Geology

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Geology (地質学)

Mount Usu / Sarobetsu post-mined peatland
From left: Crater basin in 1986 and 2006. Cottongrass / Daylily

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an earth science concerned with the solid earth, the rocks of which it is composed and the processes by which they change over time

mineralogy (鉱物学)
lithology (岩石学)
stratigraphy (層序学) - historical geology (地史学)
palaeontology (古生物学) - geological timescale

Ground structure (大地構造)

Mobile belt (変動帯)/orogenic belt (造山帯)
Orogenic movement (造山運動)
Geosyncline (地向斜)

an obsolete geological concept to explain orogens (developed in the late 19th and early 20th c.) before the plate tectonics theory was envisaged

VLBI, very long baseline interferometer (超長基線電波干渉法)

the measurements of plate movement direction and speed

GPS, global positioning system

Ex. Pacific plate: moving to Japan Islands at 10 cm/yr

Marine geology (海洋地学)

Heat flow measurement (地殻熱流量測定)

1947 Peterson on the Albatross: first try to measure heat flow
1952 Ravelle & Maxwell: success in heat flow measurement

1944 Bullard, Revelle and Maxwell: developed the apparatus
1950 data collected by Scripps Institution of Oceanography

Heat Flow, Q = K·ΔT/ΔD

T = thermal conductivity, measured by difference of temperature between two depths (in the field)
D = thermal gradient, measured using the rock samples

Prior to proposed continental drift hypothesis by Wegener 1596 Ortelius, Abraham (1527-1598)
1756 Lilienthal, Theodor Christoph
1801/1845 von Humboldt, Alexander (1769-1859)
1858 Snider-Pellegrini, Antonio

the shapes of continents on opposite sides of the Atlantic Ocean fit together

Wegener, Alfred (1880-1930, Germany)

1912 proposed continental drift hypothesis (大陸漂移説)

Hess, Harry Hammond (1906-1969)
Dietz, Robert Sinclair (1914-1995)
Blackett, Patrick Maynard Stuart (1897-1974, England), paleomagnetism

1947 a theory to account for the Earth magnetic field

as a function of its rotation, trying to unify the electromagnetic force and the force of gravity - rejected by himself

1948 Nobel Prize (physics) by cloud chamber, positron and its pair

Dynamo theory (ダイナモ理論)
Larmor, Sir Joseph (1857-1942), England

1919 a mechanism that sun generates a magnetic field

core in earth = liquid iron → dynamo

Seafloor spreading (海洋底拡大説)
Hess, Harry Hammond (1906-1969), American geologist
1962 (1960 pre-print) Hess: geopoetry

Nature of great oceanic ridges. The 1st International Oceanographic Congress (New York, August 31-September 12 1959). Washington. American Association for the Advancement of Science (A). pp. 33–34

Dietz, Robert Sinclair (1914-1995), American marine geologist
1961 Dietz RS: proposed seafloor spreading

Continent and ocean basin evolution by spreading of the sea floor. Nature 190: 854–857

Vine, Frederick John (1939-), English marine geologist
Matthews, Drummond Hoyle (1931-1977), British marine geologist
1963 Vine & Matthews (Nature 199: 947–949)

developed to Vine-Matthews-Morley hypothesis (VMM)

reversed polarity (+ ↔ -) + spreading seafloor at mid-ocean ridge

Wilson, John Tuzo (1908-1993), Canadian geologist
1965 proposed transform fault or boundary (トランスフォーム断層)

a major plate boundary where two plates move past each other horizontally

1966 (and thereafter) Cox and others tape recorder model

Earth magnetic polarity reversals in last 5 million years. Dark regions represent normal polarity, i.e., same as present field; light regions represent reversed polarity.

JOIDES (Joint Oceanographic Institutions Deep Earth Sampling)

1968-1983 Ship Glomar Challenger
1985- Ship JOIDES Resolution (JR)

Theory of plate tectonics (プレートテクトニクス)

= lithosphere comprises a number of large tectonic plates that have been moving a few centimeters per year
Def. (tectonic) plate: composed of the oceanic lithosphere and the thicker continental lithosphere, relatively rigid and floats across the ductile asthenosphere beneath

Three types plate boundaries

Divergent (発散型): pulling apart from each other
Convergent (収束型): pushing boundaries together
Transform or conservative (平行型): sliding across from each other

Fig. Distribution of major tectonic plates on the earth

Stratigraphy (層序学/層位学)

a branch of geology concerned with the study of rock layers (strata) and layering (stratification)
Table. Geological timescale, based on Family Waagenophyllidae (Kanmera 1973, 勘米良亀齢)
Era_______Fusulinida band (フズリナ属帯)
Triassic

Lower: -

Permian

Upper: Palaeofusulina, Codonofusiella
Middle: Yabeina, Neoschwagerina, Cancellina
Lower: Misellina, Pseudofusulina, Pseudowagerina

Carboniferous

Upper: Triticites
Middle: Fusulina-Fusulinella

Fig. 1.76. Morphology of Fusulinidae (紡錘虫). (a) Fusulinella. (b) Yabeina. A-A': axis of coiling, pr: proloculus, spi: spirotheca, s: septa, sp: septal pores, sf: septal fluting, c: chomata, t: tunnel, ef: external furrow, pts: primary transverse septula, sts: secondary transverse septula, as: axial septula, a: antetheca, pc: parachomata, f: foramina, lp: lateral passage. (Modified after Maklukho-Maclay et al. 1959).

Fig. 3.9. Interrelationships of life habits within the marine ecosystem.

Habitat: Feeding type
Planktonic:
Herbivores = Gastropods (Pteropods)
Nektonic:
Filter feeders = Pelecypods (Scallops)
Carnivores/Scavengers = Belemnoids, Nautiloids, Ammonoids, Trilobites, Echinoids
Vagrant benthonic:
Filter feeders = Trilobites
Herbivores = Gastropods, Echinoids
Carnivores/Scavengers = Gastropods, Nautiloids, Ammonoids, Trilobites, Echinoids
Sessile benthonic epifauna (and epiphyta):
Autotrphs = Algal stromatolites, Calcareous algae
Filter feeders = Corals, Tabulates, Stromatoporoids, Sponges, Bryozoans, Brachiopods, Pelecypods, Crinoids, Blastoids
Carnivores/Scavengers = Corals
Benthonic infauna:
Filter feeders = Pelecypods, Brachiopods
Sediment feeders: Pelecypods, Echinoids
Carnivores/Scavengers = Gastropods, Trilobites

Fig. 5.34. Carboniferous coral zones and brachiopod/coral subzones, British Isles (Stamp 1950). An introduction to stratigraphy British Isles. Subzones: K₁: Productus basus, K₂: Spiriterina octoplicata, Z1: Spirifer tornacensis, Z₂: Zaphrenus konincki, C₁: Caninia cylindrea, C₂: Palaeosmilia φ, S₁: Caninia bristolensis, S₂: Productus corrugato-hemisphericus, D₁: Dibunophyllum bourtonense, D₂: Lonsdaleia floriformis. (Yaughan 1905)

Mineralogy (鉱物学)

Rock (岩石・岩)

Table. Major minerals that form volcanic rocks. The chemical equiations are simplified. All the minerals except silica minerals forms various degrees of solid dispersion.
colorless mineral (無色鉱物)

plagioclase (斜長石)

CaAlsSi₂O₈ (anorthite 灰長石), An _{[→ abbreviation of terminal component]}
NAAlSi₃O₈ (albite 曹長石), Ab

potassium feldspar (カリ長石)

KalSi3O8, Or

feldspathoid (準長石)

NaAlSiO4 (nephelite 霞石), Ne
KalSi2O6 (leucite 白榴石), Lc

silica minerals (珪酸鉱物)

SiO2 (quartz 石英・tridymite 鱗珪石・cristobalite 方珪石)

Colored mineral (有色鉱物)

peridotite (橄欖岩)

(Mg, Fe)2SiO4

pyroxene (輝石)

(Mg, Fe)SiO3 (orthopyroxene 斜方輝石)
(Ca, Mg, Fe)SiO3 (clinopyroxene 単斜輝石)

amphibole (角内石)

(Ca, Mg, Fe, Na, Al)7-8[(Al, Si)4O11]2(OH)2

biotite (黒雲母)

K(Mg, Fe)3[(AlSi3)O10](OH)2

magnetite (磁鉱鉱)

Fe²⁺, Fe³⁺2O4 (incluidng a small amount of Ti, Mn, etc.)

volcanic glass (火山ガラス)

silicate glass containing Mg, Fe, Ca, Na, K, Al, etc.

lava (溶岩)

Lithology (petrology, 岩石学)

rock = igneous rocks + sedimentary rock + metamorphic rock

Igneous rock (magmatic rock, 火成岩)

formed through the cooling and solidification of magma or lava
= intrusive rock (貫入岩) + extrusive rock (噴出岩)
Intrusive rock: formed when magma penetrates existing rock, crystallizes, and solidifies underground to form intrusions
Extrusive rock: derived from magma that was poured out or ejected at the earth surface

Granite (花崗岩)

coarse-grained (phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase

Metamorphic rock (変成岩)

formed by metamorphism (the transformation of existing rock to new types of rock)

Ex. phyllite (千枚岩), schist (片岩), gneiss (片麻岩), quartzite (珪岩) and marble (大理石)

Serpentine belt (蛇紋岩帯)

Serpentine (蛇紋岩)

A rock composed of one or more serpentine group minerals

Serpentine group minerals

Minerals in this group are formed by serpentinization, a hydration and metamorphic transformation of ultramafic rock from mantle.

Serpentine soil

low Ca/Mg ratio
lack of essential nutrients, N, K and P
ultramafic, due to heavy metals

Plants in serpentine belts

Serpentine zone supports diverse wildflowers that are occasionally rare or endangered species, such as Primula takedana and Berberis amurensis var. japonica.
Species sepcifically established in serpentine zones can be used as ecological indicator Plants in the serpentine zone of Teshio, northern Hokkaido
Achillea ptarmica L.

var. macrocephala (Rupr.) Ohwi (エゾノコギリソウ)
var. yezoensis Kitamura (ホソバエゾノコギリソウ*)

Aconitum yezoense (エゾトリカブト)

Allium schoenoprasum L. var. schoenoprasum (エゾネギ)
Berberis amurensis Rupr. var. japonica (Regel) Rehd. (ヒロバノヘビノボラズ*)
Clematis fusca Turcz. (クロバナハンショウヅル)
Drosera rotundifolia (モウセンゴケ)
Euphorbia sieboldiana Morr. et Decne. (ナツトウダイ)

var. montana Tatew. (ヒメナツトウダイ*), syn. E. tsukamotoi Honda

Galium verum L. var. trachycarpum DC. (エゾノカワラマツバ)
Japonolirion osense Nakai (テシオソウ)
Picea glehnii Masters (アカエゾマツ*)
Pinus pumila (ハイマツ)
Primura takedana Tatew. (テシオコザクラ*)
Primura takedana
Sanguisorba tenuifolia var. alba (ナガボノシロワレモコウ)
Swertia tetrapetala (チシマセンブリ): highly variable (small in the observed area)
Thymus quinquecostatus Celak. (イブキジャコウソウ*)
Veronica schmidtiana

ssp. senanensis Kitam. et Miura var. yesoalpina (エゾミヤマクワガタ)
ssp. schmidtiana (キクバクワガタ), dull on the top of calyx, in Hokkaido

*: observed often in the serpentine belt of Teshio
[ Field training on integrated environmental research ]

Sedimentary rock (堆積岩)

Three processes: sedimentation = weathering + migration + deposition
Regolith (レゴリス): a blanket of unconsolidated, loose, heterogeneous superficial deposits covering solid rock, e.g.,

pedolith (ぺドリス) ≈ soil: a surface formation that has undergone one or more pedogenic processes
alluvium (沖積層) (and other transported cover)
saprolith

upper saprolite: completely oxidized bedrock
lower saprolite: chemically reduced partially weathered rocks
saprock: fractured bedrock with weathering restricted to fracture margins

tephra and lava (火山噴出物)
duricrust (表面固化物): formed by cementation of soils
groundwater
biota and the organic components

Limestone (石灰岩): CaCO₃, a white or light grey rock formed from the shells of sea animals