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Highlights • This is a first study of variations in rock strains along and across the Penokean orogen. • We also incorporate strains measured in the northern Archean foreland and the younger Yavapai (1750 Ma) and Mazatzal (1630 Ma) orogens. • New paleomagnetic and geochronologic data is also included as part of this regional synthesis. Abstract Strata in the Huron (2.5–2.0 Ga) and Animikie (2.2–1.85 Ga) basins were deposited on the southern margin of the Archean Superior province. These rocks were deformed during the Penokean orogeny (∼1850 Ma) followed by subsequent accretionary orogens to the south at 1750 Ma (Yavapai) and 1630 Ma (Mazatzal). Strain patterns are unique to each orogenic belt with no far-field effect: Archean Wawa terrane rocks in the Penokean foreland preserve deformation associated with Archean accretion with no younger Penokean, Yavapai or Mazatzal strain overprint. The Penokean orogeny deformed Huron-Animikie basin sediments into a north-vergent fold-and-thrust belt with no Yavapai or Mazatzal strain overprint. Yavapai orogen strains (SW-NE margin-parallel shortening) are unique when compared to the younger Mazatzal shortening (N20°W) shortening, with no strain overprint. Penokean deformation is characterized by shortening from the south including uplifted Archean gneisses and a northerly thin-skinned fold-and-thrust belt, with north-vergent nappes and a gently-dipping foreland. Our study of finite and calcite twinning strains (n = 60) along (∼1500 km) and across (∼200 km) the Penokean belt indicate that this orogeny was collisional as layer-parallel shortening axes are parallel across the belt, or parallel to the tectonic transport direction (∼N-S). Penokean nappe burial near the margin resulted in vertical shortening strain overprints, some of which are layer-normal. The Sudbury impact layer (1850 Ma) is found across the Animikie basin and provides a widespread deformation marker with many local, unique strain observations. We also report new geochronology (U-Pb zircon and apatite) for the gneiss-mafic dike rocks at Wissota (Chippewa Falls, WI) and Arbutus (Black River Falls, WI) dams, respectively, which bears on Penokean-Yavapai deformation in the Archean Marshfield terrane which was accreted during the Penokean orogen. Pseudotachylite formation was common in the Superior province Archean basement rocks, especially along terrane boundaries reactivated by contemporaneous Penokean, Trans-Hudson, Cape Smith and New Quebec deformation. In the hinterland (south), the younger Yavapai orogen (1750 Ma; n = 8) deformation is preserved as margin-parallel horizontal shortening (∼SW-NE) in Yavapai crust and up to 200 km to the north in the Penokean thrust belt as a strain and Barrovian metamorphic overprint. Mazatzal deformation (1630 Ma; n = 16) is preserved in quartzites on Yavapai and Penokean crust with layer-parallel and layer-normal shortening strains oriented N20°W. [ABSTRACT FROM AUTHOR]

Detrital zircons from the upper Cambrian-Devonian sandstones (Crashsite Group; n = 485) and Carboniferous tillite (Whiteout Conglomerate; n = 81) of the Ellsworth Mountains, Antarctica record a steady supply of Neoproterozoic (“Pan-African”) orogeny (~ 550–600 Ma), Grenville (~ 1000 Ma) and Neoarchean (~ 3000–3500 Ma) zircons into the northern marginal basin of Gondwana. The overlying Permian Glossopteris -bearing Polarstar Formation shales (n = 85) have the same zircon provenance as underlying units but also include a dominance of depositional-age (263 Ma) euhedral zircons which are interpreted to be of local, volcanic arc origin. Modeling of detrital zircon provenance suggests that source areas were present in Pan-African and Laurentian crust throughout the Paleozoic. We also report calcite twinning strain results (12 strain analyses; n = 398 twins) for the Cambrian Minaret Fm. in the Heritage range which is predominantly a layer-parallel shortening strain in the direction (WSW-ENE) of Permian Gondwanide orogen thrust transport. There is a secondary, sub-vertical twinning strain overprint. The initiation of localized lower-middle Cambrian rifting (Heritage Group deposition) in Grenville-aged crust as Gondwana amalgamated and the subsequent Jurassic counterclockwise rotation of the Ellsworth-Whitmore terrane out of the Permian Gondwanide belt into central Antarctica each remain tectonic curiosities. [ABSTRACT FROM AUTHOR]

Abstract: Adoptive T-cell therapy is an attractive option for targeting tumors associated with Epstein-Barr virus. In immunogenic Type III latency tumors such as post transplant lymphoproliferative disease, EBV-specific CTL have been used successfully as prophylaxis and treatment. In Type II latency malignancies such as Hodgkin''s disease and nasopharyngeal cancer, a more restricted array of EBV antigens are encoded and the clinical response rates after infusion of EBV-specific CTLs have been lower. Current strategies to increase response rates include targeting CTL to subdominant EBV antigens and genetically modifying CTL to increase their potency. [Copyright &y& Elsevier]

Abstract: Mafic dykes of different ages were collected from three different tectonic settings and analyzed using anisotropy of magnetic susceptibility (AMS) as a proxy for magmatic flow during intrusion. In Iceland, ridge-parallel basaltic dykes were sampled on each side of the active tectonic boundary. The dykes are <10 m wide along a 1–2 km strike, and are the result of a single intrusion from 1–2 km deep magma chambers in oceanic crust. Thirteen samples were collected (7 N. American plate; 6 European) and 153 cores were analyzed by AMS and preserve a vertical K max orientation indicating vertical emplacement. The Eocene Aishihik dyke swarm intrudes the Yukon–Tanana terrane in the Yukon province, Canada over an area ~200 by 60 km. These dykes were intruded normal to the accretionary margin, are porphyritic andesites, and have an intermediate geochemical signature based on major and trace element analyses. Ten dykes were sampled and 111 cores analyzed using AMS, and the dykes preserve a vertical K max orientation, indicating intrusion was vertical through ~30 km of continental crust. The 2.06 Ga Kenora–Kabetogama dykes in northern Minnesota and western Ontario crosscut a variety of Archean terranes (thickness~50 km) in a radiating pattern. The unmetamorphosed basaltic dykes are 1–120 m wide, 10–110 km in length, are vertical in orientation and can be grouped as either being single intrusion or multiple intrusion (composite) dykes. AMS data preserve a vertical K max orientation for the southerly locations (2 dykes, n =53) and horizontal K max for the remainder to the northwest (15 dykes, n =194). Maximum magnetic susceptibility axes (4 dykes, n =92) for composite dykes are scattered and yield inconsistent flow directions with regard to the dyke margin. Almost all of our results are “normal” in that, the magnetic foliation (the plane containing K max and K int, normal to K min) is parallel to the dyke planes, which gives us confidence that the magnetic lineations (i.e., K max orientations) are parallel to magmatic flow. [Copyright &y& Elsevier]

Abstract: Lithologies of two formations in the frontal ranges of the Cape Fold Belt, South Africa, host synorogenic calcite precipitated at low metamorphic grade during the end-Permian deformation of this Gondwana-wide orogen. The calcite crystals are mechanically twinned and this deformation is linked to both folding and the formation of an axial planar cleavage with associated extensional veins. Twinning strain analysis reveals a complex, rotational synfolding history in the upper, thin-layered Prince Albert Formation. Twinned calcite within the fold preserves two unique strain events. The primary shortening strain fabric is layer-parallel and transport-parallel (∼north–south). The shortening strain overprint (−5.82%) is layer-normal and plunges steeply to the northeast. These results are inconsistent with a flexural-slip folding mechanism. By contrast, a homogeneous syn-cleavage stress–strain field is recorded in the underlying, massive thick-bedded Dwyka Tillite. Analyses of calcite twins in clast-hosted, syn-cleavage fibrous calcite and rare limestone clasts define a sub-horizontal N–S shortening, and sub-horizontal, E–W extension. The intermediate axis (ε 2) is vertical and preserves shortening (−5.3%). The extension axis (ε 3) is horizontal and parallel to the clast ‘tension gash’ (fracture) plane. These deformed syn-cleavage calcite materials provide an independent constraint to the debate about contemporaneous stress–strain fields associated with folding and formation of an axial planar cleavage. [Copyright &y& Elsevier]

Abstract: Near Granite Falls, Minnesota sub-parallel pseudotachylyte, mafic dikes, and calcite veins crosscut Archean granulite facies rocks in the Minnesota River valley adjacent to the north-dipping Yellow Medicine Shear Zone (YMSZ; N80°E) that separates the Montevideo and Morton tectonic terranes. The docking of these two Archean terranes occurred prior to intrusion of the 2.067 Ga Kenora-Kabetogama dike swarm as demonstrated by aeromagnetic anomalies (correlated with field exposures) that cross the YMSZ without offset. Tectonic adjustments along the YMSZ associated with the Penokean Orogeny (∼1.8 Ga) are likely responsible for pseudotachylyte formation. Pseudotachylyte is exposed in 22 sub-parallel veins (∼N80°E, 90°) each less than 2 cm wide across an outcrop width of 45 m. The pseudotachylyte matrix is commonly banded, and contains crystal fragments (quartz, plagioclase, amphibole, rutile, apatite, ilmenite, ulvöspinel), magnetite microlites, flow banding swirls, amygdules (filled with calcite, ankerite and siderite), collapsed vesicles, and abundant lithic clasts. Pseudotachylyte formed in a number of phases. Kinematic reconstruction is complex, utilizing winged porphyroclasts, S-C structures in the country rock, and fault drag indicators along the pseudotachylyte zones. Dextral motion along the YMSZ is the most common observation. Mechanically twinned calcite within amygdules in the pseudotachylyte preserves horizontal shortening normal to the pseudotachylyte strike. Calcite veins are apparently contemporaneous with the pseudotachylyte; one set preserves twinning strains identical to the calcite amygdule strains, and the second set contains a horizontal, vein-parallel (N70°E) shortening strain. The pseudotachylyte contains a flow fabric, as determined by AMS techniques, that is a proxy for vertical flow (K max is vertical). The Kenora-Kabetogama dikes, identified geochemically, are locally parallel to the pseudotachylyte and the adjacent YMSZ tectonic suture and preserve a vertical-to-horizontal, dike-parallel AMS fabric from east (Franklin) to west (Granite Falls). Hornblende andesite dikes (055°, 1.8 Ga) are not found south of the suture, are not associated with pseudotachylyte and have a different paleopole and AMS fabric. [Copyright &y& Elsevier]

Derby Dome, a doubly plunging anticline (7×3 km) on the eastern flank of the Wind River Range, Wyoming, trends NW–SE in response to the regional NE–SW directed shortening of the Cretaceous–Eocene Laramide orogeny. Mesozoic sediments are exposed around the fold hinge above an east-dipping thrust fault that offsets Archean crystalline rocks at depth. Stress and strain ellipsoidal data were determined through the measurement of mechanically twinned calcite in limestones (Triassic Alcova through J–K Morrison Formation rocks; 13 samples), calcite cements (5 samples), and synfolding calcite veins (16 samples) around the northern half of the fold. On the outer limbs of the fold the maximum shortening strain axis (−3.5%, 15% NEVs) in the limestones and cements is sub-horizontal, layer-parallel and normal (NE–SW) to the fold hinge reflecting regional Sevier–Laramide shortening. This regional layer-parallel strain fabric is rotated into a fold axis-parallel orientation (NW–SE) near the fold hinge indicating that significant rotations occurred during folding. Synfolding calcite veins, of varying orientations, also preserve a local sub-horizontal, hinge-parallel shortening strain (−4.0%, 17% NEVs), suggesting that the regional Laramide stress and strain field was locally rotated into parallelism with the fold during shortening and displacement on the underlying thrust fault. In both the country rock, cement and vein data sets, the strain overprint noise (NEVs) increases toward the fold hinge. Inferred differential stress magnitudes are also higher for the vein calcite than for the country rock limestones or cements, and there is no interpretable pattern around the fold (avg.=560 bars, range of 240–2000 bars). Fracture measurements (n=74) in different lithologies have different orientations on each side of the adjacent Dallas Dome Fold suggesting layer-parallel rotation during folding, or active fracturing occurred uniquely on each fold limb. [Copyright &y& Elsevier]

The Cretaceous oceanic crust of the Caribbean plate has a long and complex tectonic history as an indentor plate bounded by transcurrent faults (N and S) and subduction margins (W [east slab dip] and E [west slab dip]) with no strain data. Miocene forearc sediments and accreted ophiolites are exposed along the central Pacific coast of Costa Rica and preserve a variety of folding and faulting styles. These clastic sediments, deposited in the forearc as the Middle America trench evolved, contain calcite cements and are cross cut by calcite veins. Analysis of the mechanical twins in these two calcite groups (8 samples, n = 267 twins) at Punta Dominical and the Nicoya Peninsula ophiolite preserve a consistent sub-horizontal shortening strain that is oriented parallel to the current trench axis, as are most of the accretion-related fold axes. Differential stress magnitudes for the calcite twinning strain average −450 bars, and there is little evidence of a twinning strain overprint (low NEVs). Obduction along the Middle America trench involves, in part, a component of trench-parallel horizontal shortening. The Motagua fault originates in the Middle America trench and strikes east as the northern boundary of the Caribbean plate as a sinistral margin. The Roatan Islands are a series of islands composed of south-dipping rocks along the southern side of the Motagua fault. Recent, deformed clastic sediments are drapped over gneisses, schists (40Ar-39Ar biotite age of 14 Ma), conodont-free marbles and ophiolitic fragments of presumed Cretaceous age. Twinning studies (n = 6 samples, n = 425 twins) of these marbles preserve a N–S, horizontal shortening strain, normal to the sinistral plate boundary. Differential stress magnitudes for the calcite twinning strain average −36 MPa. Only in a combined sample (n = 189 grains) is a strain overprint (high NEVs; n = 47) present, which records horizontal shortening strain at 132°, 5°. Jamaica is also along the eastern Motagua fault (Cayman trough) and twinning strain studies in Eocene limestones and younger calcite veins (n = 4 samples; n = 136 twins) preserve a horizontal shortening strain normal to the sinistral plate boundary. Twinning strain results are compared to regional GPS, focal mechanism and SKS anisotropy results around the Caribbean plate, especially along the Middle America trench on the western margin of Costa Rica with some new insights into subduction dynamics. • First study of calcite twinning strains around the Caribbean plate. • Costa Rican (Middle America trench) has a complex arrangement of focal mechanism solutions parallel to the trench, and twinned calcite preserves horizontal shortening parallel to the trench • We integrate strain data with focal mechanism solutions, geodetic data, seismicity and SKS fabrics to better understand the dynamics of the Caribbean plate. [ABSTRACT FROM AUTHOR]

Abstract: Mafic dikes pervade the upper plate of the Heart Mountain Detachment (HMD), yet the dike concentration in the lower plate is sparse. Previous workers interpreted that these dikes were emplaced either coeval with or subsequent to the emplacement of the upper plate. The magnetic fabrics of 32 mafic dikes at Cathedral Cliffs were analyzed using low-field anisotropy of magnetic susceptibility (AMS) as a proxy for flow. These dikes intrude Ordovician–Mississippian carbonate and overlying Eocene volcanic rocks and are truncated along the nearly horizontal HMD. The dikes trend between N10°W and N20°E, are all steeply dipping, and range in width between 0.5 and 3m. Flow directions for the dikes were determined by the bearing and plunge of the K max (maximum principal susceptibility) axes relative to the dike orientation. About 66% of the dikes sampled show typical dike AMS patterns with K max and K int in the plane of the dike and K min normal to the dike plane. About 66% of the dikes sampled have K max inclinations >45° and thus were emplaced upward; 16% of the dikes have K max inclinations of <10° and thus were emplaced laterally. The remaining dikes have intermediate K max inclinations. With numerous dikes showing vertical to sub-vertical emplacement directions and with no magmatic source immediately below the detachment the dikes must predate emplacement of the upper plate. Therefore, upper plate dilation by dike intrusion could not be a driving force for protracted extension. Our date is consistent with a single catastrophic emplacement event, and inconsistent with an extensional allochthon model of incremental emplacement over long intervals of time. [Copyright &y& Elsevier]