Labrador , nickname = "The Big Land" , etymology = , subdivision_type = Country , subdivision_name = Canada , subdivision_type1 = Province , subdivision_name1 ...

, Canada, the

North Atlantic Craton The North Atlantic Craton (NAC) is an Archaean craton exposed in southern West Greenland, the Nain Province in Labrador, and the Lewisian complex in northwestern Scotland. The NAC is bounded by the Nagssugtoqidian orogen to the north and the 1.8 ...

is known as the Nain Province. The Nain geologic province was intruded by the Nain Plutonic Suite, which divides the province into the northern Saglek block and the southern Hopedale block.

North Atlantic Craton

The North Atlantic Craton is exposed in parts of the coast of Labrador, parts of central

Greenland Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland is t ...

, the Scourian Complex of northwestern

Scotland Scotland (, ) is a country that is part of the United Kingdom. Covering the northern third of the island of Great Britain, mainland Scotland has a border with England to the southeast and is otherwise surrounded by the Atlantic Ocean to the ...

and is unexposed in northern

Norway Norway, officially the Kingdom of Norway, is a Nordic country in Northern Europe, the mainland territory of which comprises the western and northernmost portion of the Scandinavian Peninsula. The remote Arctic island of Jan Mayen and t ...

. The North Atlantic Craton fragmented 2450 to 2000 million years ago. When North America and Europe rejoined, the North Atlantic Craton was triangular shaped with each side ; this unit was separated when the

Labrador Sea The Labrador Sea (French: ''mer du Labrador'', Danish: ''Labradorhavet'') is an arm of the North Atlantic Ocean between the Labrador Peninsula and Greenland. The sea is flanked by continental shelf, continental shelves to the southwest, northwest, ...

formed 61 to 40 million years ago. The crust of the North Atlantic Craton varies between thick and its rocks are 85%

granitoid A granitoid is a generic term for a diverse category of coarse-grained igneous rocks that consist predominantly of quartz, plagioclase, and alkali feldspar. Granitoids range from plagioclase-rich tonalites to alkali-rich syenites and from quartz ...

gneisses. The Nain Province was intruded by the 1350- to 1290-million-year-old Nain Plutonic Suite; composite anorthosite-granitic

intrusion In geology, an igneous intrusion (or intrusive body or simply intrusion) is a body of intrusive igneous rock that forms by crystallization of magma slowly cooling below the surface of the Earth. Intrusions have a wide variety of forms and com ...

s which divide the Nain Province into the northern Saglek Block and the southern Hopedale Block.

Nain Province

In Labrador, the North Atlantic Craton is known as the Nain Province or Nain Craton. The Nain Province is more than long and wide. The

gneiss Gneiss ( ) is a common and widely distributed type of metamorphic rock. It is formed by high-temperature and high-pressure metamorphic processes acting on formations composed of igneous or sedimentary rocks. Gneiss forms at higher temperatures an ...

es of the Nain Province were last deformed and metamorphosed when two blocks docked together 2500 million years ago with a collisional boundary extending to the north and to the south of Nain, Labrador, Canada. These two blocks appear to represent two distinct

Archean The Archean Eon ( , also spelled Archaean or Archæan) is the second of four geologic eons of Earth's history, representing the time from . The Archean was preceded by the Hadean Eon and followed by the Proterozoic. The Earth Earth ...

cratonic nuclei, each with its own mineral depositional history. Major granitic intrusions – the Wheeler Mountain, Halbach, Alliger, Sheet Hill, Loon Island,

Red Island Red Island may refer to: * Red Island, Newfoundland and Labrador * Red Island, Queensland * Red Island (Antarctica) * Red Island (Grenadines), in St Vincent and the Grenadines * Red Island Holiday Camp, in Ireland *Rhode Island, meaning red island * ...

, and Satok Island intrusions – form a north-trending linear chain which have a southerly decrease in age – 2135-million-year-old Wheeler Mountain granite in the north to the 2025-million-year-old Satok Island monzonite in the south. The Nain Province was then intruded by the 1350- to 1290-million-year-old Nain Plutonic Suite; composite anorthosite-granitic intrusions which divide the Nain Province into the northern Saglek block and the southern Hopedale block. The Torngat orogen developed during the oblique convergence of the

Superior Superior may refer to: *Superior (hierarchy), something which is higher in a hierarchical structure of any kind Places *Superior (proposed U.S. state), an unsuccessful proposal for the Upper Peninsula of Michigan to form a separate state *Lake ...

and Nain Provinces 900 million years ago. The

crystal A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macros ...

line crust in the Nain Province is thick; it thins to thick in the shelf area of the Labrador margin, where it is covered with up to of sediments.

Saglek block

The 3800- to 3300-million-year-old Saglek block is long and wide; it has a north-northwesterly trend from Nain, Labrador, extending nearly to the northern tip of Labrador. This block is a high-grade gneiss

terrane In geology, a terrane (; in full, a tectonostratigraphic terrane) is a crust fragment formed on a tectonic plate (or broken off from it) and accreted or " sutured" to crust lying on another plate. The crustal block or fragment preserves its own ...

; it has no

greenstone belt Greenstone belts are zones of variably metamorphosed mafic to ultramafic volcanic sequences with associated sedimentary rocks that occur within Archaean and Proterozoic cratons between granite and gneiss bodies. The name comes from the green ...

s. Within the gneiss are variably-sized enclaves ranging from anorthosite to

ultramafic Ultramafic rocks (also referred to as ultrabasic rocks, although the terms are not wholly equivalent) are igneous and meta-igneous rocks with a very low silica content (less than 45%), generally >18% MgO, high FeO, low potassium, and are composed ...

. There are also three small anorthositic, ultramafic meta-igneous complexes in the gneiss near Okak Bay. The northward–trending Handy fault separates the Saglek block into two metamorphic parts. The gneiss complex on the western side of the Handy fault has rocks that crystallized under granulite facies conditions; this western block is more deeply exposed than the eastern one. On the eastern side

amphibolite facies Amphibolite () is a metamorphic rock that contains amphibole, especially hornblende and actinolite, as well as plagioclase feldspar, but with little or no quartz. It is typically dark-colored and dense, with a weakly foliated or schistose (flak ...

rocks are exposed in the northern part; they transition to granulite facies to the south. The total crustal thickness is north of the fault and south of the fault.

Hopedale block

Hunt River and Florence Lake greenstone belts

The 3100- to 2800-million-year-old Hopedale block is long and wide. Hopedale, Labrador, is at the eastern midpoint. This block contains the 3100-million-year-old Hunt River and 3000-million-year-old Florence Lake greenstone belts, and the Weekes amphibolite which represents remnants of the older Hunt River greenstone belt.

References

{{coord , 56.58, N, 62.06, W, display=title Geologic provinces of Canada Historical tectonic plates Cratons Greenstone belts Geology of Newfoundland and Labrador