Founders of Historical Geology

Can be traced back to classical Greece

Nicolaus Steno (Neils Stensen) 1638-1687

Originally a Danish physicianAn expert in anatomy

(Public Dissections)Developed the fundamental

principles of historicalgeology

Physician to the de Medicifamily in Florence

Nicolaus Steno (Neils Stensen) 1638-1687

In 1669, Steno wrote De solido intra solidum naturaliter

contento dissertationis prodromusProdromus to a dissertation on Solids

Naturally Enclosed in Solidsonly 78 pages long

Founders of Historical Geology

Founders of Historical Geology

Superposition - The scientific law stating that in any unaltered sequence of rock strata, each stratum is younger than the one beneath it and older than the one above it, so that the youngest stratum will be at the top of the sequence and the oldest at the bottom.

Founders of Historical Geology

Superposition, con’t.

With tilted beds, we needto consider othersedimentarystructures, like ripple marks,mudcracks,graded bedding, geopetal structuresor cross-bedding to help determineup direction.

Can also use vesicles inlava flows.

Founders of Historical Geology

Principle of Original Horizontality - The scientific law stating that sediments settling out of a fluid (air and water) are deposited horizontally or nearly horizontally in layers that lie parallel or nearly parallel to the Earth’s surface.

Founders of Historical Geology

Principle of Lateral Continuity - The scientific law stating thatas originally deposited, strata extend in all directions until theyterminate by thinning at the margins of the basin, endabruptly against some former barrier to deposition, or gradelaterally into a different kind of sediment.

Founders of Historical Geology

John Strachey 1671-1743

Used superposition and original lateral continuityDetermined the stratigraphic succession of coals in EnglandRecognized what would later be termed unconformities

Performed local-scale observations.

Founders of Historical Geology

Giovanni Arduino 1714-1795

Had a broader global view of sedimentary layersDeveloped the first classification of rocks and relative ages

Primary Mountains crystalline rocksoldest rocks on Earthlater became igneous/metamorph.

Secondary Mountains layeredfossiliferous rockslater sedimentary rocks

Tertiary unconsolidated sedimentslava flows

Founders of Historical Geology

Johann Lehmann 1719-1767Georg Füchsel 1722-1776

Came up with classification similar to that of ArduinoDeveloped stratigraphic successions of rocks in Thuringia,

and the Hartz and Ertz Mountains.Began to understand the events that lead

to mountain building

Lehmann

Founders of Historical Geology

Peter Simon Pallas 1741-1811

Improved geologic history of the mountains of EuropeDeveloped the general geologic history of the UralsObserved changes in rock assemblages going from margins to

the core of mountains.

Reise durch verschiedene Provinzen des Russischen Reiches 1771-1776Journey Through Several Provinces of the Russian Empire

Founders of Historical Geology

Abraham Gottlieb Werner 1749-1817

Most influential geologist of the late 18th centuryStudied at the Freiburg Mining AcademyTaught mineralogy at Freiburg.Developed the “Neptunian”

classification of rocksAll rocks of the crust were deposited

or precipitated from sea waterA universal ocean once covered the

EarthFollowers called “Neptunists”

Founders of Historical Geology

Abraham Gottlieb Werner 1749-1817

Primitive Rocks Deposited firstCame from hot, steamy fluid with many

dissolved mineralsCoarse grained igneous and metamorphic

Transition Rocks Ocean basins formed, waters cooledFossiliferous, stratified rocksDeformed rocksOcean resembled modern oceans

Founders of Historical Geology

Flötzgebirge Flat lying sedimentary rocksContained lava flows

Alluvium All unconsolidated material

Founders of Historical Geology

Where did all the water go?

Founders of Historical Geology

James Hutton 1726-1797

Father of Modern Geology

Edinburgh physician & geologist?Opponent to Neptunism

Believed fire was the answer.

Recognized change on the Earth’ssurface

(Surficial processes were active)

Developed cyclic view of Earth

“No vestige of a beginning, noprospect of an end”.

Laid foundation for uniformitarianism“The past history of our globe must be explained by what

can be seen to be happening now”.

By observing geologic processes in operation around him,Hutton could infer the origin of features observed in rocks.

“Present is the key to the past”.Archibald Geike 1835-1924

Founders of Historical Geology

Founders of Historical Geology

Geologic past has been different than today:

AtmosphereLifeMeteorite ImpactsElevation of ContinentsClimate

Rate of change and intensity varied, butprocesses are the same.

Founders of Historical Geology

Actualism Natural laws governing both past and present processes on Earth have been the same.

Hutton observed that for all the processes to be active, immense time was needed.

Exploration of Siccar Pointrecognized the vastness of time

recognized unconformable relationships in the rocks

unable to determine the age relationships.

"The mind seemed to grow giddy by looking so far into the abyss of time.".