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A Appalachian to great depths at the time of evaporation
based on the general principles of isostasy
chita-Marathon terranes (cf. Karner et al., 2012; Mohn et al., 2015).
Oua For the basin to have remained shallow
Suture? Suwanne ECMA (e.g., Marton and Buffler, 1994; Rowan,
2014), an unknown mechanism would be
? Suture? required. It thus seems more likely that the
evaporites formed significantly below
Yucatan block global base level by drawdown, analo-
gously to the Mediterranean and Red Sea
190 Ma 100 km during the Messinian (7.25–5.83 Ma) crisis
B (e.g., Imbert and Philippe, 2005; Ryan,
2008), with rapid flooding rather than
Callovian evaporite basin rapid basin deepening governing the depo-
sition of the succeeding Smackover
Yucatan Block Formation (e.g., Heydari et al., 1997).
Horbury et al. (2003) describe rapid base-
160 Ma 100 km level changes during the Late Jurassic,
of magnitudes not readily explained by
Figure 3. (A) Pre-opening reconstruction of the magnetic grid, restoring the Houston and Campeche eustatic changes, and attribute these to
magnetic anomalies. Note the alignment of the Appalachian frontal positive anomaly with a linear tectonic forcing. In addition to possible
positive anomaly across Yucatan, suggestive of a good fit and a continuation of the orogen across breaching and rapid influx of water to the
Yucatan. Arrow indicates direction that Yucatan will become pulled with Gondwanaland away from Gulf of Mexico during the Kimmeridgian,
North America. (B) 160 Ma reconstruction marking the transition between the mainly translational the basin-wide Tithonian source rock is a
motion and subsequent pronounced rotation around a rotation pole in the Florida Straits area. candidate for deposition during rapid
ECMA—East Coast magnetic anomaly. influx of sea water into a confined (silled)
basin, possibly analogous to the organic-
GULF OF MEXICO BASIN 2001; Holguín-Quiñones et al., 2005) was rich sediments formed in the confined
CONFINEMENT deposited next. Holocene Black Sea (cf. Arthur and
Sageman, 2004). Given the geometry of
The Gulf of Mexico’s evaporite basin Evaporite deposition over oceanic crust the Gulf of Mexico back-arc basin, it
must represent confinement from the was suggested by Marton and Buffler appears reasonable that tectonic forcing
world’s oceans. The evaporites are mainly (1994) and Imbert and Philippe (2005), and could cause both periodic closing and
halite, and their age is constrained by indirectly implied by the mapping of oce- breaching of marine connections. The
overlying and underlying strata to approxi- anic crust under much of the northern Gulf alternative, rapid whole-scale basin sub­
mately Callovian (e.g., Salvador, 1991; of Mexico by Kneller and Johnson (2011). sidence/uplift or eustatic sea-level changes,
Marton and Buffler, 1994). Overlying the A magma-poor early development of the appears more difficult to explain.
evaporites are eolian sands of the Norphlet Gulf of Mexico (as proposed by e.g.,
Formation, in turn overlain by Kneller and Johnson, 2011; Rowan, 2014) Renewed confinement and drawdown of
Kimmeridgian Smackover carbonate source means that the evaporites must have the Gulf of Mexico has been proposed dur-
rocks, followed by the Buckner Anhydrite. formed on exhumed mantle and/or hyper- ing the Paleocene-Eocene (66.0–33.9 Ma),
The basin-wide marine Tithonian (152.1– extended crust. For all of these models, the related to docking of Cuba and closing off
145.0 Ma) source rock (e.g., Cole et al., basin floor must inevitably have subsided of the Gulf of Mexico’s Atlantic connec-
tion in the Florida Strait (Rosenfeld and
Pindell, 2002). Support for this interpreta-
tion includes major canyon cutting, karsti-
fication, sequence boundaries unrelated to
worldwide eustatic changes, and coal beds
immediately underlain and overlain by
bathyal sediments (Rosenfeld and
Blickwede, 2006; Cossey et al., 2016).

CANADA BASIN CONFINEMENT

The Arctic Ocean (Canada Basin,
Makarov-Podvodnikov Basin, and Eurasia
Basin) was periodically cut off from, or
poorly connected to, the world’s oceans
until the middle Miocene (ca. 17.5 Ma)
opening of the Arctic Gateway along the
Fram Strait (Jakobsson et al., 2007).

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