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The Eastern Canadian Shield Onshore-Offshore Transect (ECSOOT) of the Lithoprobe program included 1200 km of normal-incidence seismic profiles and seven wide-angle seismic profiles across Archean and Proterozoic rocks of Labrador, northern Quebec, and the surrounding marine areas. Archean crust is 33-44 km thick. P-wave velocity increases downwards from 6.0 to 6.9 km/s. There is moderate crustal reflectivity, but the reflection Moho is unclear. Archean crust that stabilized in the Proterozoic is similar except for greater reflectivity and a well-defined Moho. Proterozoic crust has similar or greater thickness, variable lower crustal velocities, and strong crustal reflectivity. Geodynamic processes of Paleoproterozoic growth of the Canadian Shield are similar to those observed in modern collisional orogens. The suturing of the Archean Core Zone and Superior provinces involved whole-crustal shearing (top to west) in the Core Zone, linked to thin-skinned deformation in the New Quebec Orogen. The Torngat Orogen sutures the Nain Province to the Core Zone and reveals a crustal root, in which Moho descends to 55 km. It formed by transpression and survived because of the lack of postorogenic heating. Accretion of the Makkovik Province to the Nain Province involves delamination at the Moho and distributed strain in the juvenile arcs. Delamination within the lower crust characterizes the accretion of Labradorian crust in the southeastern Grenville Province. Thinning of the crust northwards across the Grenville Front is accentuated by Mesozoic extension that reactivates Proterozoic shear zones. The intrusion of the Mesoproterozoic Nain Plutonic Suite is attributed to a mantle plume ponding at the base of the crust.

We compile and analyze all available geothermal heat flow measurements collected in and around Greenland into a new database of 419 sites and generate an accompanying spatial map. This database includes 290 sites previously reported by the International Heat Flow Commission (IHFC), for which we now standardize measurement and metadata quality. This database also includes 129 new sites, which have not been previously reported by the IHFC. These new sites consist of 88 offshore measurements and 41 onshore measurements, of which 24 are subglacial. We employ machine learning to synthesize these in situ measurements into a gridded geothermal heat flow model that is consistent across both continental and marine areas in and around Greenland. This model has a native horizontal resolution of 55 km. In comparison to five existing Greenland geothermal heat flow models, our model has the lowest mean geothermal heat flow for Greenland onshore areas. Our modeled heat flow in central North Greenland is highly sensitive to whether the NGRIP (North GReenland Ice core Project) elevated heat flow anomaly is included in the training dataset. Our model's most distinctive spatial feature is pronounced low geothermal heat flow (< 40 mW m−2) across the North Atlantic Craton of southern Greenland. Crucially, our model does not show an area of elevated heat flow that might be interpreted as remnant from the Icelandic plume track. Finally, we discuss the substantial influence of paleoclimatic and other corrections on geothermal heat flow measurements in Greenland. The in situ measurement database and gridded heat flow model, as well as other supporting materials, are freely available from the GEUS Dataverse (https://doi.org/10.22008/FK2/F9P03L; Colgan and Wansing, 2021).

ObjectiveTo estimate the effectiveness and safety of laparoscopic surgical excision of rectovaginal endometriosis.DesignA multicentre, prospective cohort study.Setting51 hospitals accredited as specialist endometriosis centres.Participants5162 women of reproductive age with rectovaginal endometriosis of which 4721 women had planned laparoscopic excision.InterventionsLaparoscopic surgical excision of rectovaginal endometriosis requiring dissection of the pararectal space.Main outcome measuresStandardised symptom questionnaires enquiring about chronic pelvic pain, bladder and bowel symptoms, analgesia use and quality of life (EuroQol) completed prior to surgery and at 6, 12 and 24 months postoperatively. Serious perioperative and postoperative complications including major haemorrhage, infection and visceral injury were recorded.ResultsAt 6 months postsurgery, there were significant reductions in premenstrual, menstrual and non-cyclical pelvic pain, deep dyspareunia, dyschezia, low back pain and bladder pain. In addition, there were significant reductions in voiding difficulty, bowel frequency, urgency, incomplete emptying, constipation and passing blood. These reductions were maintained at 2 years, with the exception of voiding difficulty. Global quality of life significantly improved from a median pretreatment score of 55/100 to 80/100 at 6 months. There was a significant improvement in quality of life in all measured domains and in quality-adjusted life years. These improvements were sustained at 2 years. All analgesia use was reduced and, in particular, opiate use fell from 28.1% prior to surgery to 16.1% at 6 months. The overall incidence of complications was 6.8% (321/4721). Gastrointestinal complications (enterotomy, anastomotic leak or fistula) occurred in 52 (1.1%) operations and of the urinary tract (ureteric/bladder injury or leak) in 49 (1.0%) procedures.ConclusionLaparoscopic surgical excision of rectovaginal endometriosis appears to be effective in treating pelvic pain and bowel symptoms and improving health-related quality of life and has a low rate of major complications when performed in specialist centres.

The crustal structure of the eastern Grenville and Makkovik provinces was determined using two onshore-offshore refraction seismic lines of the Lithoprobe Eastern Canadian Shield Onshore-Offshore Transect (ECSOOT). A gravity high in the Hawke River terrane correlates with increased P-wave velocities in the upper 30 km of the crust (6.2-6.7 km/s in the upper and middle crust and 6.9-7.1 km/s below) which we interpret as structure inherited from the Labradorian orogen. Velocities in the adjacent Groswater Bay terrane are 6.0-6.55 km/s in the upper and middle crust and 6.6-6.95 km/s in the lower crust. The entire Grenville crust is underlain by a 15-20 km thick high-velocity lower crustal (HVLC) wedge consisting of an upper layer (7.1-7.4 km/s) and a lower layer (7.6-7.8 km/s). The HVLC wedge is interpreted as an underplated layer formed during Iapetan rifting. This interpretation is based on the correlation with the 615 Ma Long Range dykes onshore and the eastward termination of the wedge at the Cartwright Arch. Similar HVLC layers are found offshore western Newfoundland, suggesting that the underplating may be a continuous feature along the passive Grenvillian margin. The Cartwright Arch is characterized by velocities of 6.4 km/s and 4 km thick sediment sequences (4.3-5.7 km/s) in the surrounding basin, interpreted as an extensional basin with basaltic magmatism within the arch. The Grenville front is clearly marked by a decrease of velocities in the Makkovik Province (5.8-6.4 km/s in the upper and middle crust, 6.65-6.85 km/s in the lower crust) and a gradual thickening of the crust (not including the HVLC layer) from 30 km in the Grenville Province to 35 km in the Makkovik Province.

A detailed refraction - wide-angle reflection seismic experiment was carried out in northern Labrador to determine the velocity structure of relatively unaltered Archean crust in the Nain Province. Six 3-component land seismometers were used to record an airgun source along a profile parallel to the coast. Forward modeling of traveltimes and amplitudes yields a P- and S-wave velocity model that shows two crustal blocks separated by a fault. Magnetic data suggest, but do not prove, that the fault is the offshore continuation of the Handy fault. A southwards thickening of the lower crust across the fault indicates that a transcurrent component might have been associated with the faulting. The total crustal thickness is 33 km to the north and 38 km to the south of the fault. The presence of P m S reflections imply a sharp transition at the Moho. Upper crustal velocities of 5.8-6.3 km/s and Poisson's ratios of 0.20 and 0.24, north and south of the fault respectively, are consistent with a gneissic composition, but suggest a higher quartz content in the northern block. Velocities in the middle crust increase to 6.5 km/s, where a discontinuity at a depth between 16 and 18 km marks the transition to the lower crust with velocities between 6.6 and 6.9 km/s. Poisson's ratios of 0.24 and 0.26 indicate, respectively, a felsic middle crust and an intermediate composition for the lower crust. The absence of a high-velocity basal layer is in accordance with other examples of Archean crust.

Crustal structures of the eastern Grenville, Makkovik, and southern Nain provinces are determined using seismic reflection-refraction and gravity data along the Lithoprobe Eastern Canadian Shield Onshore-Offshore Transect (ECSOOT). Within the Grenville Province, the velocity model contains a 5 km thick upper crust and a variable-thickness middle to lower crust. The total crustal thickness varies from 25 to 43 km, with the thickest crust in the south and thinnest crust in the north. A high-velocity, lower crustal wedge is coincident with a strong band of northward-dipping reflectors. The two-dimensional velocity structure is compatible with modelling of a 60 mGal gravity high over the Hawke River terrane. In the Makkovik Province, the thickness of upper crustal velocities increases to 17 km. The velocity decrease in the upper to middle crust from the Grenville Province to the Makkovik Province is similar to that of refraction models across the Grenville Front in Ontario and Quebec. It is possibly related to a decrease in metamorphic grade from south to north and (or) a larger volume of unmetamorphosed plutons in the Makkovik Province. A lower crustal layer is coincident with a region of increased reflectivity in the lower crust. There are no major crustal discontinuities associated with terrane boundaries within the Makkovik Province. The base of the crust is consistent with a change from north- to south-dipping reflectors beneath the Cape Harrison domain. Alternatively, it may consist of a thick zone of complex velocity variations, consistent with a zone of diffusive reflectivity observed to the north of the Allik domain.

A detailed refraction-wide-angle reflection seismic experiment was carried out in northern Labrador Canada to determine the velocity structure of relatively unaltered Archean crust in the Nain Province. Six 3-component land seismometers were used to record an airgun source along a profile parallel to the coast.

Crustal structures of the eastern Grenville, Makkovik, and southern Nain provinces are determined using seismic reflection-refraction and gravity data along the Lithoprobe Eastern Canadian Shield Onshore-Offshore Transect (ECSOOT). Within the Grenville Province, the velocity model contains a 5 km thick upper crust and a variable-thickness middle to lowercrust.