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EARTH 236

Page history last edited by PBworks 17 years, 5 months ago

Paleontology

 

Marks

  • essay 20%
  • labs 40%
    • exam 16%
    • assignments 1.5% x 10 = 15%
    • quizzes 1% x 8 = 8%
    • online quizzes 1%
  • midterm 15%
  • final 25%

 

intro

  • fossil: remains/traces of plants/animals naturally preserved in rock
  • preservation factors: the organism (bigger, harder better), rock lithology (fine grains better; may reflect deposition environment), post-depositional events (destroyed by percolation(diagenesis), metamorphism)
  • fossilization requirements: rapid burial (prevents scavenging, erosion), hard parts
  • types of preservation
    • unaltered soft parts eg amber/permafrost prevents bacteria
    • unaltered hard parts
    • altered hard parts via carbonization (decrease in volatile components), recrystallization, replacement

 

habitats

  • benthic: bottom-dwelling
  • pelagic: in water column
  • planktonic: passively floating
  • nektic: free-swimming
  • sessile: non-mobile

 

  • biostratigraphy: separation and differentiation of rock units based on fossil context
  • paleoecology: study of relationships of fossils to their original environments

 

 

Lab

 

 

lab 1 Microfossils

  • Foraminifera single-cell, protoplasm in test (visually calcareious but some agglutinated (particles "glued" together))
    • one or more chambers divided by septa (with hole=foramen); first is proloculus, last is perifery with aperture
    • chambers: (unibitri)serial+combination, involute/evolute coil, fusiform, flask, coiled uniserial, planispiral, tubular, coiled-biserial, trochoid
    • apertures: dendritic, basal & slit-shaped, circular & terminal, slit-shaped & terminal, sickle-shaped, multiple apertures, sieve-like apertures, pear-shaped, semicircular, bottleneck-like
    • Nummulites and Triticites: huge forams; triticites useful indicators for Pennsylvanian, Permian
  • Radiolaria single-cell, silica test is lacy spehere with delicate spines; become chert
  • Coccollithophores algae secrete calcareious plates (coccoliths) which become chalk
  • Diatoms algae with silicified cell wall (two valves that overlap like pillbox); become diatomaceous earth

 

lab 2

  • phylum Porifera
    • solitary or colonial
    • supports of spicules/spongin
    • (pre?)Cambrian-recent
    • class Calcarea: calcareous spicules
    • class Demospongea: spongin skeleton and/or siliceous spicules
    • class Hexactinellida: siliceous spicules
    • class Stromatoporoidea: calcarious sheet/cabbage-like structure; common in Silurian, Devonian; sometimes put into Demospongea
  • phylum Bryozoa/Ectoprocta
    • colonian zoarium of zooeciums that each hold a zooid
    • aperture = autopore; monticule = bump
    • Ordovician-recent
  • Archaeocyantha (Cambrian)
    • probably a sponge, but usually have inner and outer wall with septa between
  • Receptaculites (Ordovician to Devonian, maybe Permian)
    • pores (pillars in cross-section) in gentle spirals
    • maybe a calcareous algae
  • Conularia (Cambrian-Triassic)
    • probably a cnidarian
    • longish 4-sided shape (wider at one end) with herringbone pattern

 

lab 3 Cnidaria (Coelenterata)

  • phylum Cnideria > class Anthozoa > subclass Zoantharia = corals
  • cnidarians are polyps (tentacles around mouth/anus) or medusae
    • have cnidocysts or whatever
  • coral is polyp inside cup-shaped theca (usually CaCO3, usually divided into segments by radial septa)
  • as they grow, deposit tabulae (horizontal floors)
  • solitary or colonial (corallum made up of corallites)
  • marine
  • sessile
  • order Rugosa: 4-fold septa, solitary/colonial
  • order Tabulata: no/poorly-developed septa, have tabulae, only colonial
    • suborder Favositina, family Favosites: honeycomb
    • suborder Halysitina, family Halysites: chainish
    • suborder Syringoporina, famiily Syringopora: organ pipes
  • order Scleractinia: 6-fold septa, colonial/solitary, low density
  • age: Rugosa/Tabulata Cambrian?, Ordovician-Permian, Triassic?, Scleractinia Triassic-recent
  • coral forms
    • colonial
      • ceriod: walls with polygonal outlines (honeycomb)
      • astraeoid: no epithecal walls between individuals (their septa are joined)
      • coenosteoid: colonial skeleton between individuals
      • fasciculate: separated individuals; dendroid (branching) or phaceloid (parellelish)
      • cateniform: elongated corallites joined at narrow ends (chain)
      • meandroid: duh (brain coral)
    • solitary
      • ceratoid: elongated horn
      • cylindrical: parallel edges
      • scolecoid: crooked/twisted
      • trochoid: shortened horn
      • patellate: short cone
      • discoid: like a puck

 

lab 4 Brachiopoda

  • Cabrian-recent
  • marine, benthic
  • bilaterally symmetrical
  • brachial valve and pedicle valve
  • inarticulates (chitin) and articulates (hing, sometimes with teeth and sockets)
  • growth lines, sometimes radial lines (ornamentation/strength)
  • subphylum Rhynchonelliformea
    • order Strophomenida concavo/plano-convex, long strophic hing, pseudopunctate, Ordovician-Carboniferous
    • order Productida plano/concavo-convex with deep body cavity (often spiny, sometimes bizarre), strophic hinge, Devonian-Permian, ?Triassic
    • order Orthida unequally biconvex (or plano-convex), usually impunctate, strophic hinge, usually ribbed, Cambrian-Permian
    • order Pentamerida biconvex, impunctate, normally non-strophic hinge, spongydllium (->opening), Cambrian-Devonian, sorta 5-sided
    • order Rhynchonellida biconvex, non-strophic hinge, coarse ribs with zigzag comissure and prounounced fold & sulcus, normalliy impunctate, Ordovician-recent
    • order Atrypida biconvex, short/non-strophic hinge, impunctate, spiral brachidium, Ordovician-Devonian
    • order Spiriferida "wings", biconvex, long strophic hinge, ribbed with interareas, Ordovician-Jurassic
    • order Terebratulida "lamp", biconvex, short non-strophic hinge, endopunctate, umbronal foramen, Devonian-recent
  • subphylum Linguliformea no teeth/sockets, mantle andmuscles hold valves together, chitonophosphatic, Cambrian-recent
    • order Lingulida "padde", low umbo, many fine growth lines, straight comissure

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