GEOL 102 mid term study (part 3)

lectures 5-6

Which of the following sediments is typical of the deep oceans?

siltstone and mudstone (or shale)

Which of the following is a transitional (from continental to marine) environment of deposition?

Delta

Which of the following minerals is abundant in modern coral reefs and carbonate platforms but is unstable and rarely found in ancient carbonate rock

Aragonite

______ refers to the grain size range of a siliciclastic sedimentary rock.

Sorting

A matrix-supported and poorly sorted conglomerate with large angular boulders was most likely deposited from______________.

 

a glacial moraine environment

The rock record distinguished by its lithology, texture, and sedimentary structures that can tell you about the ancient depositional environment is called a____________.

Facies

Carbonate sediments are most common in _________________.

 

warm and clear shallow oceans

Turbidites are most likely to be found in this depositional environment:_________.

 

submarine fans in continental slope and basin

Ancient current directions (paleocurrents) of moving water can be determined by direct study of____.

 

cross bedding and asymmetric ripple marks

In modern marine environments, corals typically inhabit warm, tropical to subtropical oceans within 30° latitude. During a trip to Mongolia, Dr. Lingeton discovered Cretaceous-aged coral fossils from marine environments at paleolatitudes of 45–60°. This finding suggests that during the Cretaceous Period, when dinosaurs thrived on Earth’s surface, the climate was _______today’s.

 

warmer than

The formal stratigraphic (rock) unit lower in rank than a Formation is a ______________.

Member

When you read a geological map, which of the following information can tell you that the sedimentary rocks are folded?

 

the dips of sedimentary rocks

A sandstone that consists of 90% quartz has _______compositional maturity than a sandstone that is composed of 90% rock fragments.

higher

Siltstone layers with mud cracks and current ripples on the surface were most likely deposited from ____.

 

tidal flat environment

Sea-level fall or regression would result in which of the following depositional sequences?

 

coarsening-upward sequence

The rock equivalent of a Period is a (an) _____________.

System

In Walther’s facies law, only geographically adjacent depositional environments can overlap their depositional facies together vertically. The following diagram shows the modern depositional environments. If the sea-level rises 100 m, the vertical facies stacking at location 1 would be, from the bottom to the top:

Facies 4→Facies 3→Facies 2→Facies 1

The stratigraphic correlation method using carbon isotope (δ¹³C) profiles of stratigraphic units is called __________.

chemostratigraphy

In modern depositional environments, from the coast (beach, for examples) to outer shelf to slope depositional environments (e.g., the New Jersey shelf), sediments change from coarse- to medium-grained sandstone to fine-grained sandstone and to siltstone and shale (fining towards the deeper ocean). If the polar ice sheets melt and a major seawater transgression happens in the next 10⁴ -10⁵ years, the sedimentary record of this process would be a ____________. 

 

fining-upward sequence

Lithostratigraphic units (e.g., Groups, Formations, Members) composed of similar lithologies imply they were formed during the same time periods.

False