -Triassic Late Upper

(R) Middle Middle Phanerozoic Early l ower

~240 -Permian Late Upper

(P) Early Lower 290 (290-305) -

Pennsylvanian Late Upper Carbon- ( IP) Middle Middle iferous Early Lower

Periods or -330 Systems Mississippian Late Upper

Paleozoic (C) (M) Early Lower

360 (360-365) -(Pl) Devonian Late Upper \

Middle Middle (D) Early Lower 410 (405-415) -Silurian Late Upper

(S) Middle Middle Early Lower

435 (435-440)-Ordovician Late Upper

(0) Middle Middle Early Lower

500 (495-510) -Cambrian Late Upper

(£) Middle Middle Early Lower

~5702 Late Proterozoic• (Z)

900 Proterozoic -.., Middle Proterozoic' (Y) ~ (e) 1600 -.3 Early Proterozoic• (X)

C:

2500 -"' Late Archean• (W) ·;::

3000 .c -E Archean Middle Archean• (V) "' 3400 u (A) -~ Early Archean• (U) Cl. r-- ----·-·--- -- - - - --- - - --- ~ 3800?

pre-Archean (pA)-an informal time term without specific rank. 4550

l. Format modified slight ly from Sohl, N.L., and Wright, W.B. (1980, Changes;,, slmtigm/1it.ir· 1,0111r·11-

cla/u,-e by the U.S. Ceolo1?ical Survey, 1979: U.S. Geological Survey Bulletin 150~-/\, p, /\ 1,/\:!.), with Precambrian units from Harrison, J. E., and Peterman , Z.E. (1980, /\ prclrmrnary proposal for t he Precambrian of t he United States and Mexico: Geological Societyo/Americr, !Jul/1•/i11, v. 91, p. 1128-ll33). See these articles for sources of the origina l data. _

2. Ranges reflect uncertainties of isotopjc and biostratigraphic age assignmcrrn,. /\gcs of bouncl;i ncs not closely bracketed by data shown by ~-

3. A time term w ithout specific rank. 4. Time terms only.