*former Ph.D. student;
†postdoctoral research scientist or fellow.
1. Deformation and basin formation along strike-slip faults [download PDF 22.2 MB]
This paper, which is among my most highly cited, was an outgrowth of lectures prepared for Exxon schools in structural analysis and basin tectonics in the early 1980s, and my six years in southern California. It still represents one of the best available summaries of the geological attributes of strike-slip basins. Kevin Biddle, who joined Exxon just two years before I did, remained with the corporation until his retirement in 2014.
Christie-Blick, N., and Biddle, K.T., 1985, Deformation and basin formation along strike-slip faults, in Biddle, K.T., and Christie-Blick, N., eds., Strike-Slip Deformation, Basin Formation, and Sedimentation: Society of Economic Paleontologists and Mineralogists Special Publication No. 37, p. 1-34.
2. Sequence stratigraphy in Proterozoic successions [download PDF 532 KB]
This
paper and two Geological Society of America abstracts published in 1985
represent the first application of sequence stratigraphic principles in
Proterozoic rocks.
Christie-Blick, N., †Grotzinger, J.P., and von der Borch, C.C., 1988, Sequence stratigraphy in Proterozoic successions: Geology, v. 16, p. 100-104.
3. Pre-Mesozoic palinspastic reconstruction of the eastern Great Basin (western United States) [download PDF 2.4 MB]
In
putting together a pre-Mesozoic palinspastic reconstruction for the
eastern Great Basin, we made two simplifying assumptions. One was to
accept the recently published pre-Miocene reconstruction of Wernicke et
al. (1988) for the transect between the Sierra Nevada and Colorado
Plateau at the latitude of Las Vegas. The other was to assume on the
basis of available paleomagnetic data that the Sierra Nevada had
experienced little or no net rotation. Initially presented as a poster
at the Denver Centennial meeting of the Geological Society of America in
1988, the reconstruction attracted a lot of attention. Given what we
have learned over the past few years in the central Basin and Range
Province (e.g., Anders et al., 2006, Journal of Geology, v. 114, p. 645-664; Renik et al., 2008, Journal of Sedimentary Research,
v. 78, p.199-219), it is now our view that the magnitude of late
Cenozoic crustal extension will prove to be appreciably smaller than we
assumed in 1989.
*Levy, M., and Christie-Blick, N., 1989, Pre-Mesozoic palinspastic reconstruction of the eastern Great Basin (western United States): Science, v. 245, p. 1454-1462.
4. Working hypotheses for the origin of the Wonoka canyons (Neoproterozoic), South Australia [download PDF 12 MB]
This
paper focuses on a series of intriguing kilometer-deep incised valleys
of late Neoproterozoic age in the Flinders Ranges of South Australia.
It’s significance is in working through the full range of explanations
permitted by available evidence at that time. Field work completed in
the 1990s, but not yet properly published, reinforced the view that the
canyons were cut subaerially, most likely as a result of the desiccation
of a marine embayment temporarily cut off from the open ocean.
Christie-Blick, N., von der Borch, C.C., DiBona, P.A., 1990, Working hypotheses for the origin of the Wonoka canyons (Neoproterozoic), South Australia: American Journal of Science, v. 290-A (Cloud volume), p. 295-332.
5. Onlap, offlap, and the origin of unconformity-bounded depositional sequences [download PDF 2.4 MB]
This paper is an extension of my 1990 National Academy of Sciences article on the seismic stratigraphic record of sea-level change, and a second attempt to communicate a conclusion that had struck me as self-evident since around 1984, but that is still not widely appreciated or accepted. Unconformities or sequence boundaries develop over a finite interval of geological time, not instantaneously, and they don’t necessarily have anything to do with sea-level change.
Christie-Blick, N., 1991, Onlap, offlap, and the origin of unconformity-bounded depositional sequences: Marine Geology, v. 97, p. 35-56.
6. Tectonic subsidence of the early Paleozoic passive continental margin in eastern California and southern Nevada [download PDF 1.8 MB]
The
significance of this paper is that we investigated the subsidence
history of a Cambro-Ordovician passive continental margin in a region in
which post-rift thermal subsidence can be compared directly with
evidence for crustal extension in underlying Proterozoic rocks. The
mismatch that emerged, and that later work indicates is common at
younger passive margins, is best explained by inhomogeneous extension of
the continental lithosphere. The paper is notable also for quantifying
early Paleozoic eustatic change. Most of what passes for sea-level
change in the Paleozoic literature is a local assessment of changes in
paleowater depth (a different term in the backstripping equation).
Subsequent revision of the Cambrian timescale only amplifies the basic
conclusions, though details could be usefully revisited.
*Levy, M., and Christie-Blick, N., 1991, Tectonic subsidence of the early Paleozoic passive continental margin in eastern California and southern Nevada: Geological Society of America Bulletin, v. 103, p. 1590-1606.
7. Is the Sevier Desert reflection of west-central Utah a normal fault?
The
abundance of healed and partially healed microfractures in quartz
particles recovered from cuttings from two wells in the Sevier Desert is
invariant with depth, contrary to what might be expected above a
detachment fault with several tens of kilometers of displacement. This
paper was very controversial at the time because the existence of a
regional-scale low-angle normal fault had been generally accepted since
the mid-1970s, based upon the interpretation of seismic reflection data.
Not much changed in that regard over the next decade or so, in spite of
a series of papers extending the initial conclusions (e.g., Anders et
al., 2001, Geological Society of America Bulletin, v. 113, p. 895-907; Wills et al., 2005, American Journal of Science, v.
305, p. 42-100; Christie-Blick et al., 2007, Geological Society of
London Special Publication No. 282, p. 419-439). However, strong
community support has emerged for scientific drilling and making in situ
measurements in the Sevier Desert basin, under the auspices of the
International Continental Scientific Drilling Program, to test the
detachment hypothesis and to determine the conditions under which the
fault may have slipped.
Anders, M.H., and Christie-Blick, N., 1994, Is the Sevier Desert reflection of west-central Utah a normal fault?: Geology, v. 22, p. 771-774.
8. Sequence stratigraphy [download PDF 2 MB]
This
paper tends to be cited more frequently than it is read. The intent was
to balance the generally accepted essence of sequence stratigraphy with
an evaluation of practical shortcomings – foremost of which are the
subjective interpretation of systems tracts, and a tendency to ignore
the role of tectonic phenomena, even in sedimentary basins in which
stratal geometry is clearly influenced by deformation. I credit Rex Cole
of Unocal (and now Mesa State College) for drawing my attention to the
absence of detached lowstand sandstones in the late Cretaceous foreland
of eastern Utah and western Colorado – unintentionally providing
critical support for the idea that in most sedimentary basins, incised
valleys are fundamentally highstand rather than lowstand features.
Christie-Blick, N., and *Driscoll, N.W., 1995, Sequence stratigraphy: Annual Review of Earth and Planetary Sciences, v. 23, p. 451-478.
9. Sequence stratigraphy and the interpretation of Neoproterozoic earth history [download PDF 2.3 MB]
This
paper deals with practical issues for the sequence stratigraphic
interpretation of Proterozoic successions, with examples drawn from the
Flinders Ranges of South Australia. It also makes a specific
recommendation for the location of what became the base-Ediacaran Global
Boundary Stratotype Section and Point (GSSP) from the perspective of
sequence stratigraphy (Knoll et al., 2004, Science, v. 305, p. 621-622; Knoll et al., 2006, Lethaia, v. 39, p. 13-30).
Christie-Blick, N., Dyson, I.A., and von der Borch, C.C., 1995, Sequence stratigraphy and the interpretation of Neoproterozoic earth history, in Knoll, A.H., and Walter, M., eds., Neoproterozoic Stratigraphy and Earth History: Precambrian Research, v. 73 (special volume), p. 3-26.
10.
Paleomagnetic polarity reversals in Marinoan (ca. 600 Ma) glacial
deposits of Australia: Implications for the duration of low-latitude
glaciation in Neoproterozoic time [download PDF 1.8 MB]
More
than 40 years after Brian Harland first floated the idea of Proterozoic
equatorial glaciation, Linda Sohl’s paper provided definitive evidence
for the near-depositional age of the low-inclination C component of
magnetization in the glaciogenic Elatina Formation (a positive regional
fold test, and evidence for multiple polarity reversals). Initial data
were first presented to a packed room at the 1995 annual meeting of the
Geological Society of America, and they materially influenced the
development of the snowall Earth hypothesis (P.F. Hoffman et al., 1998, Science,
v. 281, p. 1342-1346). Linda deserves credit for collecting a set of
pilot samples during her first field season in Australia (1993), in
spite of my lukewarm support for tackling a problem that had long
stymied those with considerably more experience in paleomagnetics. That
things worked out was due to a combination of good luck, and dogged
processing of a huge number of samples. Ironically, while the snowball
Earth contributed to a sea change in opinion, from general doubt about
the viability of equatorial glaciation to widespread support for the
idea that the Earth may have remained totally ice-covered for millions
of years under what were effectively super-greenhouse conditions, the
hypothesis failed more or less immediately to withstand scrutiny (e.g.,
Christie-Blick et al., 1999, Science, v. 284, p. 1087; Kennedy et al., 2001, Geology, v. 29, p. 1135-1138).
*†Sohl, L.E., Christie-Blick, N., and Kent, D.V., 1999, Paleomagnetic
polarity reversals in Marinoan (ca. 600 Ma) glacial deposits of
Australia: Implications for the duration of low-latitude glaciation in
Neoproterozoic time: Geological Society of America Bulletin, v. 111, p. 1120-1139.
11.
Are Proterozoic cap carbonates and isotopic excursions a record of gas
hydrate destabilization following Earth's coldest intervals? [download PDF 220 KB]
This
is the first of a series of papers promoting an alternative to the
snowball Earth. Martin Kennedy and I had spent a field season in
Australia in 1995 looking at weird fabrics that he had first noted are
widely developed in cap carbonates (Kennedy, 1996, Journal of Sedimentary Research,
v. 66, p. 1050-1064), and I had become intrigued by Gerry Dickens’s
explanation for the late Paleocene carbon isotope excursion in terms of
the degradation of methane hydrates. We reasoned that methane hydrates
ought to have been extraordinarily abundant on a planet sufficiently
cold to support low-latitude glaciation. So we suggested methane release
as a way to account for diverse evidence for syn-depositional
disruption of the carbonates and, at a global scale, for the marked
negative carbon isotope anomaly with which they are commonly associated.
†Kennedy, M.J., Christie-Blick, N., and *†Sohl, L.E., 2001, Are
Proterozoic cap carbonates and isotopic excursions a record of gas
hydrate destabilization following Earth's coldest intervals?: Geology, v. 29, p. 443-446.
12. Evaluating the stratigraphic response to eustasy from Oligocene strata in New Jersey [download PDF 312 KB]
Sequence
boundaries in the New Jersey Oligocene correspond with eustatic lows,
and condensed sections (intervals of sediment starvation) with eustatic
highs. The conclusion is significant because according to standard
concepts in sequence stratigraphy, for an up-dip location at an old
passive continental margin, where rates of glacially modulated sea-level
change ought to have been as much as an order of magnitude greater than
the rate of subsidence, sequence boundaries would be expected to form
early, as sea level began to fall. The unexpected phase lag corresponds
with almost half a cycle.
†Pekar, S.F., Christie-Blick, N., Kominz, M.A., and Miller, K.G., 2001, Evaluating the stratigraphic response to eustasy from Oligocene strata in New Jersey: Geology, v. 29, p. 55-58.
13. Sequence stratigraphy of the Neoproterozoic Infra Krol Formation and Krol Group, Lesser Himalaya, India [download PDF 1.7 MB]
This
is a particularly nice example of sequence stratigraphic analysis in a
Neoproterozoic succession, with intriguing implications for
chemostratigraphy in old rocks. The paper also departs markedly from
previously published interpretations of Lesser Himalayan stratigraphy
and sedimentology. Regional stratigraphic discontinuities were traced
over a distance of nearly 300 km in an oblique cross-section through the
Krol platform. Three of the surfaces are interpreted as sequence
boundaries on the basis of locally developed incised valleys and
breccia-filled paleokarstic depressions. Inconsistencies in the
stratigraphic location of carbon isotopic minima with respect to
unconformities raise doubts about the interpretation of such data in
isolated sections elsewhere. That it took an additional four years to
publish the details of the geochemical data (Kaufman et al., 2006, Precambrian Research,
v. 147, p. 156-185), with minimal conclusions, reflects a continuing
lack of agreement among the authors with respect to the significance of
those data. A companion paper (Jiang et al., Sedimentology, v. 50, p. 921-952) deals with details of the sedimentology and sedimentary cyclicity.
*Jiang Ganqing, Christie-Blick, N., Kaufman, A.J., Banerjee, D.M., and Rai, V., 2002, Sequence stratigraphy of the Neoproterozoic Infra Krol Formation and Krol Group, Lesser Himalaya, India: Journal of Sedimentary Research, v. 72, p. 524-542.
14. Calibration between eustatic estimates from backstripping and oxygen isotopic records for the Oligocene [download PDF 480 KB]
A
long-standing goal in the quantification of ancient sea-level change
was to merge constraints from passive continental margins with deep-sea
oxygen isotope data. This paper is notable for accomplishing that goal
for the first time, and for deriving the first pre-Pleistocene
calibration between sea-level change and δ18O
(0.10‰-0.13‰/10 m for Oligocene time). The paper also draws attention
to the important difference between eustasy and what we term apparent
sea-level change. In the case of eustasy, the reference frame is the
center of the Earth, or at least a continental interior acting as a
proxy for stability.). As sea level rises and falls eustatically,
flooded portions of the crust undergo water loading or unloading, so
that observed fluctuations in water depth (apparent sea-level change)
exceed the eustatic changes that were responsible by a factor of ~1.48.
The oxygen isotope calibration refers to this larger figure.
†Pekar, S.F., Christie-Blick, N., Kominz, M.A., and Miller, K.G., 2002, Calibration between eustatic estimates from backstripping and oxygen isotopic records for the Oligocene: Geology, v. 30, p. 903-906.
15.
Quantitative constraints on the origin of stratigraphic architecture at
passive continental margins: Oligocene sedimentation in New Jersey,
U.S.A. [download PDF 1.2 MB]
This
article is the last of a series that Steve Pekar and I put together as
an extension of his Ph.D. research at Rutgers University. The unifying
idea for the paper was to evaluate all of the factors governing
Oligocene sedimentation and sequence development at the New Jersey
margin. Among key conclusions: The unexpected correspondence of sequence
boundaries with eustatic minima and the absence of lowstand deposits in
this example relates to an active wave climate that permitted the
efficient transfer of sediment across the shallow shelf, and prevented
the development of point sources. The paper was selected as the
outstanding contribution in the Journal of Sedimentary Research
for 2003. Ironically, given the general significance of the
conclusions, the paper had yet to garner a single literature citation at
the time the award was made two years after publication.
†Pekar, S.F., Christie-Blick, N., Miller, K.G., and Kominz, M.A., 2003, Quantitative
constraints on the origin of stratigraphic architecture at passive
continental margins: Oligocene sedimentation in New Jersey, U.S.A.: Journal of Sedimentary Research, v. 73, p. 227-245.
16. Stable isotopic evidence for methane seeps in Neoproterozoic postglacial cap carbonates [download PDF 564 KB]
An obvious criticism of the methane hydrate hypothesis (Kennedy et al., 2001, Geology,
v. 29, p. 443-446) was the apparent absence of the large local
variations in carbon isotopic composition that might be expected in the
vicinity of cold seeps. Analyses of limestone peloids, clots and
fringing cements in marine tepee-like structures in the Doushantuo cap
carbonate of South China reveal δ13C
values ranging from +5‰ to –41‰. Comparable data have now been obtained
at other locations. Among implications: dolomitization of the cap in
many places may have resulted in partial re-equilibration of isotopic
values, as we had long suspected.
*Jiang Ganqing, †Kennedy, M.J., and Christie-Blick, N., 2003, Stable isotopic evidence for methane seeps in Neoproterozoic postglacial cap carbonates: Nature, v. 426, p. 822-826.
17. A new period for the geologic time scale [download PDF 184 KB]
This paper and two related articles (Knoll et al., 2004, Episodes, v. 27, p. 222; Knoll et al., 2006, Lethaia,
v. 39, p. 13-30) constitute the final product of 16 years of work by
the Subcommission on the Terminal Proterozoic System of the
International Union of Geological Sciences (IUGS). Andy Knoll was the
chair of the subcommission. I was lead proponent (with Martin Kennedy
and Linda Sohl) for one of two proposals for the ultimately successful
location. The Enorama Creek section in the Flinders Ranges, Australia,
and the Nuccaleena post-glacial cap carbonate level in that section,
were endorsed by IUGS in 2004 as a Global Boundary Stratotype Section
and Point (GSSP) formally marking the base of a newly defined system and
the beginning of a period of pre-Cambrian geological time (Ediacaran,
635 to 542 Ma). The same level at nearby Bunyeroo Gorge had been
promoted, unsuccessfully at the time, as the base of a system with the
same name by Preston Cloud and Martin Glaessner (1982, Science,
v. 217, p. 783-792). Cloud, who died in 1991, was a member of my Ph.D.
advisory committee at the University of California, Santa Barbara in the
late 1970s. My own work in Australia began in 1986.
Knoll, A.H., Walter, M.R., Narbonne, G.M., and Christie-Blick, N., 2004, A new period for the geologic time scale: Science, v. 305, p. 621-622.
18. Water shortages, development, and drought in Rockland County, New York [download PDF 11.6 MB]
An
examination of climate data over the past century reveals that the
severity of recent droughts in Rockland County in the suburbs of New
York City is well within the range of past variability. Rather than
climate alone, shortfalls in the domestic water supply, beginning in the
1990s, are due to an increasing mismatch between supply and demand as
the population of the county increased over several decades. The
situation is not likely to improve so long as planning and zoning in the
State of New York remain effectively decoupled from decision-making
with respect to water resources.
Lyon, B., Christie-Blick, N., and Gluzberg, Y., 2005, Water shortages, development, and drought in Rockland County, New York: Journal of American Water Resources Association, December, p. 1457-1469.
19. The Phanerozoic record of global sea-level change [download PDF 568 KB]
A
serious effort to investigate global changes in sea level under the
auspices of the Ocean Drilling Program, and later the Integrated Ocean
Drilling Program, dates back to the Second Conference on Scientific
Ocean Drilling (COSOD II), organized in Strasbourg, France in 1987. This
paper pulls together more than two decades of work by numerous
scientists, including a core group based at Rutgers University and
Lamont-Doherty Earth Observatory. All of the authors except Browning and
Sugarman were associated at one time or another with both institutions.
The main conclusion of the research is that sea-level change was a
primary driver of sedimentary cyclicity for at least the last 34 million
years, with a lesser role in the substantially warmer Cretaceous and
Paleogene periods. Long-term sea level peaked at 100 ± 50 m during the
Cretaceous, implying that ocean-crust production rates were much lower
than previously inferred. The sea-level record is less well established
for Phanerozoic time before about 100 Myr ago.
Miller,
K.G., Kominz, M.A., Browning, J.V., Wright, J.D., Mountain, G.S., Katz,
M.E., Sugarman, P.J., Cramer, B.S., Christie-Blick, N., and Pekar,
S.F., 2005, The Phanerozoic record of global sea-level change: Science, v. 310, p. 1293-1298.
20.
Observations from the Basin and Range Province (western United States)
pertinent to the interpretation of regional detachment faults [download PDF 11.6 MB]
Studies
over several years in three areas of the Basin and Range Province cast
doubt on the interpretation of specific regional detachment faults and
the large extensional strains with which such faults are commonly
associated. The Sevier Desert detachment of west-central Utah is
reinterpreted as an unconformity aligned down dip in some profiles with a
Mesozoic thrust fault, though that view has not
been generally accepted by the structural geological community (see
above). The Mormon Peak detachment of southeastern Nevada is
reinterpreted as the basal contact of a series of Miocene slide blocks
(see Anders et al., 2006, Journal of Geology,
v. 114, p. 645-664). That conclusion is also strongly disputed by those
responsible for the rooted fault interpretation. Re-evaluation of
middle Miocene deposits in eastern California shows that they cannot be
used as a piercing point to constrain large-scale extension and
displacement on detachment faults across the Death Valley region (Renik
et al., 2008, Journal of Sedimentary Research, v. 78, p. 199-219).
Christie-Blick, N., Anders, M.H., Wills, S., Walker, C.D., and *Renik, B., 2007, Observations
from the Basin and Range Province (western United States) pertinent to
the interpretation of regional detachment faults, in Karner, G.D., Manatschal, G., and Pinheiro, L.M., eds., Imaging, Mapping and Modelling Continental Lithosphere Extension and Breakup: Geological Society of London Special Publication No. 282, p. 421-441.
21. Is there a role for sequence stratigraphy in chronostratigraphy? [download PDF 140 KB]
Sequence
stratigraphy provides a useful framework for local or regional
stratigraphic interpretation. However, a lack of consensus on criteria
for recognizing, mapping and hence dating sequence boundaries,
interpretations of uneven quality, and doubts about the universal
eustatic origin and synchrony of unconformity-related sequences limit
the usefulness of sequence stratigraphy in chronostratigraphy.
Christie-Blick, N., †Pekar, S.F., and *Madof, A.S., 2007, Is there a role for sequence stratigraphy in chronostratigraphy?: Stratigraphy, v. 4, No. 2/3, p. 217-229.
22.
Re-evaluation of the middle Miocene Eagle Mountain Formation, and its
significance as a piercing point for the interpretation of extreme
extension across the Death Valley region, California, U.S.A. [download PDF 13.5 MB]
A
sedimentological and stratigraphic re-evaluation of the middle Miocene
Eagle Mountain Formation at Eagle Mountain, California, indicates that
deposition took place in a fluvial-lacustrine setting. The result is
important because the presence of distinctive clasts as large as
boulders derived from the Hunter Mountain batholith of the Cottonwood
Mountains, combined with an alluvial fan interpretation for the
conglomerate in which the clasts are found, has been regarded as
providing definitive, independent support for long-hypothesized,
large-scale crustal extension across the Death Valley region.
*Renik, B., Christie-Blick, N., Troxel, B.W., Wright, L.A., and Niemi, N.A., 2008, Re-evaluation
of the middle Miocene Eagle Mountain Formation and its significance as a
piercing point for the interpretation of extreme extension across the
Death Valley region, California, U.S.A.: Journal of Sedimentary Research, v. 78, p. 199-219.
23. Testing the extensional detachment paradigm: A borehole observatory in the Sevier Desert basin
[download PDF 880 KB]
Low-angle normal faults or detachments are widely regarded as playing an important role in crustal extension and the development of rifted continental margins. However, no consensus exists on how to resolve the mechanical paradox implied by the gentle dips of these faults and by the general absence of evidence for associated seismicity. As part of a new initiative to rationalize geological and geophysical evidence and our theoretical understanding of how rocks deform, a group of forty-seven scientists and drilling experts from five countries met for four days on 15–18 July, 2008 to discuss the present status of the paradox and a borehole-based strategy for resolving it.
Christie-Blick, N., Anders, M.H., Manatschal, G., and Wernicke, B.P., 2009, Testing the extensional detachment paradigm: A borehole observatory in the Sevier Desert basin: Scientific Drilling, No. 8, p. 57-59.
24. Stratigraphic controls on a salt-withdrawal intraslope minibasin,
north-central Green Canyon, Gulf of Mexico: Implications for misinterpreting sea level change
[download PDF 2.2 MB]
3D
seismic reflection data show that sedimentation along the Gulf of
Mexico
continental margin was strongly influenced by salt tectonics, casting
doubt on the role of eustasy in modulating off-shelf "lowstand"
sedimentation, and more generally on the paradigm of reciprocal
sedimentation.
*Madof, A.S., Christie-Blick, N., and Anders, M.H., 2009, Stratigraphic
controls on a salt-withdrawal intraslope minibasin, north-central Green
Canyon, Gulf of Mexico: Implications for misinterpreting sea level
change: American Association of Petroleum Geologists Bulletin, v. 93, p. 535-561.
25. Terminology of geological time: Establishment of a community standard
Consistent
with a convention that has been used widely since the 1970s, this paper
recommends standardization of the distinction between geohistorical
dates (with the symbols ‘a’ for annus, ‘ka’, ‘Ma’ and ‘Ga’ for years and
thousands, millions and billions of years before present) and spans of
geological time (expressed in ‘yr’, ‘kyr’, ‘Myr’ and ‘Gyr’). The
manuscript was rushed into print in the fall of 2009 in an unsuccessful
effort to head off the formal abandonment of this convention by the
International Union of Geological Sciences (IUGS) and the International
Union of Pure and Applied Chemistry (IUPAC) in favor of adopting the
symbols ‘a’, ‘ka’, ‘Ma’ and ‘Ga’ for use in both senses.
Aubry, M.-P., Van Couvering, J.A., Christie-Blick, N., Landing, E., Pratt, B.R.,
Owen, D.E., and Ferrusquía-Villafranca, I., 2009, Terminology of geological time: Establishment of a community standard: Stratigraphy, v. 6, No. 2, p. 100-105.
26. Condensation origin for Neoproterozoic cap carbonates during deglaciation [download PDF 412 KB]
This
paper evolved through multiple drafts (and rejections) since it was
first conceived in 1995. The essence is very simple: Neoproterozoic cap
carbonates represent very slow, and likely episodic sedimentation (over
at least hundreds of thousands of years), not the geologically
instantaneous event popularized by the snowball Earth hypothesis. It is
possible to demonstrate in the Amadeus basin of central Australia how a
classic cap carbonate no more than a few meters thick passes laterally
into a 175-m-thick succession of non-marine conglomerate and sandstone
representing four unconformity-bounded sequences (the Gaylad Sandstone).
Over the 16 years in which the manuscript was in fitful gestation, it
came to be known affectionately as the ‘laughing child’.
Kennedy, M.J., and Christie-Blick, N., 2011, Condensation origin for Neoproterozoic cap carbonates during deglaciation: Geology, v. 39, p. 319-322.
27. Neoproterozoic strata of southeastern Idaho and Utah: record of Cryogenian rifting and glaciation [download PDF 668 KB]
Thirty
years after the publication of Hambrey and Harland’s massive 1981
synthesis of the pre-Pleistocene glacial record, this volume focuses on
substantial progress made in understanding the Neoproterozoic part of
that record. The chapter on Idaho and Utah summarizes important new U/Pb
SHRIMP geochronology on detrital zircons, as well as research on
non-glacial facies, stratigraphy and tectonics undertaken since the
completion of our respective dissertations in 1982 and 1979.
Link, P.K., and Christie-Blick, N., 2011, Neoproterozoic strata of southeastern Idaho and Utah: record of Cryogenian rifting and glaciation, in Arnaud, E., Halverson, G.P., and Shields-Zhou, G., eds., The Geological Record of Neoproterozoic Glaciations: Geological Society, London, Memoirs, v. 36, p. 425-436.
28. Does God exist? Does it matter? [download PDF 340 KB]
This short, peer-reviewed article represents an attempt to stake out a position purposefully on a sensitive topic. After years of mulling, I have come to accept Richard Dawkins’s view: that the distinction between propositions that are testable (subject to the scientific method) and matters of faith (supposedly outside the realm of science) is at best fuzzy. Given that much of what is believed is inconsistent with science and that the rest is so fundamentally anthropocentric that it makes no sense at the length scales and timescales of the universe, as they are now understood, it seems to me not unreasonable to point that out. The manuscript was written in May-June, 2010 for Freethought Today, a monthly newspaper of the Freedom from Religion Foundation, and provisionally accepted at that time. I pulled the plug after one year when no publication date could be confirmed.
Christie-Blick, N., 2011, Does God exist? Does it matter?: American Atheist, v. 49, No. 3, p. 20-21 and 39.
Addendum: A conversation with Christian Chapman [download PDF 300 KB]
Christian
Chapman is an aptly named evangelical Christian, a pastor by training,
and a speaker for the Colorado-based Kingdom Building Ministries. I
wrote to Christian in late December, 2011, after an article appeared in
the New York Times concerning his evangelical work in public
schools. This is the lightly edited text of a conversation that I had
with Christian, via Facebook, from 2-13 May, 2012. The exchange
illuminates how those with sufficiently deep faith justify positions
that are strikingly inconsistent with what has been discovered through
painstaking scientific research; and at least in part why it has proven
so difficult to communicate scientific results to lay people in some
parts of the United States.
29. Geological time conventions and symbols [download PDF 132 KB]
This article was written as a rebuttal of action by the International Union of Geological Sciences (IUGS) and the International Union of Pure and Applied Chemistry (IUPAC) to abandon the longstanding convention in Earth science of distinguishing between geohistorical dates and spans of geological time. The symbols a, ka, Ma, and Ga are recommended for exclusive use for points in geological time 100, 103, 106, and 109 years before present; and yr, kyr, Myr, and Gyr for geohistorical time in years duration (again adopting SI prefixes). Such usage is consistent with current practice of the American Geophysical Union, Geological Society of America, American Association of Petroleum Geologists, etc.
Christie-Blick, N., 2012, Geological time conventions and symbols: GSA Today, v. 22, no. 2, p. 28-29.
30. Cominco American well: Implications for the reconstruction of the Sevier orogen and Basin and Range extension in west-central Utah [download PDF 3.2 MB]
This paper sheds new light on the interpretation of Neoproterozoic and Cambrian stratigraphy and Mesozoic structure in a region that has been influential in the development of ideas about crustal shortening and extension. The Canyon Range thrust is shown to cut the Cominco American well at an appreciably shallower level than generally accepted (e.g., DeCelles and Coogan, 2006, Geological Society of America Bulletin, v. 118, p. 841-864; Coogan and DeCelles, 2007, Geological Society of America Bulletin, v. 119, p. 508-512), and not to provide a piercing point for the estimation of displacement on the Sevier Desert detachment or justification for the existence of the detachment.
Anders, M.H., Christie-Blick, N., and Malinverno, A., 2012, Cominco
American well: Implications for the reconstruction of the Sevier orogen
and Basin and Range extension in west-central Utah: American Journal of Science, v. 312, p. 508-533.
31. Do phreatomagmatic eruptions at Ubehebe Crater (Death Valley, California) relate to a wetter than present hydro-climate? [download PDF 608 KB]
The Ubehebe project was hatched during the 2008 Spring Break trip to Death Valley, in a discussion of why most eruptions at Ubehebe Crater have been phreatomagmatic – steam explosions caused by the interaction of rising magma with groundwater – in one of the most arid places on Earth. Beryllium-10 (10Be) surface exposure dating confirmed that the main and most recent period of activity was between 0.8 and 2.1 ka, a span that encompassed an interval of prolonged drought in the American southwest (the Medieval Warm Period). We conclude on that basis that sufficient groundwater was generally available at the Ubehebe site to trigger phreatomagmatic eruptions, in spite of the prevailing arid conditions. Peri Sasnett prepared the samples during a summer internship at Lamont in 2009, and used the results for her 2011 senior thesis.
Sasnett, P., Goehring, B.M., Christie-Blick, N., and Schaefer, J.M., 2012, Do phreatomagmatic eruptions at Ubehebe Crater (Death Valley, California) relate to a wetter than present hydro-climate?: Geophysical Research Letters, v. 39, L02401, doi:10.1029/2011GL050130.
32. A new hypothesis for the amount and distribution of dextral displacement along the Fish Lake Valley-northern Death Valley-Furnace Creek fault zone, California-Nevada [download PDF 5.5 MB]
The Fish Lake Valley–northern Death Valley–Furnace Creek strike-slip fault zone is the easternmost active element of the San Andreas transform plate boundary, and it provides a key constraint for tectonic reconstructions of the Death Valley area and the central Basin and Range Province. The main contribution of this paper is to show that offset since 13-10 million years ago was no more than ~50 km. This is appreciably less than estimates as high as 80 km obtained by previous authors. Among implications of our result: the increase in line length across Death Valley between points in what are now the Cottonwood Mountains and Nopah Range, and through a combination of extension and strike slip, has been overestimated by a factor of 50%. Displacement along and tilting of discrete normal faults is sufficient to account for the inferred extension. Mechanically problematic mechanisms such as regional-scale detachment faulting and the rolling hinge model aren’t required.
*Renik, B., and Christie-Blick, N., 2013,
A new hypothesis for the amount and distribution of dextral displacement along the Fish Lake Valley-northern Death Valley-Furnace Creek fault zone, California-Nevada: Tectonics, v. 32, p. 123-145, doi:10.1029/2012TC003170.
33. Tectonically controlled nearshore deposition: Cozzette Sandstone, Book Cliffs, Colorado, U.S.A. [download PDF 10.4 MB]
Eustasy remains the generally accepted explanation for sedimentary cyclicity at timescales of < 1 Myr even in tectonically active settings such as the Cretaceous interior seaway (a foreland basin). This paper challenges that view by using a combination of outcrop and downhole log data from 294 gas wells to demonstrate a key role in this basin for brittle deformation and three-dimensional tectonic tilting at length scales of up to 50 km and timescales of ~200 kyr. An innovation in the reported research was to make use of a set of overlapping photographs acquired by helicopter for the entire 40 km panel of the Book Cliffs encompassed by our study. Those photographs and subsurface constraints were critical in establishing subtle stratal geometry (e.g., offlap at parasequence scale) that may be generally present but commonly missed in conventional outcrop work.
*Madof, A.S., Christie-Blick, N., and Anders, M.H., 2015, Tectonically controlled nearshore deposition: Cozzette Sandstone, Book Cliffs, Colorado, U.S.A.: Journal of Sedimentary Research, v. 85, p. 459-488, doi:10.2110/jsr.2015.26.
34. Reexamination of the crustal boundary context of Mesoproterozoic granites in southern Nevada using U-Pb zircon chronology and Nd and Pb isotopic compositions [download PDF 2.1 MB]
New dating of Rapakivi or A-type granites in southern Nevada yields a surprising result: none of the granites we sampled from the supposedly widespread 1,400-1,450 Ma suite is of that age. Most samples cluster in age around 1,680 Ma. One sample, from Gold Butte, Nevada, yielded an age of 1,373 ± 6 Ma. Previously inconsistent mapping of isotopic crustal boundaries is refined and rationalized in the context of the new geochronology to accommodate new and published Nd and Pb isotopic data.
*Almeida, R.V., Cai, Y., Hemming, S.R., Christie-Blick, N., and Neiswanger, L.S., 2016,
Reexamination of the crustal boundary context of Mesoproterozoic granites in southern Nevada using U-Pb zircon chronology and Nd and Pb isotopic compositions: Journal of Geology, v. 124, p. 313-329, doi:10.1086/685766.
35. Unreciprocated sedimentation along a mud-dominated continental margin, Gulf of Mexico, U.S.A.: Implications for sequence stratigraphy in muddy settings devoid of depositional sequences [download PDF 16.5 MB]
According to widely accepted sequence stratigraphic and fill-and-spill models, sedimentary cyclicity at continental margins is modulated by a combination of sea-level change and the filling of pre-existing bathymetric depressions. New work in the Pliocene to Holocene of offshore Louisiana suggests that the distribution of facies, timing and location of mass transport deposits, and rates of sediment accumulation are controlled instead by salt-related subsidence.
*Madof, A.S., Christie-Blick, N., Anders, M.H., and Febo, L.A., 2017,
Unreciprocated sedimentation along a mud-dominated continental margin, Gulf of Mexico, U.S.A.: Implications for sequence stratigraphy in muddy settings devoid of depositional sequences: Marine and Petroleum Geology, v. 80, p. 492-516, doi:10.1016/j.marpetgeo.2016.12.022.