EAS 207 Final

K- Kreide, Cretaceous Period. P- Palaeogene Period

K-P

Black Clay Shale Layers, thin smectite-illite-kaolinite clay units identify boundary between Mesozoic and Cenozoic, radiometric dating at 66 ± 0.011 mya, changes in fossil distribution

Physical Indicators of K-P Boundary

67% of species went extinct, >60% foraminifera, sponges, brachiopods and mollusks extinct. 100% extinct for non-avian dinos, large marine reptiles, pterosaurs, invertebrate ammonites, beleminites, bivalves. Short term collapse of phyto- and zooplankton in oceanic photic zone, fall of carbonate biproductivity and primary productivity. However no major loss of reefs and corals, invertebrates transition and change

What Went Extinct During K-P

Chixculub Meteorite Impact, Indian Deccan traps (started many years before K-P), Orogenic events, climate and sea level changes (plate tectonics), global volcanism in late Maastrchtian, around 66mya

End Cretaceous Events

In Western India, massive flood basalts, 2000m thick, erosion over 66my lost 3x amount

K-P Deccan Traps

Hot at the end of Cretaceous, then became cool, earth split and starting to look like present day but Australia was still connected to Antarctica

K-P Climate Change

70 - 40mya, 5 major accretion tectonics, uplift and thrusting

Laramide Orogeny

90 - 30 mya, large number of accretion tectonics, uplift and thrusting

Andean Orogeny

1. Iridium, plutonium isotope concentration

2. Microtektites - melted silicate from heat of impact

3. Shocked fractured quartz from high pressure and impact

4. Gravity Anomalies - dense concentration of matter in crust that increase gravitational field

Physical Indicatiors of Extra Terrestrial Impact

Predicted meteorite in K-P extinction, but no crater found

Alvarez

Defined biostratigraphically in 1964 using planktonic foraminifera in Gubbio Italy

K-P boundary first detected

Clay divisions that show boundary. Silt, sand and bentic clay found at the bottom. Sandy bentonite volcanic ash found in boundary clay. And Carboniferous clay and coal at the top

RTMP K-P Specimen

In Yucatan Peninsula Mexico K-P, impact site found by Alan Hildebrand in 1990s, huge crater (100km), now covered by sediment, has all 4 meteorite evidence, remains of Carboniferous chondrite of a asteroid, surrounded by a ring of cenotes (upper paleozoic limestone and karst, erosion in Carboniferous rock), gravity waves, tectonic plate offset

Chixculub Impact

Unknown if it alone caused extinction, but K-P only extinction with definite effects. Atmospheric dust for decades, extreme heat, cataclysmic earthquakes, volcanism, collapsed carbon cycle and food chains. Plants survived and some ecosystems didn’t collapse

Chixculub Impact Over Time

2my before K-P boundary

Mesosaur Extinction

Only large extinction event in the Cenozoic, smaller events have large scaled climate change, grasses take over, new things evolve

Eocene-Oligocene Extinction Event

Large scale plants and animals, mostly marine, cetaceans, large primary consumer losss because shrubs and berries replaced with grass

Eocene-Oligocene Extinctions

Part of Eocene-Oligocene Events. “Great Break” linked Oi-1 Glaciation. Two phase large scale turnover in terrestrial floral and fauna, France, England, Germany, found by George Cuvier

Grand Coupure 1 and 2

Large scale climate cooling, major global sea level drop, increased aridity, vegetation changes, onset of polar glaciations, no volcanisms, tried to link to bolide Chesapeake Bay, Popigai, Toms Canyon

Eocene-Oligocene Causes

Part of the Paleogene Period, 66-56mya

Palaeocene Epoch

Lots of trees, rising sea basin, no grasslands or savannas, NA created and destroyed a seaway, western interior sea gone, Deccan traps, very warm

Palaeocene - Eocene Climate

66mya, climate was tropical, poles did not have any ice, forested or open brush land, grass just evolved, 24-25 degrees, start of primitive whales, fish explosive radiation, marine reptiles lost, Eocene had earliest leatherback sea turtle, cheloniids radiated

Paleocene

Modern sea turtles, evolved in late Cretaceous

Cheloniids

Leatherback sea turtle, evolved in middle Eocene

Dermatochelid

Paleocene - Eocene Thermal Maximum, 55.5mya, 5 degree raise in temperature for a long time, prolonged massive carbon release into the atmosphere, linked to volcanism and North Atlantic Igneous Province, forms Thulean Plateau in Palaeocene then breaks apart when North Atlantic opens, temperature decreases

PETM

Basaltic Spew, includes Iceland, and Rockall Plateau, soft weathered rock, flood basalts

North Atlantic Igneous Province

Loss of biomass from 30-40% loss of benthic foraminiferans, mammals migrate to terrestrial environments because of warming, 13000 years after PETM, loss of marine organisms, bottom of food chain had a loss which affect everything else (downstream effect), metabolic loss because of warming because organisms now need to be active all year

Palaeocene - Eocene Extinctions

Single called amoeboid protist, ectoplasm wall to catch food, shell made of chitin or calcium carbonate, few planktic, live in sediment, large biomass, many photosynthetic or heterotrophs, cause carbon sinks and negative carbon excursion reflect

Foraminiferan

40% of foraminifera loss (evidence from negative carbon excursion, carbonate disappears, only clay deposited no chemical carbonate rocks loss of calcium carbonate, loss of planktic dinoflagellate

PETM Extinctions

Evolved in Early Eocene because earlier there was an unstable food web as a result from PETM and NAIP basaltic volcanism

Secondarily Aquatic Tetrapods

Early Eocene Climatic Optimum (53-51mya), warmest global temps in the Cenozoic, 14 degrees warmer than pre-industrial period, 5 degrees warmer than late Eocene

EECO

Eocene Thermal Maximum occurred 3my after PETM

ETM

In Eocene-Oligocene but no cause-effect to meteorite impacts

Foraminiferal Turnover

35.5mya well before Eocene-Oligocene Extinction, near Appalachian Mountains

Chesapeake Bay Impact Site

The great break, Eocene-Oligocene Extinction event, Europe, 33.9mya, two phase extinction and faunal turnover event recorded in European mammals and flora

Phase 1 - European mammal extinction

Phase 2 - Asian mammal immigrations, invasion spread across the world

Grand Coupure

1 - Perissodactyla (early horses) - †Palaeotheriidae

2 - Artiodactyla (cloven-hoofed mammals) - †Anoplotheriidae, †Xiphodontidae, †Choeropotamidae, †Cebochoeridae, †Dichobunidae and †Amphimerycidae (deer, cows, moose)

3 - Rodentia - †Pseudosciuridae

4 - Early Primates - †Omomyidae, †Adapidae

5 - Archontans - †Nyctitheriidae (Archonta is a clade that includes primates, insectivores, dermopterans, etc...and sometimes bats) (hedgehogs, lemur)

Pre-Grande Coupure Mammals that go Extinct

1 - Marsupial - †Herpetotheriidae,

2 - Artiodactyla – †Cainotheriidae (extinct today)

3 – Rodentia - †Theridomyidae and Gliridae (big group that includes rodents and lagomorphs, bunnies)

Pre-Grande Coupure Mammals that Survive

1-True rhinos - Rhinocerotidae

2 - Artiodactyla – †Entelodontidae (ancient pig clade), †Anthracotheriidae (sistergroup to hippos) and †Gelocidae

3 - Asian rodentia -† Eomyidae, Cricetidae (hamsters) and Castoridae (beavers)

4 – Insectivores - Erinaceidae (hedgehogs)

Post-Grande Coupure Asian Immigrants

18-14mya Early Miocene also called Miocene Climatic Optimum, ice melts, long cooling with warming phase, grasslands, water disappears because of freezing

Miocene Epoch

14mya, Langhian Stage, Regional to general extinctions of terrestrial and aquatic life forms in higher latitude environments, global cooling, formation of ice sheets in polar environments, growth of EAIS

Middle Miocene Disruption

East Antarctic Ice Sheet

EAIS

changes in oceanic circulation, decreased CO2 levels, organic carbon fixation, leads to EAIS, theory of Milankovitch Cycling

Middle Miocene Disruption Cause

changes to earth orbital plane ‘obliquity’ (plane of orbit), and ‘precession’ (angle of axis of rotation)

Milankovitch Cycling

Late Miocene, 5.96-5.33mya, partial to complete drying up to Mediterranean Sea (saltier than complete), several cycles, tectonic activity over Gibraltar and forms above sea level barrier, 3-5km deep dry basin, evaporating water raised sea levels by 12km, enormous salt and other evaporite deposits, global ocean reduced salinity, raised freezing point and sea iced formed

Messinian Salinity Crisis

Camarinal Sill breach, 5.33mya, waterfall of Atlantic seawater filling the Mediterranean Basin would, elephant prints found at bottom of basin, huge waterfalls but evaporate when reach sea

Zanclean Flood

Anything living in Mediterranean gone extinct, Terrestrial organisms migrated back and forth across the basin, floras and faunas able to survive in increasingly dry and cool climates because of global climate change

Effect of Messinian Salinity Crisis

cats, dogs, (crown carnivores) raccoons, coatamundis, bandicoots pandas, bears, mongooses, weasels (big group), hyaenas.

Carnivora

Oldest carnivores, predatory, flesh-eating, parietal/sagital crest back of head to get stronger bite, acute sensory systems, dentition modified for killing & slicing flesh, enlarged canines, post-canines: Premolars and molars, carnassial pair

Pan-Carnivora

Cats, Hyaenas, Moongooses, Civets

FELIFORMIA

Dogs, Bears, Weasels, Raccoons

CANIFORMIA

P4, M1 4th premolar and 1st molar

Carnassial pair in Pan-Carnivora

Early carnivores in early Paleogene that has no carnassial pair and shears on all molars but especially M1/M2 or M2/M3, and has a smaller brain, not monophyletic, late Cretaceous/Palaeogene to Miocene/Pliocene, moved from NA to Europe but evolved in Africa

Creodonta

cursorial, pursuit Predators, plantigrade to digitigrade, reduced clavicle to help with running, prey co-evolution

Mammalian Carnivores Characteristics

Longer stiffer arms, walk on toes, run longer and faster, better than plantigrade

Digitigrade

Carnivorous Mammals and prey co-evolved, prey get grazing teeth and both evolved to run faster with longer legs and decreased clavicles because of grass exposure. Running really fast just to stay in one place

Red Queen Hypothesis

Part of creodonta, mid Paleogene, resembles hyaena dentition that is bone crushing but not related to hyaenas, Oligo USA, digitigrade, long skulls, parietal/sagital crest back of head to get stronger bite. Ex. Apataelurus, Simbakubwa kutokaafrika

Hyaenodonta

Hyaenodonta, early Eocene, Eurasia, carnassial pair comparable to that of felids, sabertooth canine

Apataelurus

Hyaenodonta, early Miocene, Kenya

Simbakubwa kutokaafrika

Creodonta, NA, Mid Paleocene - Late Eocene, plantigrade, short broad skulls, converge on cats, crushing dentition, occlusion, slower than Hyaenodonta,

Oxyaneodonta

Viverravidae – Middle Palaeocene->Eocene, Miacidae – Late Paleocene ->Eocene

Oldest Carnivores

Canidae (Early Oligocene->Recent)

Ursidae (Pleistocene->Recent)

Procyonidae (raccoons, pandas, red panda, kinkajoo, cotamundi)

Mustelidae Poor fossil record

Caniformia Lineages

Viveriidae – Eocene to Recent

Herpestidae – Eocene to Recent

Hyaenidae – Miocene to Recent

Felidae - Early Oligocene to Recent

†Nimraviidae (false cats) Mid Eocene Late Miocene

Feliformia Lineages

Canidae, Caniformia, digitigrade, small, like a fox, primitive carnivorans, 5 toes on front, 4 rear, claws not retractile, tail long, stiff back, cursorial, reduced clavicle

Hesperocyon

Canidae, Pleistocene, “Direwolf”

Canis dirus

Canidae, bigger than grey wolf, big parietal crest, robust, crushing, high bulbous forehead, Miocene - Pleistocene, hyaena-like niche in N. Amer. only

Borophaginae

Feliformia, modern forms, Miocene to Recent, good vision compared to canids, sharp, retractable claws, long tail, long body dentition for shearing, jaws swing in vertical plane (no side to side like deer), shearing is vertical, no lateral movement (no crushing/grinding), canines, pierce; carnassials shear; drop lower jaw, gape emphasized

Felidae

North American Lion, Felidae, larger than lion; extinct by end of Pleistocene, might not be lion but more similar to tiger or jaguar

Panthera atrox

True cat, saber-toothed, Felidae, Pleistocene form, La Brea Tar pits, SA, Eurasia, NA. Recurved, laterally compressed, serrated canines, pinnacle of stab and shear (important to group), Carnassials enormous, no more teeth at back of mouth because no grinding

Smilodon

informal taxon, “hoofed mammals.” Hooves lacking in some primitive forms and lost in some derived forms, i.e., cetaceans. Mostly herbivores, bunodonty dental trend

Ungulates

molars and premolars become roughly rectangular, develop crest systems, for grinding and chewing because grass and silica hard on teeth

Bunodonty

1 w-shaped crest in molars ex. Horse, rhinos

Lophodont

2 w-shaped crests in molars, ex. Deer, moose

Selenodont

Decreased tooth crown height, primative

Brachyodont

Increased tooth crown height, high crested, deeply rooted, derived, evolved in Miocene for grazing

Hypsodont

Loss of canines, specialized incisors for cropping (plucking plants out of the ground), lost upper incisors, big diastema (gap between jaws), deep jaws for deep tooth roots, increased skull length, jaw musculature shifts side to side movement of lower jaw

Ungulate Skull

Body stiffer; adaptations for cursoriality, forearm bones fuse, short femur, long ankle bone, upper limb bones shorter than lower limb components, loss of clavicle, digitgrade stance to unguligrade (tips of terminal unguals), reduction in number of toes

Ungulate Body

In Ungulates, digestive tracts evolve in concert with flattened grinding teeth evolve bacterial fermentation ‘sacs’. Perissodactyls - hindgut, artiodactyls - fore and hindgut, to get enough nutrients because grass does not have much

RUMINANTS

Modern Ungulates, cetaceans, Perissodactyla, Artiodactyla

Laurasiatheria

mesaxonic, middle digit form axis of foot (walk on one toe), emphasis on 3rd toe, lost 1 and 5, ex. horses, zebras, rhinos, tapirs

Perissodactyla

Odd toed

Mesaxonic

Paraxonic, parallel limbo bone split of 2 toes, emphasis on 3 & 4, ex. Whales, camels, pigs, cervids (giraffes, deer, oxen and antelopes, pronghorn), Hippos, Cetaceans

Artiodactyla

Even toed

Paraxonic

Condylarths, Mesonychids, Dinoceratids,

Ungulate Waste Bucket Taxon

Meridiungulata – Pyrotheria, Xenungulata, Astrapotheria, Notoungulata and Litopterna, thought to have originated in SA from NA. Condylarth ancestor. Arguments made that Pyrotheria are Afrotherians (Eocene Interchange with Africa via Antarctica)

Other Ungulate Lineages

Phenacodontidae, Palaeocene, ancestors of perissodactyls, dentition, perissodactyl-like, cusps linked by crests, not selenodont pattern Ectosion, similar tooth structure to Hyracotherium

Phenacodus

Arctocyonidae (Cret - Pal)

Protoungulatum (Late Cret. - Sask.), size of a house cat, large for Cret. Placentals, Still have primitive tribosphenic molar

Waste Basket Taxon Examples (CONDYLARTHS)

Early Eocene to now,

Hippomorpha - Equoidea (horse), Brontotherioidea (titanotheres), Chalicotherioidea

Ceratomorpha - Tapiroidea, Rhinoceratoidea

PERISSODACTYLA

Giant sized pigs, Late Eocene to Middle Miocene

Hell Pigs, Entelodonts

Complex, many extinctions in Pliocene, single modern genus Equus

Horse Phylogeny

First Fossil Horse, North America, Early Eocene 52 mya, small, cat sized (large in later horses), four toes in front (2-5), 3 in back (2-3-4) = 3rd largest in both -> reduced to 3rd, metatarsals and toes start to fuse, grazing, bachyodont teeth, pm's molarize, diastema, found green river shale Wyoming, long digits

Hyracotherium (=Eohippus)

Early Eocene – Oligocene Extinction event, Equid relative, but not considered ancestral to modern horses, Eocene Messel Pit, Frankfurt, with baby preserved inside the mothers body cavity

Propalaeotherium

Modern horse, evolved in Pleistocene, toes fully fused, hypsdonty teeth

Equus

Late Eocene, horse relative, 5th digit very tiny almost fused, brachydonty teeth

Mesohippus

Mid Miocene Horse ancestor, 5th digit fully fused but still have 2, 3 and 4, start of hypsdonty teeth

Merychippus

Late Miocene, horse ancestor, digits 2 and 4 very tiny, fully fused to 3, hypsdonty teeth

Pliohippus

Whales, closest ancestor is hippos and linked to Suinae (pigs)

and mesonychids

Cetancodontamorpha

Primitive artiodactyls, Basalmost members of Cetaceamorpha, ex. Diacodexis - Early Eocene (55- 46mya) Global distribution, Helohyus- Early Eocene (50-32mya), looks like a very tiny deer

Dichobunidae & Helohyidae

artiodactyl, Early Eocene (48mya), Kashmir, Pakistan, Possesses cetacean feature of the involucrum, secondary aquatic adaptations, pachyostosis of limb bones for buoyancy control, low crown crushing dentition, browser, ears similarity to whales ex. Indohyus

Raoellidae

bone growth mode which produces a characteristic

bulla of bone over the middle ear ossicles

Involucrum

Early Eocene (48mya), Kashmir, Pakistan, ex. Himalayacetus subathuensis, Ambulocetus natans

Ambulocetidae