Definitions
Rift Axis
What is the middle of the rift/the location of thickest lava flows?
The three subdivisions that Dickas and Mudrey gave to the MCR
What are the Iowa Zone, the Superior Zone, and the Mackinaw Zones?
How the MRS has been mapped/documented even where it is buried under younger rocks
What are geophysics utilizing gravity and aeromagnetic signature?
(When these two are high, the formation's presence is inferred from the fact that this happens when basaltic proportion is high.)
The nature of magmatic activity in the rift over time, and the inferred sources of magma.
What are fissure eruptions and basalt, with the presence of some rhyolites?
(Rhyolites form due to fractional crystallization/Bowens Reaction Series, or as seen in this context, re-melting of continental crust.)
The climate and environmental conditions when the Rift sediments were deposited.
What are alluvial fans, dry climate, high wind, high energy environment, and steep topography?
Listric Normal Fault
What is a normal fault whose angle gets gentler with depth?
The distinctions between the subdivisions given by Dickas and Mudry.
The Superior subdivision is the only one visible on the surface.
The role of the Grenville Orogeny in the MCR story
What is the cause of rift closure that prevented the formation of an ocean basin, and caused reverse faults?
The 3 big groups of Sed. rocks in the Rift, and their contribution to the story.
What are conglomerate rocks, shale rocks, and sandstones?
Basis for depositional environment inferences
*coarse sediment etc find more info
Flood Basalt
What is the name for the appearance of large basalt volumes in a short period of time? (1 million cubic kilometers/1 million years)
The overall organization of the paper
What are "Tectonics/structure/geophysics," "Paleomagnetisim and radiometric ages," "Sedimentation," and "Mineralization and Petroleum"?
The type of information that paleomagnetic analyses of Rift rocks reveals
What are polarity and paleolatitude?
Surprising factors of the stromatolites in the Copper Harbor Conglomerate
What is a high energy sedimentary environment (alluvial fans)/ potential lack of a marine environment.
Potential effect of the GLTZ on the rift
What is the parallel relationship between the GLTZ and MCR formations, due to potential influence on development and orientation?
Quiescence
What is a lull in magmatic activity/lack of action?
Magmatic sequence of events in MCR
What were major pulses of magmatism from 1109 to 1105 Ma and from 1100 to 1094 Ma, as well as early stages featuring rhyolites(such as in the North Shore Volcanic group in MN)? (427)
Significance of the polarity switch that occurred at the time that the Rift was active
What is the provision of a timeline between lava formations?
Topographic indications of the post-rift rocks' composition
What is a topographic high? (This is known due to all of the cobble in the conglomerates being from the rift itself, containing no clasts from other locations).
Differences of MCR to other rift zones
What are enormous volume of mafic igneous rock, immense volumes of plateau lavas, equivalent volume of subvolcanic and lower-crustal intrusions, large volumes of early post-rift sediments composed of nearly entirely intrabasinal volcanic and subvolcanic detritus?
Eolian
What is a word communicating relationship to wind (in this context, wind-deposited sediments)?
The sediment sequence found in the MCR
What are quartzose sandstone, immature interflow strata deposited between volcanic eruptions, the Oronto Group, and the Bayfield Group? (430)
The reason that stratigraphic layers may be missing in different parts of the Rift (Figure 6)
What are sites of active fissures and marine environments?
Active fissures change activity and location. Marine environments would accumulate that type of sediment, while the areas above water would have higher erosion rates. (Shale, Alluvial Fan Deposits)
The reason the Nonesuch Formation's possession of petroleum is remarkable
What is metamorphosis in extremely old rocks? (Most petroleum is Mesozoic or younger).
Similarities of MCR to other rift zones
What are evidence of melted rock rising, divergent boundary, infill of sediments, and marine evidence?