DISCIPLINES AND INTERESTS:
Sedimentology, stratigraphy, field mapping, petrography,
stable-isotope geochemistry, diagenesis, climate, tectonics, and correlation of Neoproterozoic successions
PEER-REVIEWED IN PRINT (students *)
C.M., Gehrels, Porter, S.M., Heizler, M., G.E., Cox, G., Karlstrom, K.E., Crossey,
L.J., and Timmons,
J.M., submitted 2016. Correlation of the mid-Neoproterozoic Chuar
Group, Uinta Mountain Group, and Pahrump Group (ChUMP strata), western
U.S.: Implications for a changing Earth
System at ca. 740-780 Ma. Geological
Society of America Bulletin. In review.
Strandmann, P.A.P., Stüeken, E.E., Elliott, T., Poulton, S.W., Dehler, C.M.,
Canfield, D.E. and Catling, D.C., 2015. Selenium isotope evidence for
progressive oxidation of the Neoproterozoic biosphere. Nature communications, 6. pdf
C.M., 2014. Advances in Neoproterozoic
biostratigraphy spark new correlations and insight into evolution of life:
Geology, v. 42, no. 8, p. 731-732. pdf
R.C., Dehler, C. M., Karlstrom, K.E., Link, P.K., Gehrels, G.E., 2014,
Geochronologic and stratigraphic constraints on the Mesoproterozoic and
Neoproterozoic Pahrump Group, Death Valley, CA: A record of the assembly,
stability and breakup of Rodinia: GSA Bulletin, v. 126, no. 5-6, p. 652-664. pdf
W.A., Dehler, C.M., Link, P.K., *Balgord, E.A., *Keeley, J., *Hayes, D.S.,
Fanning, C.M., Wells, M.L., and
Johnston, S.M.. 2014. Tectono-stratigraphic framework of Neoproterozoic to
Cambrian strata, west-central U.S.: Protracted rifting, glaciation, and
evolution of the North American Cordilleran margin: Earth Science Reviews, v.
136, p. 59-95. pdf
R.C., Dehler, C.M., Link, P.K., Karlstrom, K.E., Gehrels, G.G., 2014, Detrital zircon provenance and paleogeography
of the Pahrump Group and overlying strata, Death Valley, California. Precambrian Research, v. 251, p. 102-117. pdf
E.M., *Osterhaut, S. L., Link, P.K., and Dehler, C.M., 2013. Sequence stratigraphy and formalization of
the middle Uinta Mountain Group (Neoproterozoic), central Uinta Mountains,
Utah: A closer look at the western
Laurentian Seaway at ca. 750 Ma. Precambrian
Research, 236 (2013) 65–84. pdf
C.M., Porter, S.M., and Timmons, J.M., 2012.
The Neoproterozoic Earth system revealed from the Chuar Group of Grand
Canyon in Timmons, J.M. and Karlstrom, K.E., eds., Grand Canyon Geology: Two Billion Years of Earth’s History: Geological Society of America Special Paper
489, p. 49-72. pdf
C.M., Anderson, K., and Nagy, R., 2011, New descriptions of the cap dolostone
and associated strata, Neoproterozoic Pocatello Formation, southeastern Idaho,
U.S.A., in Evans, J.P., and Lee, J., eds., Geologic Field Trips to the Basin
and Range, Rocky Mountains, Snake River Plain, and Terranes of the U.S.
Cordillera: Geological Society of
America Field Guide 21, p. 181–192, doi:10.1130/2011.0021(08). pdf
C.M., Fanning, C.M., Link, P.K., Kingsbury, E., Rybczynski, D., 2010. Maximum depositional
age and provenance of the Uinta Mountain Group and Big Cottonwood Formation,
northern Utah: Paleogeography of rifting
western Laurentia. Geological Society of
America Bulletin, ahead of print doi: 10.1130/B30094,
p. 1686-1699. pdf
D.T., Poulton, S., Dehler, C.M., Porter, S.M., Husson, J., Canfield, D., Knoll,
A.K., 2010. An emerging picture of
Neoproterozoic ocean chemistry: Insights
from the Chuar Group, Grand Canyon, U.S.A.
Earth and Planetary Science Letters, v. 290, p. 64-73. pdf
R., Porter, S., Dehler, C.M., Shen, Y., 2009.
Biotic turnover driven by eutrophication before
low-latitude glaciation. Nature
Geoscience, Letters, v. 2, p. 415-418. pdf
B.L., Dehler, C.M., Neff, H., Nelson, S.T. and Eggett, D., 2008. Pilot study experiments in sourcing quartzite,
Gunnison basin, Colorado. Geoarcheology,
Vol. 23, No. 6, 742-778. pdf
B.L., Neff, H., Nelson, S.T., Dehler, C.M., 2008. AD-ICP-MS vs. LA-ICP-MS analysis of quartzite sources,
Gunnison basin Colorado. Current Research
in the Pleistocene, v. 24, p. 133-136. pdf
C.M., Porter, S.M., De Grey, L.D., Sprinkel, D.A., Brehm, A., 2007, The Neoproterozoic Uinta Mountain Group revisited: A synthesis of recent work on the Red Pine
Shale and related undivided clastic strata, Northeastern Utah: in Link, P.K.,
and Lewis, R.S., eds., Proterozoic Geology of western North America and
Siberia, Society of Sedimentary Geology Special Publication 86, p. 151-166. pdf
B. L. and Dehler, C.M., 2006. Sourcing quartzite from the Early Holocene Chance
Gulch Site, Gunnison basin, Colorado. Current Research in the Pleistocene, v.
23, p. 1-3. pfg
C.M., Elrick, M.E., Bloch, J.D., Karlstrom, K.E., Crossey, L.J., DesMarais, D.,
2005. High-resolution δ13C stratigraphy
of the Chuar Group (~770-742 Ma), Grand Canyon:
Implications for mid-Neoproterozoic climate change, Geological Society
of America Bulletin, v. 117, no. 1/2, p. 32-45. pdf
C.M., Elrick, M.E., Karlstrom, K.E., Smith, G.A., Crossey, L.J., Timmons, J.M.,
2001. Neoproterozoic Chuar Group
(~800-742 Ma), Grand Canyon: A record of
cyclic marine deposition during global cooling and supercontinent rifting. Sedimentary Geology, v. 141-142, p. 465-499. pdf
K.E., Bowring, S. A., Dehler, C.M., Knoll, A.H., DesMarais, D.J., Weil, A.B.,
Sharp, Z.D., Geissman, J.W., Elrick, M.B., Timmons, M.J., Crossey, L.J.,
Davidek, K.L., 2000. Chuar Group of the
Grand Canyon: Record of breakup of
Rodinia, associated change in the global carbon cycle, and ecosystem expansion
by 740 Ma. Geology, v. 28, no. 7, p.
J.M., Karlstrom, K.E., Dehler, C.M., Geissman, J.W., Heizler, M.T., 2001. Proterozoic multistage (~1.1 and ~8.0 Ga)
extension in the Grand Canyon Supergroup and establishment of northwest and
north-south tectonic grains in the southwestern United States. Geological Society of America Bulletin, v.
113, no. 2, p. 163-180. pdf
ANDY BREHM--PETROLEUM GEOLOGIST, ANADARKO, DENVER, COLORADO
CAROLINE MYER BREHM--PETROLEUM GEOLOGIST, ANADARKO, DENVER, COLORADO
DAN RYBCZYNSKI--PETROLEUM GEOLOGIST, SOUTHWESTERN ENERGY, SPRING, TEXAS
ESTHER KINGSBURY--PRECAMBRIAN GEOLOGIST, WISCONSIN GEOLOGICAL SURVEY, MADISON, WISCONSIN
SHANNON OSTERHAUT--GEOLOGIST, PIONEER NATURAL RESOURCES, DALLAS/FORTWORTH, TEXAS
DAWN HAYES--PETROLEUM GEOLOGIST, ANADARKO, HOUSTON, TEXAS
ABIGAIL BULLARD (MS)--Testing the ChUMP hypothesis with ID-TIMS
ERIN LATHROP (MS)--The Mesoproterozoic carbon cycle as recorded in the 1.252 Ma Bass Formation, Grand Canyon
WESTON MARTIN (MS) Subsurface and source rock analysis of the Chuar and Uinta Mountain groups of the southwestern US
KATHERINE PAUKERT (MS) C-isotope stratigraphy of the Visingso Group, southern Sweden
MIKAELA PULSIPHER (BS) Detrital zircon geochronology of the VIsingso Group, southern Sweden
FALLON ROWE (BS) Detrital zircon geochronology of the VIsingso Group, southern Sweden
NEOPROTEROZOIC WESTERN U.S.
Jaking the Red Castle Formation, High Uintas (left). Carrying
samples out of the Uintas with help from Thomas and Sonny the llamas.
Kings Peak, highest peak in Utah, on skyline (right).
NEOPROTEROZOIC UINTA MOUNTAIN GROUP, UTAH AND COLORADO
Uinta Mountain Group(UMG) is an amazingly understudied, 4-7
km thick succession of newly dated Proterozoic
strata. U-Pb analyses on detrital zircons has revealed a maximum
depositional age of 766 Ma (Fanning and Dehler, 2005). Therefore, the
to other dated Neoproterozoic successions in the western U.S. such as
the Chuar Group.
Ongoing research in the western Uintas is focused on the Red Pine
organic-rich shale sequence (TOC)>6%). These rocks are
to chemostratigraphic analyses (on organic carbon) and a detailed C-isotope
curve has been generated for about 1000 m of this unit. More
stratigraphic and sedimentologic studies are also underway --this unit
not been thoroughly described and paleoenvironmental interpretations
controversial. Correlative(?) strata on the eastern side of the
are very different and we (me and students) hypothesize that the UMG in
this area represents 4-7000 m of braided stream and marginal marine
Mapping in the eastern UMG by students has resulted the
subdivision into formations, and sequence stratigraphic
principles may be applicable. We also hypothesize (me and Doug
from the UGS) that the eastern UMG correlates with the units to the
(e.g., Red Pine Shale), but years of mapping will be necessary to test
this. Strata in the Kings Peak area in the central part of the
range is amenable to sequence stratigraphy and will help to test this
Photo to left: Typical outcrop of the eastern UMG (braided stream deposits). Bushes are ~ 1 m tall.
Photo to right: Interbedded organic-rich shales and cross-bedded
sandstones of the Red Pine Shale, central Uinta Mountains. Susannah
Porter for scale.
Photo below: Facies change in the Jesse Ewing Canyon Formation:
Neoproterozoic fan delta complex!
Laura DeGrey for scale.
Photomicrograph to right (2.5X): Typical
quartz arenite in the eastern Uinta Mountain Group.
That's right, much of this Precambrian unit is NOT quartzite, but simply a well cemented sandstone.
Above: Dan Rybczynski in his map area near the type section of the new 'formation of Outlaw Trail', northeastern Utah
CHUAR GROUP--NEOPROTEROZOIC RECORD OF THE GRAND CANYON AREA
Conclusions of this work reveal
C-isotope shifts in organic and carbonate carbon. These shifts
with lithostratigraphic and shale geochemical data and the combined
datasets (see below) suggest that climate control was a player for the
This is significant when considering the age of the Chuar Group
Ma) and how it may be coeval or precursory to global-scale
See Karlstrom et al, 2000, Porter and Knoll, 2000; Dehler et al, 2001;
et al., 2001, Dehler et al., 2005; Dehler et al., 2012 for more information. Research on this amazing unit continues.
Figure to left: Multiple datasets collectively
indicate climate as a control on the carbon cycle in the
mid-Neoproterozoic (see Dehler et al., 2005, GSAB)
Photo to right: The Jupiter and Carbon Canyon members of
the Chuar Group, ~400 m in view.
Photo to left: The "brain bed"--complex stromatolites often
referred to as Baicalia or Boxonia. Note the intimate
relationship with variegated siliclastic shale. These microbial
buildups likely grew when climate was dryer and sea level was
relatively lower (and there was more glacial ice on the planet).
See Dehler et al., 2001 for reasoning..
Photo to right: Meter-scale
cycles in the Carbon Canyon Member of the Chuar Group,
be glacioeustatic. See Dehler et al., 2001.
Photo to left: The Sixtymile Formation unconformably
overlies the Chuar Group.
At least the upper part of this unit is now known to be Cambrian!
PAHRUMP GROUP--NEOPROTEROZOIC RECORD OF THE EASTERN MOJAVE DESERT
Got a sample! Is this the same one I sampled before and it is actually Tertiary?
ChUMP HYPOTHESIS (Chuar-Uinta Mountain-Pahrump groups).
idea has been proposed by many workers. Recent detailed work on
all three of these successions will allow testing the idea that the
Chuar, Uinta Mountain, and Pahrump groups, are, atleast in part,
correlative and were part of a western Interior Seaway in the
Neoproterozoic. (George Gehrels, Susannah Porter, Karl Karlstrom, Matt
Heizler, Alan Rooney, Mike Timmons, Laura Crossey, Grant Cox)
projects focus on mid- to late Neoproterozoic strata and their
implications for global paleoclimate, regional tectonics, ocean
geochemistry, and correlation.
Taking the ChUMP hypothesis to another paleocontinent. Study of the
Neoproterozoic Visingso Group in southern Sweden. We have collected
preliminary stratigraphic, stratigraphic, and paleontological samples
towards characterizing this poorly understood unit. (with Susannah
Porter, Alex Zumberg, Alan Rooney, Noah Planavsky, student Katherine
Correlation of mid- to late Proterozoic deposits in Utah and Idaho.
The goal here is to answer questions about
the style and timing of the rifting of the western Laurentian margin.
This project will also address the timing and style of
glaciations during this time, and test the snowball Earth hypothesis.
In this picture (looking west on Antelope Island into the Great Salt Lake) we are all sitting on the same dropstone
within the Mineral Fork Formation.
Paleoecology and the carbon cycle prior to the Sturtian glaciation.
Susannah Porter and I are looking at fossil and stratigraphic
data from mid-Neoproterozoic units to try and understand the cause(s)
for ensuing low-latitude glaciations.
microfossil from the middle Neoproterozoic Horse Thief Springs Fm,
Kingston Range, CA.
The geologic community is optimistic about using
this group of microfossils (thought to be testate amoebae)
as not only
an environmental indicator, but also an index fossil for ca. 750 Ma.
Detrital zircon geochronology of the southern Congo Margin from ca. 800
Ma to ca. 500 Ma. We have collected and run samples to
characterize the rift history of Rodinia and the almalgamation of the
Gondwana. (with Mary Hubbard and Dave Foster).
Watch out for the camelthorn!
and paleontology of the Geertsen Fm and overlying units. (with Mike
Strange and Steve Reynolds), northern UT.
Above: Return from Capitol Reef...time travel complete.
GEO2500 GEOLOGIC EXCURSIONS
GEO3200 EARTH THROUGH TIME
GEO4900 FIELD CAMP
GEO5400/6400 FACIES ANALYSIS
GEO6450/7450 DEEP TIME
Other courses taught: Field Methods, Earth Systems Science, Physical Geology, Sedimentology and Stratigraphy, Advanced General Geology
(graduate-level), Tectonics and Sedimentation (graduate-level)