Rodinia

Sims et al. (1989) synthesized U-Pb zircon ages for the Pembine-Wausau terrane. Sims concluded that the volcanic rocks were generated from around 1889 to 1860 Ma as island arcs and closed back-arc basins above the south-dipping subduction zone (Niagara fault zone). Granitoid rocks in the terrane, emplaced from around 1870 to 1760 Ma, are mainly granodiorite and tonalite but include gabbro, diorite, and granite. These developed as island arcs above the Eau Pleine shear zone. The Niagara fault zone contains a relict ophiolite, suggesting that the rocks in the Pembine-Wausau terrane probably accumulated on

According to the theory of “Pangaea,” the world was once a single mega-continent that contained all the dry land about 225 million years ago. North America was shaped by the majestic Canadian Shield about 10 million years ago.

Rodinia started to rift around 750 to 600 million years ago and the Iapetus Ocean opening up as seen in Figure 1, the Swift Run Formation with Grenville, volcanic debris and ash material produced the Catoctin Formation that contains flood basalts supporting Shenandoah. With modern day East Africa rift and Red Sea curst stretched, this allowed flood basalts and rhyolite seep through the ocean floor and eventually made its way to the surface.

About 225 million years, all of the world’s land was contained in one supercontinent, named Pangea. This supercontinent would eventually separate itself into the continents that are known today, due to continuous movement of the earth’s tectonic plates, which led to major shifting and folding of the earth’s crust. This shifting formed many of the mountain ranges that exist today, such as the Appalachians and the Rocky Mountains. However, the time of Pangea’s separation into multiple continents and the time of the formation of the mountain ranges aren’t synonymous; for instance, the Appalachians were most likely formed before Pangea’s separation. About some 2 million years ago, a Great Ice Age befell the earth, which caused a

2. The process by which a tectonic plate consisting of less heavy rock rides up over a heavier plate is known as:

The first deformation event (D1) resulted in folding of volcanic rocks in the Wabigoon and Wawa subprovinces (Hooper and Ojakangas, 1971; Hudleston, 1976; Hudleston et al., 1987; Jirsa et al., 1992) and locally within the Quetico subprovince (Bauer, 1985b). Most D1 folds in the Wawa terrane in MN rarely display axial-planar cleavage, with Bauer (1985b), Hooper and Ojakangas (1971), Hudleston (1976), and Jirsa et al. (1992) having identified cleavage (S1) development locally in the Vermillion greenstone belt (Peterson, 2001). In the Wabigoon terrane, D1 resulted in recumbent folding that overturned the stratigraphic sequence and the first regional schistosity (Poulsen et al., 1980). S1 is generally subparallel to the layering in the metavolcanic and metasedimentary rocks, and a gneissic foliation attributed to D1 is well developed in gneissic domes (Czeck and Poulsen, 2010). Although D1 likely created significant thrust or oblique faulting, direct evidence

However, Hildebrand, (2009, 2013) affiliate the pre Cretaceous rocks, particularly the Neoproterozoic rocks crops out in central and east Utah, to the microcontinent Rubia, but such interpretation needs translation of rocks for a very long

The basement rocks in the western Slave carton is older than 2.8 Ga and the known oldest rocks are the genesis found along the Acasta River which is about 3.6- 4.0 Ga old, which is estimated using the zircon dating (Isachsen & Bowring, 1994; Padgham,1992). Following by 2.8 - 3.5-Ga old genesis of Point Lake and genesis under the Yellowknife Greenstone belts, which exist over 3 Ga (Isachsen & Bowring, 1994; Padgham,1992). The major rock types include granitic to tonalitic genesis, migmatitic genesis and granodiorites, which have been deformed and metamorphosed (Fyson & Helmstaedt, 1988; Isachsen & Bowring, 1994; Padgham,1992). In the eastern Slave Craton, the basement is not confined but is correlated to the Nd-Pb isotopic boundaries

The Taconic orogeny is evidenced in the Hudson Valley. This orogeny has formed by the convergence of the Laurentia and the Shelburne arc. The Taconic orogeny has led to the formation of sedimentary rocks that can be classified into autochthonous and allochthonous, whereas the Normanskill formation is autochthonous, and five distinctive thrust slices from the low Taconic sequence are allochthonous. Another feature is the Cortland Complex, which is a late Ordovician magmatic intrusion formed by norite, gabbro, hornblende norite, monzodiorite, diorite, hornblende pyroxenite, and peridotite. The sedimentary rocks in the Dutchess county and Westchester counties, New York, have suffered metamorphism due to convergence activities as well as magma

The Sangre de Cristo Mountains are a structurally complex block having a Precambrian igneous core that is bounded by major, high-angle reverse faults and highly contorted, steeply dipping to overturned sedimentary beds of Paleozoic and Mesozoic age. The range resulted from uplift and eastward thrusting during the Laramide orogeny commencing in Late Cretaceous time and continuing intermittently to possibly late Tertiary time (Wanek and Read, 1956).

Laurentia as a bioregion is one of the largest bioregions that exist and has a very large degree of characteristics and variance within its biologic, geologic, and cultural attributes (Figure 1. Bioregions and Biotones). “Laurentia is a bioregion sits atop the Laurentian craton in the northeastern United States and eastern Canada, and centering on the Great Lakes. The bioregion spans the Eastern Woodlands of North America from the easternmost part of the Great Plains to the Atlantic Coast of the Northeastern

Pannotia was short lived for a supercontinent as the collisions that formed it were glancing and hence not so binding as they were for Rodinia. It lasted a mere 60 million years.

Though Geologists have a fair amount of evidence about Pangaea, there are still questions about how Pangaea looked like and how it fragmented into various continents.

The collision of Rodinia(800-750Ma) with the Congo continent which known as the Pan-African Event, was the reason behind breakup of Rodinia. As a result of this, Rodinia rifted into (East Gondwana, Cathyaisa and Cimmeria) in the north and (Laurentia, Amazonia-NW Africa, Baltica and Siberia) in the south. While the Panthalassic Ocean opened. After the next 150Ma, south Rodinia rotated across the South Pole. At the same time north Rodinia rotated to the North Pole. In the pan- Africa event the three continents the Congo continent, North and south Rodinia was collided to form Pannotia (Gretter Gondwanaland) (figure2). According to (Powell, 1995; Dalziel, 1997), that pannotie formed of “exterior “Ocean floor Mozambique Ocean. (Murphy and Nace,

The great terrain which, in the course of 300 million years, became 7 different continents broken apart and spread across the globe existed during the late Paleozoic and early Mezozoic eras. In contrast to the present Earth and its distribution of continental mass, much of Pangaea was in the southern hemisphere and surrounded by a super ocean, Panthalassa. The name is derived from Ancient Greek: pan meant entire,