Earth Science Lab Final (Answered) Complete Verified Solution

Earth Science Lab Final (Answered) Complete Verified Solution Noncomformity 1) Younger sedimentary rocks on top of older metamorphic or intrusive igneous rocks 2) Imply period of uplift of deeply buried rocks Three types of uncomformities angular uncomformity, disconformity, and noncomformity Radiocarbon dating Using the carbon-14 isotope to date very recent events (Half-life of carbon-14 is only 5,730 years) (Only useful for dating events from historic past and very recent geologic history because Carbon-14 is present in small amounts in all organisms) Divisions within the geologic time scale 1) eons divided into -- eras (Phanerozoic includes Paleozoic, Mesozoic, and Cenozoic) 2) eras divided into -- periods 3) Periods divided into -- epochs Types of rock deformation 1) elastic deformation: stress is gradually applies and rocks return to original size and shape whens tress is removed ductile and brittle deformation happen when elastic limit is surpassed 2) Brittle deformation: results in fractures and common at/near the surface 3) Ductile deformation: solid-state flow at great depths, produces a change in the size and shape of a rock, some chemical bonds break and new ones form ____ structures formed by ductile deformation and are wavelike undulations that form when rocks bend under compression. folds types of folds 1) symmetrical fold: Limbs are mirror images 2) asymmetrical fold: Limbs are different 3) overturned fold: One or both limbs are tilted beyond the vertical ____ allows scientists to accurately determine numerical ages for rocks representing important events in Earth's past. radiometric dating ______ are determined placing rocks in the proper sequence of formation (comparing it to the others' ages) relative dating Principle of superposition Older layers of sediment will be on the bottom and the younger layers will be on the top 1) In an undeformed sequence of sedimentary rocks, each bed is older than the one above and younger than the one below 2) Also applies to lava flows and ash beds 3) developed by Nicolas Steno in the mid 1600s Principle of original horizontality 1) Layers of sediment are generally deposited in a horizontal position 2) Rock layers that are flat have not been disturbed 3) Folded or inclined rocks must have been disrupted after deposition 4) Sedimentary layers laid down first and destructive event caused these layers to fold Principle of Lateral Continuity 1) Sedimentary beds originate as continuous layers that extend in all directions 2) Identical strata on two sides of a canyon were continuous before the canyon was carved Principle of Cross-cutting relationships 1) Geologic features that cut across rocks must form after the rocks they cut through 2) Faults, igneous intrusions Inclusions 1) Fragments of one rock unit enclosed within another 2) Rock that contains inclusions is younger than the rock that provided the inclusions Uncomformities 1) Interrupting the deposition of sediment creates a break in the rock record called an unconformity 2) Represents a period when deposition stopped, erosion occurred, and then deposition resumed 3) Generally, uplift causes deposition to stop and subsidence causes deposition to resume angular uncomformity 1) Consists of tilted or folded sedimentary rocks overlain by younger, more flat lying strata 2) Deformation occurred during the time that deposition stopped Disconformity A break in the rock separating younger and older sedimentary 1) A break in sedimentary rock strata representing a time when erosion occurred 2) Difficult to identify because layers are parallel 3) Evidence of erosion (buried stream channel) ______ the small internal cavities and pores of an original organism that are filled with precipitated mineral matter. Petrification ("petrified" means turned to wood) (ex: fossilized food) Cast The space once occupied by a dissolved shell or other structure is subsequently filled with mineral matter (ex: trilobite fossil) Carbonization Preservation that occurs when fine sediment encases delicate plant or animal forms an leaves a residue of carbon. (impressions may show a considerable amount of detail) ________ is a replica of an organism, such as a leaf, left in fine-grained sedimentary rock. Impression _______ is hardened resin of ancient trees that preserved delicate organisms such as insects. Amber _________ is traces of prehistoric life but not the organism itself. Indirect evidence (trace fossils) (or fossil dung?) Trace fossils Indirect evidence of organisms - tracks -burrows -coprolites -gastroliths (stomach stones) The _______ ocean covers the greatest area Pacific The _______ ocean is almost entirely in the Southern Hemisphere. Indian maps of the ocean (picture)