Marine Geo Exam 2

Shallow water carbonate- magnetostratigraphy

The Paleozoic, Mesozoic and Cenozoic Ears are contained within the ____Eon

Phanerozoic

Name the missing Paleozoic Era: Cambrian, Ordovician ________ Devonian

Silurian

When did the Cenozoic Era begin?

66 Ma

when did the Pleistocene Epoch begin

2.6 ma

What was the term coined by Schlager (2005) for high production of carbonate sediments occurring in the shallow, warm, sunlit portions of carbonate platforms

Carbonate Factory

Which of the following is not consistent with abundant shallow-water carbonate sediment production

upwelling of nutrient-rich waters

Biologically-induced formation of shallow-water carbonates (such as by green calcareous algae) produces a very structured, ordered skeleton

False

At pulley ridge, how does the marine chemistry support/sustain the biology of the coral reed ecosystem

provides clear water

which components together comprise the continental margin

shelf/slope/rise

Wide continental shelves are consistent with _____ margins, and continental sheld waters depths rarely exceed ______

passive; 150 m

Offshore facies

mud dominant, rare sandy storm deposits (tempestites)

Shoreface facies

Sand-dominant, swaley cross-stratification if storm-dominated shelf

Forshore facies

sands. swash processes, low angle seaward-dipping beds

What are the dominant sediment contributors to continental shelves

biogenous and terrigenous

this authigenic shelf sediment type is indicative of high nutrients from upwelling conditions

phosphorites

which of the following is not consistent with formation of authigenic shelf sediments

form in place

Submarine canyons are conspicuous features found on the ______

both shelf and slope

which of the following is not consistent with deep sea sediments derived from land (terrestrial)

Phosphorites

which of the following is consistent with a carbonate biogenic ooze

50% coccolith skeletal remains

the presence of this deep sea sediment type in particular indicates high biological productivity of surface waters

siliceous ooze

these deep sea sediments have the slowest accumulation rates and most widespread distribution on the deep seafloor

red clays

the solubility of ______ shells increases with increasing pressure and decreasing temperature in the ocean

carbonate

The CCD is _____ in the Atlantic than the Pacific due to ______ dissolved Co2

deeper;decreased

when carbonate organisms such as forminifera make their shells, the two primary controls on the oxygen isotope ratio in their shells are______

ince volume and temperature

During warm interglacial time periods, the o18 in the ocean waters______

decrease

Oxygen isotope analyses on ______ foraminifera would be more useful in extracting sea surface temperature changes through time

planktonic

the dominant signal influencing the O18 of seawater is ice volume

true

which is the basic unit of lithostratigraphy, which has defining characteristics such as mineralogy, grain size, and fossil content, and is laterally traceable over long distances

formation

because of laterally shifting environments through time, lithostratigraphic boundaries are described as diachronous, meaning facies boundaries _____ time lines

cross

of the following,which would be least useful in lithostratigraphy for placing the strata in a temporal framework(ie helping to tell time)

percentage mud

william smith first recognized the sediments contain fossils in a definite sequence that can be correlated with strata from other locations containing the same sequence of fossils, this observation is known as the ____

principle of faunal succession

in biostratigraphy, organisms that display high rates of speciation are more useful that organisms that display low rates of speciation

true

which of the following environments is not conducive to the preservation of fossils

slow burial

the fossil fecord is biased towards the ___ environment, and with biostratigraphy, we can narrow down the age of the strata to _____

marine; tens of thousands of years

an advantage in using magnetostratigraphy is the polarity reversals appear to be geologically instantaneous

true

which type of remnant magnetization occurs as magma/lava cools below the curie point of minerals in the magma

thermal

it is useful for using magnetostratigraphy that magnetic field reversals occur at ______ frequency

irregular

Because of ocean circulation patterns, shallow water oral reefs are most prevalent on the ___ side of ocean basins

Western

these deep sea sediment have the fastest accumulation rates on the seafloor

turbidites

unlike siliciclastic sediments, shallow-water carbonate sediments cement rapidly

true

These inorganically precipitated, layered, spherical carbonate grains indicate formation in a shallow-water, high-energy setting

ooids

which authigenic sediment formed on continental shelves is consistent with precipitation of ferriciron from seawater or by chemical alteration of clay minerals in seawater

glauconite

what is the basic unit of magnetostratigraphy

chron