Prospectus 2021 - CSL Center for Carbonate Research - Comparative Sedimentology Laboratory
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CSL
Center for
Carbonate
Research
and Education
Prospectus
2021
UNIVERSITY OF MIAMI
ROSENSTIEL
SCHOOL of MARINE &
ATMOSPHERIC SCIENCE
CENTER FOR CARBONATE RESEARCH
TABLE OF CONTENTS
Mission of the CSL – Center for Carbonate Research .................................. iii
Knowledge Transfer ................................................................................... iii
Personnel .................................................................................................... v
2021 Research Focus ................................................................................ vii
2021 Planned Projects ............................................................................... ix
2021 Reporting:
Mid-Year Progress Report, Annual Review Meeting and Field Seminars ....................... xi
Education
Certificate Program:
Applied Carbonate Geology ................................................................................ xiii
Research Project Descriptions
Deep-Water Carbonates
Marine Carbonate Sedimentation in an Active Rift Basin
(Red Sea – Gulf of Aqaba)
Sam Purkis and Paul (Mitch) Harris ......................................................................15
Carbonate Contourite Drift Systems
Gregor P. Eberli, Sara Bashah and Ralf J. Weger ....................................................17
The Relationship Between Carbonate Slopes and Contour
Currents
Sara Bashah and Gregor P. Eberli ........................................................................19
Towards a Depositional Model of Coarse-Grained Delta Drift
Deposits, Maiella, Italy - Year 2
Gregor P. Eberli, Mark Grasmueck, and Ralf J. Weger .............................................21
Petrophysics of Carbonate Drifts
Ralf J. Weger, Gregor P. Eberli and Greta Mackenzie ..............................................23
Shallow-Water Carbonates
Seismic Facies and Stratigraphy of the Yucatan Platform
Elizabeth Guzman and Gregor P. Eberli.................................................................25
Evolution of a Modern Ooid Sand Island - South Joulter Cay,
Great Bahama Bank
Juan Carlos Laya, Paul (Mitch) Harris, and Miles Frazer ...........................................27
Sediment Transport on The Great Bahama Bank - Insights
from Fair- & Storm-Weather Conditions
Cecilia Lopez-Gamundi, Brian Barnes, Thomas Dobbelaere, Emmanuel Hanert,
Paul (Mitch) Harris, and Sam Purkis .....................................................................29
Permeability Variations in Cross-Stratified Oolitic Grainstones
(Late Pleistocene Miami Oolite)
Donald F. McNeill ..............................................................................................31
i
Carbonate Sequence Stratigraphy
Carbonate Sequence Stratigraphy in Light of
“Standardized Sequence Stratigraphy”
Gregor P. Eberli ................................................................................................35
The Geochemical Expression of Sequence Boundaries
Peter K. Swart, Greta J. Mackenzie, Amel Saied, Amanda M. Oehlert, and
Gregor P. Eberli ................................................................................................37
Geochemistry
A Global Diagenetic Signal?
Megan Smith, Colleen Brown, Evan Moore, Peter K. Swart, and
Amanda M. Oehlert ...........................................................................................39
Boron, Sulfur, and Clumped Isotopes as Diagenetic
Indicators
Evan Moore, Megan Smith, Sean Murray, and Peter K.
Swart ..............................................................................................................41
Evaluating Drivers of Reefal Transitions Over ~16Myr,
Enewetak Atoll
Colleen Brown, Megan Smith, Peter K. Swart, and
Amanda M. Oehlert ...........................................................................................43
Application of the Δ48 Proxy to the Real World
Peter K. Swart and Chaojin Lu ............................................................................45
Petrophysics
Early Marine Cementation Processes and Velocity Evolution
Mara R. Diaz, Ralf J. Weger, Peter K. Swart, and Gregor P.
Eberli ..............................................................................................................47
Decoding Subtle Diagenetic Alteration: Combining
Geochemical and Petrophysical Approaches
Amanda M. Oehlert, Peter K. Swart, Ralf J. Weger, and Gregor P.
Eberli ..............................................................................................................49
Detecting Pore Types Using Velocity and Resistivity
Ralf J. Weger and Gregor P. Eberli .......................................................................51
Unconventional Reservoirs
Characterization of The Agrio Formation, Neuquén Basin,
Argentina
Ralf J. Weger, Peter K. Swart, and Gregor P. Eberli ................................................53
Virtual Field Trip to the Vaca Muerta Formation, Argentina
Ralf J. Weger, Arthur C.R. Gleason, and Gregor P. Eberli.........................................55
Searching for Elemental Signatures of Sweet Spots in the
Vaca Muerta Formation
Amanda M. Oehlert, Ralf J. Weger, Gregor P. Eberli, and Laura
Rueda .............................................................................................................57
Enhanced Outcrop to Subsurface Correlation in the
Vaca Muerta Formation
Taury Smith, Ralf J. Weger, and Gregor P. Eberli ...................................................59
ii
MISSION OF THE CSL – CENTER FOR CARBONATE RESEARCH
The mission of the CSL – Center for Carbonate Research is to conduct
fundamental research in carbonates for improved reservoir
prediction and characterization.
Our research program is designed to cover four major areas of carbonate geology using and
exploring new techniques in a variety of emerging topics. In addition to the fundamental
knowledge gained from these studies we aim to inform our industrial associates regarding the
newest research techniques that potentially can be incorporated into the workflow of projects
or help to solve longstanding problems in exploration and production.
The projects integrate geology, geophysics, geo-microbiology, and geochemistry and
combine observational, laboratory, and theoretical research, covering four areas:
Modern and Ancient Carbonate Systems
Petrophysics and Near-Surface Geophysics
Unconventional Reservoirs
Geochemistry and Geo-Microbiology of Carbonates
Performing research within these four general research disciplines allows us to address
fundamental questions in carbonate research in a comprehensive way. As a consequence,
some of the research projects are interdisciplinary while others are designed to advance
knowledge in one specific area. The various projects are described in detail in this prospectus
and are retrievable on the website www.cslmiami.info.
KNOWLEDGE TRANSFER
The CSL – Center for Carbonate Research transfers the research
results to our industry partners through an annual meeting, our
website, and publications.
We offer field seminars and in-house short courses.
A Certificate Program in “Applied Carbonate Geology” gives
geoscientists the opportunity to become experts in carbonates.
We present the research results described in the prospectus at the Annual Review Meeting
and provide each company with a digital version of our presentations and publications
stemming from CSL sponsored research. On our website, research results from previous
years can be viewed in the archive section, providing a comprehensive database for many
topics and geographic areas. Upon request, we also share original data sets with participating
companies. Also on request, we offer webinars of various aspects of our research to our
Industrial Associates.
iii
PERSONNEL
PRINCIPAL INVESTIGATORS
Gregor P. Eberli Professor, Seismic Stratigraphy
Sam Purkis Professor, Sedimentology
Peter K. Swart Professor, Geochemistry
James S. Klaus Associate Professor, Paleontology
Amanda M. Oehlert Assistant Professor, Geochemistry
Donald F. McNeill Scientist, Sedimentology, Stratigraphy
Mara R. Diaz Scientist, Geobiology
Ralf J. Weger Scientist, Petrophysics and Unconventional
Greta J. Mackenzie Associate Scientist, Petrography
Mark Grasmueck Adjunct Professor, Subsurface Imaging
Paul (Mitch) Harris Adjunct Professor, Applied Sedimentology
STUDENTS
Sara Bashah, Colleen Brown, Anna H. Ling, Cecilia Lopez-Gamundi, Evan W. Moore,
Megan Smith, Lisa Tanh
POSTDOCTORAL RESEARCHERS
Elizabeth Guzmán
Chaojin Lu
RESEARCH ASSOCIATE
Amel Saied
SCIENTIFIC COLLABORATORS
Christian Betzler, Thomas Lüdmann University of Hamburg, Germany
Emmanuel Hanert Universite Catholique du Louvain, Belgium
G. Michael Grammer Oklahoma State University
Langhorne Bullit “Taury” Smith Smith Stratigraphics, New Orleans
Leticia Rodriguez Blanco Consultant, Buenos Aires, Argentina
Sean Murray Macquarie University, Sydney, Australia
v
2021 RESEARCH FOCUS
The pandemic of 2020 disrupted our planned fieldwork in the Maiella (Italy) platform and
the research expedition to the Mozambique Channel. However, OceanX ‘Deep Blue’ research
cruise was completed in the Fall of 2020 in the northern Red Sea. The goal of the expedition
was to capture the diversity in styles of deposition in an active rift basin. A wealth of
geophysical data was collected and ground-truthed by >400 hours of ROV and submersible
dives. Sediment and water samples complement this comprehensive dataset. This project and
the study of carbonate contourite systems are the focus of the deep-water carbonate
research. Three projects are planned for carbonate contourite systems. First, we continue to
expand our database on the dimensions, composition, and petrophysical properties of
carbonate drifts in different tectonic settings and times. Seismic and core data from the Ocean
Drilling Program will be used to examine the formative role of ocean currents on the flanks of
carbonate platforms. Fieldwork on the Maiella drift delta will investigate the processes forming
coarse-grained current deposits. The overall goal of these studies is to complement the
models of carbonate deep-water deposition that has concentrated on gravity flows. These
sedimentologic and petrophysical models are expected to help de-risk deep-water plays.
The shallow-water carbonate projects examine the small- and large-scale evolution of
carbonate systems. One project uses seismic and well data to unravel the tectonic and
stratigraphic evolution of the Yucatan Platform, influenced by regional Caribbean tectonics,
sea-level controlled infill of a platform interior trough, as well as the Yucatan Current, at least
in the Neogene portion. The analysis of heterogeneity on a reservoir scale is the subject of a
project that examines the evolution of a modern ooid sand island at Joulter Cays (Bahamas).
The influence of diagenesis on petrophysical properties is investigated in two projects. One
evaluates the influence of early, pre-burial meteoric diagenesis on the flow properties of ooid
grainstones with whole-core constant-head hydraulic conductivity measurements on cores of
cross-stratified Miami Oolite. The other project compares the influence of biologically-
mediated versus inorganic-precipitated cements on acoustic velocity and rock strength of ooid
grainstones.
In recent years, two new methods (accommodation succession and stratigraphic surface
methods) have been proposed for conducting sequence stratigraphy in siliciclastic systems.
Applying these methods in carbonate sequence stratigraphy has been a challenge,
because some of the underlying assumptions in these methods are hard to reconcile with
processes in carbonates. A large initiative within the carbonate community is underway to
evaluate these new methods in carbonates. Two projects at the CSL are part of this effort.
One interrogates seismic and outcrop data to assess where surfaces relevant for sequence
stratigraphy fall in a base-level cycle in carbonates. We compare these results to the surfaces
proposed in siliciclastic sequence-stratigraphic models. A second project examines the
geochemical expression of sequence boundaries.
The geochemistry projects focus on two main themes. One compares various isotopic
patterns in the Pacific and Atlantic to assess if diagenetic events, in particular meteoric
diagenetic overprint from sea-level falls, produce global shifts in δ13C and δ18O values that
have traditionally been explained by changes in ocean chemistry. The method of rolling
window regression (RWR) will help to identify types of diagenetic processes and the presence
of global patterns in δ13C and δ18O values. In addition, boron, sulfur, and clumped isotopes
will be used to discriminate between marine and meteoric diagenesis. The second main focus
in geochemistry is the refinement of the clumped isotope method 47). The clumped
isotope value can be used as a temperature proxy, but some carbonate secreting organisms
precipitate calcium carbonate out of equilibrium, making an accurate temperature estimate
uncertain. Incorporating the clumped isotope with mass 48 can help to eliminate any
vii
uncertainty. The stable isotope laboratory within the CSL has established the calibration of this clumped isotope for carbonates precipitated at nine temperatures (5 to 73oC) and reacted at 90oC in a common acid bath. This calibration allows us to investigate the Δ48 values in a number of systems which exhibit non-equilibrium precipitation behavior as regards their Δ47 values. For many years we have explored the control pore structures have on the petrophysical properties of carbonates. Our large database of velocity and resistivity measurements gives us the opportunity to assess how accurately one can discriminate connected interparticle- from separated-moldic porosity using these two petrophysical properties. This year, however, our research in petrophysics includes an examination of the influence of diagenesis on petrophysical properties. The reason for this inclusion is that diagenetic processes have a strong control on both the pore structure, but also on frame stiffness. In two projects we evaluate the different response of early microbial-induced marine cements versus meteoric cements on velocity and permeability, respectively. The effects of multiple diagenetic events on velocity and resistivity on shallow and deep-water carbonates is assessed in a project using the cores and logs along the Bahamas Transect. In the last ten years, we have conducted multi-disciplinary research in the unconventional reservoirs in the Neuquén Basin, focusing on the Vaca Muerta-Quintuco system. We have assembled a comprehensive database and plan to write a field guidebook that summarizes our outcrop results. In conjunction with this effort, we prepare a virtual fieldtrip that will give scientists the opportunity to visit the outcrops of the Vaca Muerta Formation in an “Interactive Multiuser Virtual Reality” environment. With the outcrop work in the Vaca Muerta basically completed, we start to compare and correlate our results to the subsurface. For example, we evaluate the similarities and differences of compositional variations in sequences and cycles in outcrop and in the subsurface with a semi-quantitative analysis of thin section of our measured sections. We also seek to get additional subsurface data for such comparisons. We embark in a new direction in the basin by focusing on the Agrio Formation that contains the marine strata above the Mulichinco Formation and also has high TOC. We plan to acquire a dataset with the same detail and methodology as we did in the Vaca Muerta Formation to characterize the facies, TOC distribution, geochemical signature, and petrophysical properties of this formation. Below we provide a list and the detailed description of each project planned for 2021. viii
2021 PLANNED PROJECTS
DEEP AND SHALLOW -WATER CARBONATES
Marine Carbonate Sedimentation in an Active Rift Basin (Red Sea – Gulf of Aqaba)
Carbonate Contourite Drift Systems
The Relationship Between Carbonate Slopes and Contour Currents
Towards a Depositional Model of Coarse-Grained Delta Drift Deposits, Maiella, Italy
- Year 2
Petrophysics of Carbonate Drifts
Seismic Facies and Stratigraphy of the Yucatan Platform
Evolution of a Modern Ooid Sand Island - South Joulter Cay, Great Bahama Bank
Permeability Variations in Cross-Stratified Oolitic Grainstones (Late Pleistocene
Miami Oolite)
CARBONATE SEQUENCE STRATIGRAPHY
Carbonate Sequence Stratigraphy in Light of “Standardized Sequence
Stratigraphy”
The Geochemical Expression of Sequence Boundaries
GEOCHEMISTRY
A Global Diagenetic Signal?
Boron, Sulfur, and Clumped Isotopes as Diagenetic Indicators
Evaluating Drivers of Reefal Transitions Over ~16Myr, Enewetak Atoll
Application of the Δ48 Proxy to the Real World
PETROPHYSICS
Early Marine Cementation Processes and Velocity Evolution
Decoding Subtle Diagenetic Alteration: Combining Geochemical and Petrophysical
Approaches
Detecting Pore Types Using Velocity and Resistivity
UNCONVENTIONAL RESERVOIRS
Characterization of The Agrio Formation, Neuquén Basin, Argentina
Virtual Field Trip to the Vaca Muerta Formation, Argentina
Enhanced Outcrop to Subsurface Correlation in the Vaca Muerta Formation
ix2021 REPORTING
We will report on our research findings during the year. In a virtual meeting in June we will
give a Mid-Year Progress Report to inform the Industrial Associates of the status of the
projects and the results in hand.
The detailed results of the individual projects will be presented at the Annual Review
Meeting in Miami. We anticipate an improvement in the Covid-19 situation by the fall and
hope that we will be able to meet in person. However, we are still planning to offer a hybrid
model, whereby the presentations will be also transmitted simultaneously online. The dates
for these two meetings are:
JUNE 9, 2021 – MID-YEAR PROGRESS REPORT
Executive style presentation of the projects and results in hand followed by a discussion.
The meeting will be online starting at 9 o’clock in the morning (USA-EST) and 3 pm
(UTC+01:00) in continental Europe. The meeting is expected to last about 2 – 3 hours. We
will send out a program and other details by early May.
OCTOBER 18 - 19, 2021 - ANNUAL REVIEW MEETING
The results of the projects detailed in this prospectus will be presented at the Annual
Review Meeting in Miami, October 18 - 19, 2021. We will send out information on the
logistics for the meeting in the second quarter of 2021.
2021 FIELD SEMINARS
The pandemic prevented the field trip in 2020 that is usually held in conjunction with the
Annual Review Meeting. Because there is still uncertainty regarding future travel, details of
the meeting field trip, together with other field trips normally offered during the year, are not
included here. We will announce these field trips as soon as the situation allows.
COSTS
The contribution of each Industrial Associate towards the research budget is $55,000. This
contribution complements funding the CSL-CCR receives from national funding agencies such
as the National Science Foundation (NSF), the International Ocean Discovery Program (IODP)
and other funding agencies. Contributions from our Industrial Associates are mainly used to
support students working within the CSL, while funding for the data acquisition, such as
seismic and coring expeditions and the funds for new equipment have been made possible by
grants from federal funding agencies.
xiDepartment of Marine Geosciences
University of Miami
CERTIFICATE PROGRAM
APPLIED CARBONATE GEOLOGY
PURPOSE AND GOALS OF THE CERTIFICATE PROGRAM
The goal of the Certificate Program is to provide first-rate continuing education to
professionals or geology students who want to become experts in carbonate geology. To reach
this goal courses are offered in carbonate sedimentology, seismic stratigraphy, petrophysics,
and geochemistry for an advanced knowledge and understanding of carbonate systems.
OVERVIEW AND COSTS
A Certificate in Applied Carbonate Geology requires the successful completion of 16 course
credits assembled from 11 courses in the program (see back). The courses combine classroom
teaching, laboratory classes and applied projects. No thesis will be written.
Courses for the Certificate Program will be offered in the Spring Semester and the 1st Summer
Session of 2021. The student/geoscientist will be in residence for 6 months. The current
tuition fee is $2,000/credit.
REQUIREMENTS FOR ADMISSION AND REGISTRATION
A bachelor degree or equivalent degree is required but can be offset by years of working
experience. No GRE or TOEFL are required. Registration for the Certificate Program started in
the summer of 2016 and is handled by the Graduate Studies Office of RSMAS.
Registration for the Certificate Program opens each year in June for classes in the following
year. Registration is online using the UM-RSMAS graduate program website.
LEARNING OUTCOMES OF
THE CERTIFICATE PROGRAM
Learning Outcome 1:
Geoscientists/students will gain a broad knowledge of
carbonate geology and geophysics.
Learning Outcome 2:
Geoscientists/students will learn to incorporate the
acquired knowledge and available data and tools into the
workflow of applied projects.
Learning Outcome 3:
Geoscientists/students will learn oral and written
communication skills and will be able to communicate
their ideas and findings to peers, managers, and
administrators.
xiiiINSTRUCTORS IN THE PROGRAM
Gregor P. Eberli Seismic Sequence Stratigraphy Professor
Peter K. Swart Carbonate Geochemistry Professor
James S. Klaus Paleoecology, Geomicrobiology Assoc. Professor
Donald F. McNeill Sedimentology, Stratigraphy Scientist
Mara R. Diaz Molecular and Geomicrobiology Scientist
Ralf J. Weger Petrophysics Scientist
John Dolson Carbonate Petroleum Geology Lecturer
Greta Mackenzie Petrography Assoc. Scientist
Paul M. (Mitch) Harris Carbonate Geology Visiting Scientist
OFFERED COURSES
MGS 611 3 Cr Earth Surface Systems
MGS 641 2 Cr Field Evaluation of Fossil Platforms,
Margins, and Basins
MGS 601 1 Cr Seminar in MGS
MGS 678 2 Cr Field Seminar: Facies Successions on
Great Bahama Bank
MGS 688 2 Cr Field Seminar: Heterogeneity of a
Windward Margin
MGS 784 2 Cr Seismic Interpretation of Carbonate
Systems
MGS 785 2 Cr Petrophysics of Carbonates
MGS 786 2 Cr Microbial Carbonates
MGS 787 2 Cr Carbonate Diagenesis and Petrography
MGS 788 2 Cr Analysis in Carbonate Cores
MGS 789 2 Cr Petroleum Geology in Carbonates
For additional information about the
CSL - Center for Carbonate Research
or the
Certificate Program
Applied Carbonate Geology
please contact:
Gregor P. Eberli
Director of the
CSL-Center for Carbonate Research
Rosenstiel School of
Marine and Atmospheric Science
University of Miami
4600 Rickenbacker Causeway
Miami, FL 33149
+1 (305) 421- 4678
geberli@rsmas.miami.edu
xivPROPOSED RESEARCH
2021MARINE CARBONATE SEDIMENTATION IN AN ACTIVE RIFT
BASIN (RED SEA – GULF OF AQABA)
Sam Purkis and Paul (Mitch) Harris
PROJECT OBJECTIVES
Develop a rich geophysical dataset for the northern Red Sea capturing the
diversity in styles of syn-rift carbonate deposits.
Examine this dataset to disentangle the varied controls of carbonate deposition
through time in an active rift basin.
PROJECT RATIONALE
Enabled by the 2020 ‘Deep Blue’ research cruise, a comprehensive multibeam
dataset is being acquired in late 2020 offshore the Saudi Arabian coastline straddling
the coastal shelf to the full depth of the Red Sea spreading axis (Fig. 1). The
multibeam bathymetry will be supplemented with sub-bottom lines, ADCP
measurement of current systems, and ground-truthed by ROV and submersible dives.
The Red Sea is an active maritime rift system which is unique in the world. Interest
in rifts is considerable because they are vital in terms of understanding plate
movements and their related seismicity, and because the deep, narrow basins that
they yield provide motifs of carbonate deposition that are distinct from more common
shelf and open-marine settings (Purkis et al., 2012). Spanning both photic and
Figure 1: The location of the planned survey of the Northern Red Sea and Gulf of Aqaba.
15hemipelagic environments, the deposition of carbonates in the Red Sea is broadly directed by the varied bathymetry delivered by the overall tectonic grain of the rift, and, more locally by pervasive salt tectonics. To the latter, the salt formations likely owe their origin to hydrothermal activity associated with shallow-igneous intrusions along the spreading axis of the basin. Typically associated with fault boundaries, halokinesis in the deep marine presents ductile, glacier-like salt flows which mantle the seabed, much like more conventional gravity flows, plus salt injectites (extrudites) which pierce the seafloor, add to its topography, and disrupt the Pliocene-Quaternary overburden (Mart and Ross, 1987; Mitchell et al., 2010; Augustin et al., 2014). These processes serve to direct the evolution of bathymetry and the subsequent deposition and accumulation of post-salt pelagic and hemipelagic carbonates. The diversity of motifs of carbonate deposition is even more stark in the photic zone. Here, reefal carbonates veneer fault-bounded structural elements of the rift, but also develop atop the pinnacles of salt diapirs. Carbonates deposited on the latter are often abruptly disrupted by collapses of the seafloor created by partial-local removal of mass by salt dissolution and/or suberosion (e.g. Ehrhardt and Hübscher, 2015). Paleo-wind and abundant siliciclastics supplied from the mountains which demark the rift shoulders add further depositional complexity to the syn-rift carbonates. In aggregate, these varied controls acting in the Red Sea deliver arguably the greatest diversity of shore-attached and isolated carbonate platforms witnessed anywhere on the modern Earth. As such, the North Red Sea is an ideal venue to examine syn-rift carbonates and their depositional controls. APPROACH A new geophysical dataset will be acquired, ground-truthed, and interrogated to examine the syn-rift carbonates of the northern Red Sea. Emphasis will be placed on disentangling the controls on plan-view morphology and internal stratal patterns of the deposits, with a view to developing a modern analog to Tertiary rift basins in the South China Sea and Mesozoic basins of the South Atlantic. SIGNIFICANCE Syn-rift carbonate platform strata can form important petroleum reservoirs within syn-rift basins. They also provide critical records for understanding the tectonic evolution and depositional history of rift systems. This unique dataset from the Red Sea has the potential to provide enhanced understanding in such settings. REFERENCES Augustin, N., Devey, C.W., van der Zwan, F.M., Feldens, P., Tominaga, M., Bantan, R.A. and Kwasnitschka, T., 2014. The rifting to spreading transition in the Red Sea. Earth and Planetary Science Letters, 395, pp.217-230. Ehrhardt, A. and Hübscher, C., 2015. The northern Red Sea in transition from rifting to drifting-lessons learned from ocean deeps. In: The Red Sea (pp. 99-121). Springer, Berlin, Heidelberg. Mart, Y. and Ross, D.A., 1987. Rifts and diapirs in the northern Red Sea. Mar. Geol, 74, pp.173-190. Mitchell, N.C., Ligi, M., Ferrante, V., Bonatti, E. and Rutter, E., 2010. Submarine salt flows in the central Red Sea. GSA Bulletin, 122(5-6), pp.701-713. Purkis, S.J., Harris, P.M. and Ellis, J., 2012. Patterns of sedimentation in the contemporary Red Sea as an analog for ancient carbonates in rift settings. Journal of Sedimentary Research, 82(11), pp.859- 870. 16
CARBONATE CONTOURITE DRIFT SYSTEMS
Gregor P. Eberli, Sara Bashah and Ralf J. Weger
PROJECT OBJECTIVES
Continue assembling dimensions and sedimentary characteristics of carbonate
contourite systems for a comprehensive data base of such systems.
Examine the depositional processes of coarse and fine-grained current deposits
in carbonates.
Evaluate the potential of carbonate contourite systems as reservoir and seals.
PROJECT RATIONALE AND GOALS
The increased exploration in deep water has, over the years, triggered research in
marine depositional processes other than mass gravity flows. As a result, the
importance of bottom currents in deep sea sedimentation is now recognized both on
a bed scale (contourite) and on the large sedimentary bodies (contourite drifts)
(Rebesco et al., 2014). In addition, case studies document the interaction of bottom
currents with mass gravity flows. This interaction has the potential to increase
reservoir quality in the siliciclastic deep-water reservoirs as is the case in the giant
reservoirs (Coral and Mamba fields) offshore Mozambique. Because bottom currents
preferentially move fine-grained sediments, they produce thickness and
petrophysical variability in unconventional reservoirs.
The most prolific production from current-controlled strata is in the Upper
Cretaceous and Danian chalk fields in the Central Graben of Denmark, where both
structural and non-structural trapping mechanisms exist (Megson,1992). In other
plays, like coarse-grained distally steepening ramp settings, the current contribution
might not have been recognized, fanning the notion that current-controlled deposits
are not good reservoirs. It is our working hypothesis that portions of the carbonate
contourite drift systems have reservoir potential, although they are generally
considered a risky play. A thorough knowledge of these systems is needed to reduce
this risk.
Figure 1: Miocene platforms on the Marion Plateau surrounded by carbonate contourite
drifts, illustrating the importance of drift deposition in off-bank areas in the Neogene (from
Bashah et al., 2020).
17PROJECT PROGRESS AND FUTURE PLANS For a comprehensive overview of the processes that form carbonate contourite systems, we plan to examine carbonate drifts in various tectonic and depositional settings. In past years, we have described three carbonate-specific types of contourite drifts that develop because of a feedback between steep morphology and sediment production and delivery to the currents (Eberli and Betzler, 2019), and have started to examine the influence of currents on the flank architecture of isolated platforms (Betzler and Eberli, 2019). These studies form the starting point of an evolving data base of carbonate contourite drift systems that includes their dimensions and composition and relates these parameters to the oceanographic setting. In order to understand the distribution of coarse-grained (potential reservoirs) and fine-grained deposits (seals) within the carbonate drift system, a thorough examination of the depositional processes is needed. These processes will be studied in both the modern and ancient current-controlled settings. A special emphasis will be laid on the conditions that produce supercritical flow and prolonged phases of bedload transport that are likely to produce well-sorted coarse deposits. Carbonate contourite drift deposits have characteristic log signatures that differ from shallow-water and slope carbonate successions (Giddens et al., 2020). We plan to document and explain these petrophysical properties with laboratory experiments. These results and log data from carbonate drifts will be assembled in a data base. SIGNIFICANCE Depositional processes in the off-bank and deep-water areas are the combined product of pelagic fallout, mass gravity flows, and bottom currents. This research will improve the knowledge of the current component on deep water deposition and improve depositional models of slope and ramp carbonates that until recently mostly considered gravity flows to be the main process. REFERENCES Bashah S. and Eberli, G.P. (2020) Timing and composition of contourite drifts on the Marion Plateau, NE Australia - implications for carbonate platform architecture. CSL- Annual Review Meeting Abstract Book, p. 95 – 99. Betzler C. and Eberli G.P. (2019) The Miocene start of modern carbonate platforms. Geology, v. 47, p. 771-775 Eberli, G.P. and Betzler, C. (2019) Characteristics of modern carbonate contourite drifts. Sedimentology, v. 66, p. 1163-1191. Giddens E., Eberli, G.P., Weger, R. and Mackenzie G. (2020) Petrophysical Properties of Carbonate Contourites. CSL- Annual Review Meeting Abstract Book, p. 99 – 101. Megson, J.D. (1992) The North Sea Chalk Play: examples from the Danish Central Graben. Geological Society, London, Special Publications, 67, 247-282. Rebesco, M., Hernández-Molina, F.J., Van Rooij, D. and Wahlin, A. (2014) Contourites and associated sediments controlled by deep-water circulation processes: state-of-the art and future considerations. Mar. Geol. v. 352, p. 111–154. 18
THE RELATIONSHIP BETWEEN CARBONATE SLOPES AND
CONTOUR CURRENTS
Sara Bashah and Gregor P. Eberli
WORKING HYPOTHESES
Current strength along carbonate ramps, shelves and isolated platforms
determines the
- dip of the platform flanks
- dip of the mounded contourite drift
- grain size of the contourite drift
Carbonate slopes steepen worldwide in the late Middle Miocene after the onset
of modern ocean currents at approximately 13 Ma.
PROJECT RATIONALE
It has been proposed
that carbonate slope
architecture is
controlled by the
amount of deposition,
by-pass or erosion of
mass gravity flows
(Schlager and Camber,
1986) and by the fabric
of the slope material
(Kenter, 1990). The
flanks of carbonate
platforms around the
world after 13–10 Ma
have, however, not
only been constructed
by mass gravity
deposits, but equally
by contourites with
distinct drift and moat
geometries. This style
of flank architecture is
typical of tropical
carbonate platforms
growing in the
Neogene icehouse
world. Ocean currents
reduce sedimentation
by particle sorting or Figure 1: Selected seismic lines from A: Great Bahama Bank,
winnowing and even by Atlantic. B: Marion Plateau, northeast Australia. C: Maldives,
eroding slopes (Betzler Indian Ocean.
and Eberli, 2019). In
19this project we will document the evolution of carbonate slopes in the Bahamas, on the Marion Plateau, and in the Maldives, and their relationship with the along slope sediment transport by contour currents. These platforms show an abrupt onset of current activity along their slopes (Red lines in Fig. 1). DATA SETS For this study, four data sets consisting of seismic, cores, and log data, from ODP Leg 194, ODP Leg 133, ODP Leg 166, and IODP Expedition 359 are analyzed. Age models are based on biostratigraphy and Sr-isotope dating from these ODP and IODP sites. APPROACH AND WORKFLOW To achieve the goals regarding the influence of contour currents on the carbonate platform slopes, we use the following workflow: SIGNIFICANCE The outcome of this study will improve our understanding of the influence of currents on carbonate platform architecture. The results will prompt a revision of facies models of carbonate platform slopes that have been based mostly on the assumption that they have been constructed by mass gravity flow deposits. This knowledge potentially helps discriminate current-influenced platforms from those evolving during times with less ocean circulation. REFERENCES Betzler C. and Eberli, G.P., 2019, Miocene start of modern carbonate platforms. Geology, v. 47, p. 771– 775 Schlager, W. and Camber, O., 1986, Submarine slope angles, drowning unconformities and self-erosion of limestone escarpments: Geology, v. 14, p. 762–765. Kenter, J. A. M., 1990. Carbonate platform flanks; slope angle and sediment fabric. Sedimentology v. 37, p. 777-794. 20
TOWARDS A DEPOSITIONAL MODEL OF COARSE-GRAINED
DELTA DRIFT DEPOSITS, MAIELLA, ITALY - YEAR 2
Gregor P. Eberli, Mark Grasmueck, and Ralf J. Weger
PROJECT OBJECTIVES
Test the hypothesis that stratal succession of the delta drift in the Maiella is
the combined product of hyperpycnal flow of a sediment-laden semi-
continuous current flowing through the feeder channel and supercritical flow
in the adjacent basin.
Document the proximal to distal facies trends within the delta drift of the
Maiella and assess the flow conditions necessary for producing the observed
facies distribution.
PREFACE
This project was planned for last year with an approach that combined outcrop work
and visualization of the clast distribution in a 3D GPR data set acquired in the quarry
of Madonna della Mazza. This visualization portion of the project was completed
(Grasmueck et al., 2020) but travel restrictions prevented us from doing the
fieldwork, which we plan to complete this year.
PROJECT RATIONALE
The Upper Cretaceous Orfento Formation in the Maiella Mountains (Italy) is a largely
mud-free coarse-grained succession of redeposited carbonates with sedimentary
structures that are indicative for deposition of subaqueous high-density sediment
flows. Yet, the succession does not fit in any of the existing turbidite fan models and
recently these deposits have been recognized as a delta drift (Eberli et al., 2019).
This carbonate delta drift succession in the Maiella displays characteristics of highly-
concentrated turbidity current deposits (Fig. 1). Other elements, like scours filled
with pebble- and gravel-sized clasts, and erosive surfaces are typical expressions of
transitions from supercritical to subcritical flow (Postma and Cartigny, 2014). Other
beds display structures that are associated with hyperpycnal flow. Hyperpycnal flow
is commonly associated with sediment laden river water. Yet, isolated carbonate
Figure 1:
Schematic
display of
the Maiella
drift delta
as plan view
and dip and
strike cross-
sections
(from Eberli
et al.,
2019).
21platforms do not have fluvial transport and thus, the hyperpycnal flow is likely
generated by the ocean current flowing through a feeder channel where it entraps
sediment. The large-scale geometry of coarse downlapping lobes in the Maiella delta
drift are reminiscent of homopycnal jet outflow typical in Gilbert-type deltas. Thus, it
is likely that, depending on the sediment load, both flow mechanisms occur in the
delta drift.
PROJECT OBJECTIVES
This project aims to test the hypothesis that a sediment laden ocean current can
yield flow conditions to a long-lived homopycnal and hyperpycnal flow, producing the
observed bedload transport by the shear provided by the overpassing hyperpycnal
sediment laden ocean current (Fig. 2). In addition, hydraulic jumps caused by the
topography are thought to produce transitions from subcritical to supercritical flow
and several of the observed sedimentary features.
Figure 2: Clast
distribution in the
Madonna dell
Mazza quarry.
Clasts appear as
white specks in
the quarry floor
and walls; larger
clasts are
outlined in
yellow. Inset is
schematic display
of the clasts
deposited by
hyperpycnal flow
(Zavala et al.,
2011).
SIGNIFICANCE
This study will provide an assessment of the sedimentologic processes of jet flow
generated by ocean currents in feeder channels and their depositional products. The
results will identify criteria to distinguish coarse-grained contourite drifts from
carbonate turbidite successions.
REFERENCES
Eberli, G.P., Bernoulli, D., Vecsei, A., Sekti, R., Grasmueck, M., Lüdmann, T., Anselmetti, F.S., Mutti,
M. and Della Porta, G. (2019) Cretaceous Carbonate Drift Delta in the Montagna della Maiella, Italy.
Sedimentology, v. 66, p. 1266-1301. doi: 10.1111/sed.12590.
Grasmueck, M., Eberli, G.P., Mackenzie, G. and Weger R.J. (2020) Visualizing structures in coarse-
grained delta drift deposits, Maiella, Italy. CSL – Annual Review Meeting Abstract Book, p. 101 -103.
Postma, G. and Cartigny, M.J. (2014) Supercritical and subcritical turbidity currents and their deposits—
A synthesis. Geology, v. 42, p. 987-990.
Zavala, C., M. Arcuri, M. Di Meglio, H. Gamero Diaz and C. Contreras, 2011, A genetic facies tract for
the analysis of sustained hyperpycnal flow deposits. AAPG Studies in Geology v. 61, p. 31–51.
22PETROPHYSICS OF CARBONATE DRIFTS
Ralf J. Weger, Gregor P. Eberli and Greta Mackenzie
PROJECT OBJECTIVES
Prepare a data report of the samples from the delta drift in the Maldives.
Complete the analysis of the petrophysical properties of delta drift deposits in
the Maiella.
Relate log signature of carbonate drift deposits and relate to drift type and
mineralogy.
Produce a catalogue for discriminating logs of slope and basin deposits from
carbonate contourite drifts.
BACKGROUND AND PROJECT RATIONALE
For her Ph.D. research, Emma Giddens started to assemble a large data set of
laboratory measurements of petrophysical properties of the Miocene delta drifts in
the Maldives and Cretaceous drift strata in the Maiella. Photomicrographs of the
samples provide information on the grain size and sorting, as well as pore types of
these carbonate drift samples. Because of the good sorting in these current-controlled
deposits, the correlation between porosity and permeability as well as porosity and
velocity are better than in shallow-water carbonates. Likewise, the formation factor
m has a narrow range from 1.7 -2.9 (Giddens et al., 2019). The question is, is this
unique petrophysical behavior also present in finer-grained carbonate contourite
drifts? A preliminary comparison of log data from the coarse-grained delta drift in the
Maldives and the confined drift in the Santaren Channel in the Bahamas, reveal
Figure 1: Comparison of logs through the fine-grained Santaren Drift in the Bahamas
and the coarser-grained drift in the Maldives. Both log suites show similar log
characteristics and a uniform behavior with little variations.
23similar log characteristics (Fig. 1). Both logs display little variation in several logs, indicating a generally uniform log signature of carbonate contourite drifts. This project is intended to complete Emma’s research with the goal of assembling a comprehensive petrophysical database of carbonate contourite drifts. These data from both laboratory and log will be compared to existing data from prograding slope carbonates to provide guidance for distinguishing petrophysical properties between carbonate contourite drifts and carbonate slope and turbidite packages. WORKPLAN Laboratory analyses: Additional samples from the Maiella delta drift will add to the existing data set. In addition, velocity, porosity, resistivity and permeability will be measured on plug samples from drifts on the Marion Plateau in Australia and from the Bahamas. Some of the Marion Plateau samples have been measured in earlier studies by Guido Bracco Gartner (unpublished) and we will request samples from ODP Site 1006 from the Santaren Drift in the Bahamas. The Marion drifts are slightly different in mineralogy as they contain admixtures of siliciclastics and less aragonite than the Maldives and Bahamas drifts. Petrographic Analysis: From each plug measured, a thin section has been cut for petrographic analysis allowing grain size and sorting to be determined, as well as pore structure to be assessed and associated with the petrophysical measurements. Texture and mineralogy of each sample will be determined, and the pore type of each sample will be analyzed with digital image analysis. SEM imagery will be used to assess the micropore structure. Log analysis: The log data through the studied drifts were collected by Schlumberger during the ODP and IODP expeditions. These log suites from cores drilled into the three contourite drifts will be used to document the log characteristics of the different drift deposits. Comparison to slope successions: In all three study sites, contourite drifts are deposited on top of slope carbonates, allowing the petrophysical properties of these two systems to be compared. Kenter et al. (2002) measured the slope sections in the Bahamas and Ehrenberg et al. (2004) assembled the data for the Marion Plateau, while Emma Giddens measured the slope carbonates in the Maldives. GOAL The goal of this study is to assemble a comprehensive petrophysical database of carbonate contourite drifts. These deposits are potentially either underexplored carbonate reservoirs or seals in the petroleum system. REFERENCES Giddens, E.L., Eberli, G.P., and Weger, R.J. (2019) Comparing velocity and resistivity data from Miocene drift deposits in the Maldives to Cretaceous drift deposits in the Maiella, Italy. CSL – Annual Review Meeting Abstract Book,, p. 103 – 106. Kenter, J.A.M., Anselmetti, F.S., Kramer, P.A., Westphal, H. and Vandamme, M.G.M. (2002) Acoustic properties of “young” carbonate rocks, ODP Leg 166 and Boreholes Clino and Unda, Western Great Bahama Bank: Journal of Sedimentary Research, v. 72, p. 129-137. Ehrenberg, S. N., Eberli, G.P. and Bracco Gartner, G.L. (2004) Data report: Porosity and permeability of Miocene carbonate platforms on the Marion Plateau, ODP Leg 194: Proc. ODP, Sci. Results 194, p. 1–217. 24
SEISMIC FACIES AND STRATIGRAPHY OF THE YUCATAN
PLATFORM
Elizabeth Guzman and Gregor P. Eberli
PROJECT OBJECTIVES
Assess the tectonic deformation of the Cretaceous portion of the Yucatan
Platform and place the evolution of the Yucatan Platform into the regional
context of Caribbean tectonics.
Map the seismic sequences in the intraplatform seaway of the Yucatan
Platform.
Document the influence of the currents on the Neogene deposits on the eastern
portion of the Yucatan platform.
REGIONAL SETTING AND PROJECT RATIONALE
The Yucatan Peninsula and adjacent shelf form the 350,000 km2 Yucatan Platform.
The platform hosts the Chicxulub impact crater generated by the asteroid that led to
the mass extinction at the end of the Cretaceous (Schulte et al., 2010). The asteroid
impact deformed the underlying basement and created a multi-ring crater that is 200
km in diameter. Scientific drilling penetrated the post-impact carbonates, an ~ 130
m thick sequence of impact strata and shocked and fractured basement rocks (Gulick
et al., 2016). Regional seismic data reveals that the impact crater is located within a
large N-S trending depression – the Intra-platform Yucatan Basin (Fig. 1; Guzman et
al., 2019).
The Cretaceous strata displays faults and deformation that are reminiscent of
wrench faults. The question is how much of this deformation is the result of the
asteroid impact and how much is related to changes in the regional stress regime?
The boundary between the Cretaceous and Paleocene strata is a well-defined seismic
horizon. The Yucatan Basin that houses the impact crater is filled with prograding
clinoforms, probably starting as early as the Early Eocene (Whalen et al., 2013,
Canales-García et al., 2018).
Figure 1:
Topography of the
Yucatan Platform at
the Cretaceous-
Paleogene
boundary,
displaying the
roughly north-
south oriented
Intra-platform
Yucatan Basin,
which is nearly 180
km wide and up to
1200 m deep (from
Guzman et al.,
2019).
25This project aims to a) assess the structural evolution of the Yucatan Platform, b) analyze the prograding sequences with regards to sea-level control, and c) evaluate how many of the prograding clinoforms at the eastern fringes of the Yucatan Platform are influenced by the Yucatan Current that today flows across this area. A comparison of the timing and style of the deformation and the infill of the intraplatform basin are strikingly similar to the deformations observed in Great Bahama Bank and the Straits of Andros that are also filled with prograding clinoforms. We plan to compare and contrast these two areas. DATA SET AND WORKPLAN The seismic data in hand consists of seismic lines collected in conjunction with the IODP drilling of the impact crater, older data collected by the University of Texas, and newer data from the National Hydrocarbons Information Center (CNIH) in Mexico. In addition, we expect to secure more seismic data from CNIH in Mexico to cover crucial areas for our study goals. We plan to build a robust seismic stratigraphic framework of the Yucatan Platform that relies on the ages acquired by dating material provided by existing onshore and offshore cores. Faults and deformation will be mapped within this framework and placed into the larger regional context. A detailed sequence stratigraphic analysis will be performed in the prograding sequences that fill the intraplatform basin. Results of the sequence analysis will be compared to timing and style of the prograding clinoforms in the Straits of Andros within Great Bahama Bank. SIGNIFICANCE The Yucatan Platform is a large and important – yet underexplored - carbonate platform within the Caribbean. It also offers the opportunity to investigate the consequences of a large impact on the deformation and subsequent recovery of a carbonate platform. REFERENCES Canales-García, I., Urrutia-Fucugauchi, J., and Aguayo-Camargo, E. (2018) Seismic imaging and attribute analysis of Chicxulub Crater central sector, Yucatán Platform, Gulf of Mexico. Geologica Acta, v.16, p., 215-235 Gulick, S., Morgan, J., and Mellett, C.L. (2016) Expedition 364 Scientific Prospectus: Chicxulub: drilling the K-Pg impact crater. International Ocean Discovery Program. http://dx.doi.org/10.14379/iodp.sp.364.2016 Guzman E., Aguayo, E. and Eberli G.P. (2019) Evidence of a Large Intra-platform Basin on the Yucatan Peninsula in the Vicinity of the Chicxulub Crater. CSL -Annual Review Meeting Abstract Book, p. 107- 110. Schulte, P., Alegret, L., Arenillas, I., Arz, J.A., Barton, P.J., Bown, P.R., Bralower, T.J., Christeson, G.L., Claeys, P., Cockell, C.S. and Collins, G.S., 2010. The Chicxulub asteroid impact and mass extinction at the Cretaceous-Paleogene boundary. Science, 327(5970), pp.1214-1218. Whalen, M.T., Gulick, S.P.S., Pearson, Z.F., Norris, R.D., Perez Cruz, L. and Urrutia Fucugauchi, J. (2013). Annealing the Chicxulub impact: Paleogene Yucatán carbonate slope development in the Chicxulub impact basin, Mexico. In Verwer, K., Playton, T.E., and Harris, P.M. (Eds.), Deposits, Architecture, and Controls of Carbonate Margin, Slope and Basinal Settings. Special Publication— SEPM (Society for Sedimentary Geology), v. 105, p. 282–304. 26
EVOLUTION OF A MODERN OOID SAND ISLAND - SOUTH
JOULTER CAY, GREAT BAHAMA BANK
Juan Carlos Laya1, Paul (Mitch) Harris, and Miles Frazer2
1)
Texas A&M University
2)
Chevron Energy Technology Company
PROJECT OBJECTIVES
To complete acquisition of high-resolution drone imagery and a DTM for better
delineation of the morphology of Holocene ooid sand ridges forming South
Joulter Cay (SJC) allowing a detailed interpretation of the processes that
formed the island.
To further calibrate the timing of key depositional events within the island’s
history by select radiometric dating.
PROJECT RATIONALE
The Joulters ooid sand body covers some 400km2 of Great Bahama Bank north of
Andros Island. It is famous as a site for the study of high-energy carbonate sediments
and is a central analog for understanding oolitic grainstone reservoirs due to the
clearly observable interplay between vast stabilized sand flats and active ooid bars
(Harris, 2019). The geological story of the three Joulter Cays (low lying islands),
however, deserves equal attention. The Joulter Cays, built of lightly cemented oolitic
and peloidal sediments, form along the eastern, windward-facing margin of the ooid
sand body. Previous field mapping and local coring placed island development within
the story of sand body development and established they are a very recent feature
with radiocarbon dating showing
ages from ~2000 ybp to present
(Harris, 1979). These islands,
while small in areal extent, act to
extensively modify the distribution
of energy across the top of the
Joulters sand body, blocking wave
energy from the open ocean to the
east, and confining tidal flow to the
channels that lie to the south, the
north, and between each island
(Fig. 1). This aspect of an energy
barrier introduces a sudden shift
towards muddy facies in the
immediate lee of the islands and
isolates ooid production to tidal
channels and their associated ebb
and flood lobes. Figure 1. Facies map for SJC and surroundings. The
island is bounded at the south by the largest and
APPROACH deepest tidal channel observed within the Joulters
sand body and fronted by an active ooid sand shoal.
Our ongoing examination of SJC, Variably vegetated muddy sandflats develop on the
the largest of the islands, targets lower energy, lee side of the island. Map generated
a better delineation of the timing by Purkis Partnerships Ltd for Chevron ETC.
27and processes that formed the island. High resolution imagery and a DTM constructed
from a drone survey improve on previous maps. Historically, SJC records a period of
higher ooid accumulation rate than occurs locally in the sand body today; ooid sand
production was greater than the system’s ability to hydrodynamically redistribute
these sediments. Ridge topography on the island suggests that active sand bars
locally built to beaches and back-beach dune ridges formed repeatedly. A scenario
for island development based on existing data (Fig. 2) emphasizes growth stages
reflecting variations in dispersal of ooid sands by tidal channels, wind and wave
energy, and longshore and storm-related currents. Topographic profiles extracted
from the DTM show that higher than average beach ridges are associated with the
initiation of each of the island’s growth stages, suggesting that the island’s
morphological evolution is closely integrated into the wider evolution of sediment
generation and transport within the overall sand body.
Figure 2. DEM
of South
Joulter Cay
showing and
describing
growth stages
based on
ridge
morphology.
SIGNIFICANCE
This study focuses specifically on the process by which a key facies transition occurs,
namely the nucleation and growth of islands within accommodation-restricted sand
bodies. It has particular impact on facies interpretation and correlation within
subsurface grainstone reservoirs as well as the interpretation of their sequence
stratigraphic and diagenetic development. The islands, and SJC in particular,
introduce a new suite of Holocene facies (beach, back-beach storm ridges, tidal flats)
into the dominantly subtidal record of the overall sand body. Their presence also
armors the sand body at its most energetic margin and the topography of the islands
significantly influences the local water movement and thus depositional patterns. As
such, the most recent geologic record shows a facies transition that, if seen out of
context, may be misinterpreted as being caused by a sudden increase in water depth,
when the truth is exactly the opposite. The development of islands like Joulters also
introduces an element of spatially constrained meteoric diagenesis (cementation and
dissolution) contemporaneous to sand generation and deposition (Halley and Harris,
1979).
REFERENCES
Halley, R. B. and Harris, P. M., 1979, Fresh-Water Cementation of a 1000-Year-Old Oolite: Jour. Sed.
Petrology, v. 49, p. 969-987.
Harris, P. M., 1979, Facies Anatomy and Diagenesis of a Bahamian Ooid Shoal: Sedimenta 7,
Comparative Sedimentology Laboratory, Univ. Miami, Miami Beach, FL, 163 p. (posted in 2009 on
AAPG Search and Discovery as Article #60022)
Harris, P.M., 2019, Lessons from a Modern Carbonate Sand Body – A Personal Experience of
Comparative Sedimentology: The Depositional Record 2019; 5:438-450.
https://doi.org/10.1002/dep2.58
28SEDIMENT TRANSPORT ON THE GREAT BAHAMA BANK -
INSIGHTS FROM FAIR- & STORM-WEATHER CONDITIONS
Cecilia Lopez-Gamundi, Brian Barnes1, Thomas Dobbelaere2, Emmanuel Hanert2,
Paul (Mitch) Harris, and Sam Purkis
1)
University of South Florida, United States
2)
Université Catholique De Louvain, Belgium
PROJECT OBJECTIVES
To assess the sediment budget of Great Bahama Bank (GBB) via quantification
of sediment production, transport, and on- and off-platform accumulation.
To evaluate the balance between fair and storm-weather conditions on
sediment transport.
To quantify volumetric sediment loss from the platform top via analysis of off-
margin geophysical data.
PROJECT RATIONALE
Recent GBB studies have primarily focused on either platform sediment production,
mapping of on- and off-platform sediment distributions, or analyzing the variable
filling of accommodation space. The platform’s sediment budget has received little
attention, which is the motivation for this project. SLIM hydrodynamic modelling
(developed at UCL, Belgium) indicates that fair-weather conditions do not deliver
sufficiently vigorous current velocities to resuspend meaningful volumes of sediment.
By contrast, storm conditions do. Analysis of satellite-derived turbidity data suggest
a seasonal cycle to sediment lofting, upon which storms overprint (Fig. 1).
Figure 1. Timeseries of 645 and 667 nm MODIS reflectance on a portion of GBB (location
map, top right). Elevated 667 nm reflectance (blue line) suggest seasonal variability in
suspended sediment attributed to the passage of winter cold fronts (winter = gray bars
beneath x-axis). Elevated 645 nm reflectance values (black line) capture storm-induced
lofting of seabed sediment. Major hurricanes and respective categories labeled with colored
arrows. Data courtesy of Brian Barnes (USF).
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