The rapakivi granites (1.7 to 1.55 Ga) of southern Finland occur as epizonal batholiths (e.g., the Wiborg, Åland or Ahvenanmaa, Vehmaa, and Laitila batholiths) and stocks cutting the medium- to high-grade metamorphic Svecofennian (1.9 to 1.8 Ga) crust. Emplacement of the granites was associated with faulting and the intrusion of coeval sets of mainly west-northwest- (some north-northeast) trending diabase and quartz porphyry dikes, indicating an extensional continental tectonic regime. The rapakivi granite batholiths and stocks are multiple intrusions, several of which also contain minor anorthositic and gabbroic bodies. Granites of the early intrusive phases commonly crystallized from water-deficient magmas and contain biotite and hornblende (± fayalite) as dark constituents. The younger intrusive bodies contain biotite as the only ferromagnesian silicate, whereas the youngest, water-saturated intrusive phases are topaz-bearing granites, in which the dark mica is lithium-bearing siderophyllite. Fluorite, zircon, allanite, apatite, anatase, magnetite, and ilmenite are typical accessory minerals in the granites of the early and main intrusive phases. The biotite granites contain monazite instead of allanite, and the late-stage granites contain topaz, monazite, ilmenite, Nb- and Ta-rich cassiterite, and columbite as common accessory minerals. Topaz-bearing quartz porphyry dikes and greisen-type tin-polymetallic mineralization are often associated with the last intrusive phases. The rapakivi granites are metaluminous to slightly peraluminous rocks characterized normally by high K, K/Na, Fe/Mg, F, Ga, Rb, Zr, Hf, Th, U, and REE. The early and main intrusive phases are enriched in LREE and show deep Eu anomalies. The last minor intrusive phases show flattened normalized REE patterns with still deeper Eu minima. As a result of extreme differentiation and superimposed alteration, they are anomalously enriched in F, Ga, Rb, Sn, and Nb, and are impoverished in Ti, Ba, Sr, and Zr. The rapakivi granites exhibit geochemical characteristics of subalkaline A-type granites and within-plate granites. Nd isotopic studies from the northern part of the Wiborg rapakivi area indicate that the rapakivi-age diabase dikes [∊ Nd ( T ) values +1.6 to −1.0] crystallized from mantle-derived magmas that had experienced variable degrees of crustal contamination. The rapakivi granite-quartz porphyry magmas [∊ Nd ( T ) values −0.8 to −1.9] most probably originated by partial melting of the Svecofennian crust formed 0.2 to 0.3 b.y. earlier. Heat flow from the mantle-derived magmas contributed to the partial melting.

Abstract Rapakivi granites were in use during the Middle Ages in Finland. Their most spectacular use, however, was for structures built in St Petersburg between 1760 and 1917. Remarkable examples are the majestic and slender Alexander Column and the 112 columns of St Isaac's Cathedral. All Rapakivi granite was extracted from the Wiborg Rapakivi granite batholith in several quarries around the municipality of Virolahti in SE Finland (old Russia). Today, the 1640 Ma-old Wiborg batholith is the most important area for natural stone production in Finland and in the Leningrad region, Russian Federation. The main quarried stone varieties of Rapakivi granite (Baltic Brown, Baltic Green, Carmen Red, Karelia Red, Eagle Red and Balmoral Red) are regularly produced in large quantities in Finland for the global stone market due to the stone's unique qualities. Examples of applications in Rapakivi granite from Finland can be found in the USA, China, South Africa, the UK, Italy, Austria, Ireland, Spain and Germany as well as in Scandinavia and Russia. There are also quarries near Vyborg, the Russian Federation: Vozrozhdenie and Ala-Noskua.

Abstract We report new palaeomagnetic and isotope age data of Early Mesoproterozoic (i.e. Subjotnian) intrusions from the Åland archipelago, SW Finland. The palaeomagnetic results reveal dual-polarity magnetizations with a pronounced reversal asymmetry occurring in dykes. We explain the asymmetry by an unremoved secondary component, which is affecting more N-polarity dykes. Other explanations, such as the age difference of magnetization between normal and reversed polarity dykes, are discussed. The primary nature of magnetization in dykes for both normal (N) and reversed (R) groups is verified by positive baked contact tests. A dyke showing reversed polarity from Korsö is dated 1575.9±3.0 Ma (U–Pb) in this study. This and previous U–Pb data tighten the magmatic activity in Åland to 1580–1570 Ma. We combined new palaeomagnetic data with those from earlier studies to provide a new key-palaeomagnetic pole for Baltica. Our data positions Baltica on equatorial latitudes, supporting the NENA (North Europe–North America) connection between Baltica and Laurentia at 1.59–1.58 Ga. Palaeomagnetic data support that NENA was valid at 1.75, 1.58, 1.46, and 1.26 Ga, forming the core of Mesoproterozoic Nuna (a.k.a. Columbia) supercontinent.

Abstract Baltimore, the Monumental City, was founded in 1729. One of the oldest large cities in the United States, it has had a long history of stone use. This chapter discusses the stone used for a number of iconic Baltimore monuments and buildings, including the Battle Monument, the Washington Monument, the neo-classical Basilica of the Assumption, the neo-Gothic Mount Vernon Place United Methodist Church, Transamerica Tower (Baltimore’s tallest building), and a number of other structures, providing an overview of the major stone types used in the city during the nineteenth and twentieth centuries. The general trend over this time is a shift from use of local and regional stone to use of stone from a variety of sources, including stone from Europe and Asia. This trend is most apparent in stone used for building exteriors. The various stones used have different properties, which affect their susceptibility to weathering. These include serpentinites, marbles, and brownstones that are particularly prone to weathering.