|Title||A late rift to post-rift shoreline clinoform and shelf-edge model for the offshore Labrador margin, Canada|
|Author||Dafoe, L T; Dickie, K; Williams, G L; Keen, C E|
|Source||5th Atlantic Conjugate Margins Conference, abstract volume; 2017 p. 1|
|Alt Series||Natural Resources Canada, Contribution Series 20170240|
|Meeting||5th Atlantic Conjugate Margins Conference; Porto de Galinhas, Pernambuco; BR; August 23-25, 2017|
|Province||Eastern offshore region|
|Subjects||structural geology; stratigraphy; surficial geology/geomorphology; rifts; rifting; shorelines; seismic reflection surveys; biostratigraphy; sandstones; subsidence; transgressions; Labrador Sea; Baffin
Bay; Hopedale Basin; Markland Formation; Orphan Basin; Cretaceous|
|Program||Baffin Petroleum Systems, GEM2: Geo-mapping for Energy and Minerals|
|Abstract||The Labrador Sea and Baffin Bay evolved through extension between North America and Greenland commencing in the Early Cretaceous, with seafloor spreading beginning by Chron 27 time (Selandian). During
the late-rift to post-rift phase of the Late Cretaceous through Cenozoic, the succession along the Labrador margin can be linked to margin subsidence, global sea level fluctuations, and more localized factors.|
In the Hopedale Basin on the southern
Labrador margin, we have mapped Late Cretaceous and Cenozoic shoreline clinoforms and shelf-edge breaks by integrating our revised paleoenvironmental and biostratigraphic analyses with the seismic reflection interpretation. The
Coniacian-Maastrichtian shoreline clinoform sandstones and correlative deep-water shales of the Markland Formation reflect sag-basin subsidence. The overlying Gudrid Formation represents a major Selandian to basal Ypresian regression. During ensuing
subsidence and transgression, sea level stillstand formed a lower Ypresian shoreline clinoform near the basement hinge. Renewed progradation was initially slow, but was followed by Bartonian regression and formation of subdued Leif Member (Kenamu
Formation) shoreline clinoforms and the earliest true shelf-edge break.
Middle to late Bartonian transgression marks the base of the Mokami Formation, and was followed by progradation and aggradation of a thick upper Bartonian to Rupelian
succession with minor intervening transgressions. Prominent mid-Oligocene and mid-Miocene regressions formed two Saglek Formation shelf-edge deltas with an intervening transgression. Following transgression of the second clinoform and deposition of
an aggradational wedge, Pleistocene glaciation produced the youngest shelf-edge clinoform.
Understanding transgressive-regressive cycles along the Labrador margin provides a predictive model for the stratigraphy of adjacent and conjugate margins
where data is more limited, such as Orphan Basin to the south and the Baffin Bay margin to the north.
|Summary||(Plain Language Summary, not published)|
Basins offshore of Labrador and Baffin Bay share a similar formation history as the Labrador Sea formed during rifting between North America and
Greenland. The early stage of this process resulted in faulting and the development of graben structures that allowed for non-marine and shallow marine sediments to accumulate. However, as rifting moved offshore, the latest Cretaceous and Cenozoic
sections are primarily influenced by global sea level fluctuations. Here we show that transgressive-regressive cycles can be described and mapped regionally along the Labrador margin. We map the presence of shoreline clinoform breaks and shelf-edge
breaks through time and correlate these intervals to other adjacent and conjugate margins in the Labrador Sea-Baffin Bay region.