Burial and exhumation history of the Labrador- Newfoundland margin. - - PowerPoint PPT Presentation

Geological Survey of Denmark and Greenland Danish Ministry of Climate, Energy and Building

Burial and exhumation history of the Labrador- Newfoundland margin. Implications for hydrocarbon exploration on the Grand Banks and on the Labrador Shelf

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15-18 October 2017 » AAPG London Peter Japsen1, Paul F . Green2 Johan M. Bonow3, Alana M. Hinchey5 & Derek H.C. Wilton6

• 1Geol. Surv. Denmark, Greenland (GEUS), 2 Geotrack International, 3Geovisiona,
• 4Geol. Surv. Labrador, Newfoundland, 5Memorial University of Newfoundland

BACKGROUND

Elevated, passive continental margins (EPCMs): Common features. Common origin?

Japsen et al. 2012; Green et al. 2013

Studies of uplift and erosion along EPCMs

2014 2007,16 2012 2006 2016 Publication Unpublished

Permanent vs episodic uplift

Japsen et al. 2012

PRE-CRETACEOUS AND CENOZOIC UPLIFT AND EROSION OF LABRADOR

Labrador and Newfoundland margin Moderate elevations

• Max. 1700 m asl

Similar landscapes on the conjugate margins across the Labrador Sea

Torngat Mountains, Labrador: Elevated plain cut by a deep valley Disko, West Greenland: Elevated plain across Paleocene basalt. Result of mid-Cenozoic planation followed by late Neogene uplift (Japsen et al. 2006)

Labrador and Newfoundland

Pre-Mesozoic rocks dominate onshore Paleogene and Cretaceous strata truncated towards the landmass

Seismic line

Paleogene Cretaceous Precambrian

Post-Eocene tiling and truncation towards Labrador

Dickie et al. 2011, Mar. Petrol. Geol.

5: late Eocene. 4: base Eocene. 3: mid-Paleocene. 2’: Late Cretaceous. 2: mid-Cretaceous. 1: top basement. Sand-prone units: Gold and yellow colours.

Cretaceous outlier ⇒pre-Cretaceous denudation Schefferville

Albian, Cenomanian

Dorf 1967, Psyche

Cooling history of rocks on the coast of northern Labrador from AFTA

Pilot study sponsored by the Geological Survey of Newfoundland and Labrador: Apatite Fission-Track Analysis

11 basement samples 1 latest Precambrian sediment samles

MIOCENE EXHUMATION OF THE LABRADOR SHELF

Miocene hiatus across much of the Labrador shelf

Ainsworth et al. 2014 Nalcor report

Lithostratigraphic chart Labrador Shelf

(Nalcor 2016)

Lithostratigraphic chart Labrador Shelf

(Nalcor 2016)

Beaufort unc. Miocene hiatus Labrador unc. Base-Cretaceous hiatus Avalon unc. Mid-Cretaceous hiatus

Hopedale E-33 & S. Hopedale L-39 wells ~750 m Miocene section removed?

DTH - Default thermal history: Maturity profile predicted if all units are at maximum post-depositional temperatures

Hopedale E-33 & S. Hopedale L-39 wells ~750 m Miocene section removed?

Japsen et al. 2007, Geoph. Prosp.

• dZB, Burial anomaly

= 500 m BE, Post-Mokami reburial = 200 m dZB Missing section = 700 m

Burial History Reconstruction based on the assumption that maximum burial occurred in the late Miocene

• Deposition of 750 m

Miocene sediments

• Removal of these

sediments in the late? Miocene

Hopedale E-33 Possible burial reconstruction

Max temps pre-Neogene section

Chronostratigraphic chart Labrador Shelf

(Balkwill et al. 1990)

Chronostratigraphic chart Labrador Shelf

(Balkwill et al. 1990) Onset of Lower Saglek progradation Onset of Upper Saglek progradation Hiatus Late? Miocene exhumation “Coarse grained quartz and igneous clasts, which first appeared in the mid-Tertiary in the upper Mokami member, are evidence of the first phase of the uplift of coastal Labrador in the late Oligocene to early Miocene”

Sketch of the Neogene development of Labrador and the Labrador Shelf

• 1. Uplift of Labrador near base Miocene
• Onset of lower Saglek progradation
• Up to 1 km burial of the shelf
• 2. Exhumation in the late? Miocene
• Removal of up to 1 km thick cover, ~lower Saglek/ upper Mokami

(all the Miocene) in many wells

• Shelf-wide erosion
• 3. Uplift of Labrador near base Pliocene
• Onset of upper Saglek progradation
• Burial of the shelf (up to 1 km)

BASE-TERTIARY EXHUMATION IN THE GRAND BANKS REGION?

Lithostratigraphic chart Jeanne d’Arc Basin

Husky 2015

West Flying Foam L-23

Burial history and VR data. Grand Banks well West Flying Foam L-23

Burial history produced from the lithostratigraphic breakdown obtained from the ‘BASIN Database’. Default thermal history: Maturity profile predicted if all units are at maximum post-depositional temperatures Default thermal history for 25C/km

Burial history and VR data Grand Banks well West Flying Foam L-23

Burial history reconstruction required to explain the GSC VR data Maturity profile (red line) predicted by the burial history reconstruction Profile involving 2 periods of deeper burial Max temps pre-Cret. section Default thermal history for 25C/km

Evidence for vertical movements both prior to and after break- up along the margin of Labrador and Newfoundland

• Pre-Cretaceous denudation, onshore and offshore
• Early Miocene uplift and erosion of Labrador;

prograding wedges offshore

• Late? Miocene exhumation offshore Labrador
• Pliocene uplift and erosion of Labrador;

prograding wedges offshore

• Possibly base-Tertiary exhumation, Grand Banks

Conclusions