Searching for seafloor massive sulfides: a quantitative review of high-resolution methods in deep sea sonar bathymetry for mining applications

2014 ◽  
Vol 35 (2) ◽  
pp. 157-174
Author(s):  
Michael Mitchley ◽  
Michael Sears
Keyword(s):  
High Resolution ◽  
Deep Sea ◽  
Quantitative Review ◽  
Massive Sulfides

Deep-sea panoramas: Progress and remaining challenges in late Miocene stratigraphy and climate

2021 ◽  
Author(s):  
Anna Joy Drury ◽  
Thomas Westerhold ◽  
David A. Hodell ◽  
Mitchell Lyle ◽  
Cédric M. John ◽  
...  
Keyword(s):  
High Resolution ◽  
Ocean Circulation ◽  
Late Miocene ◽  
Deep Sea ◽  
Deep Ocean ◽  
High Resolution Data ◽  
Ongoing Work ◽  
Climate Evolution ◽  
Deep Ocean Circulation ◽  
Geological Timescale

<p>During the late Miocene, meridional sea surface temperature gradients, deep ocean circulation patterns, and continental configurations evolved to a state similar to modern day. Deep-sea benthic foraminiferal stable oxygen (δ<sup>18</sup>O) and carbon (δ<sup>13</sup>C) isotope stratigraphy remains a fundamental tool for providing accurate chronologies and global correlations, both of which can be used to assess late Miocene climate dynamics. Until recently, late Miocene benthic δ<sup>18</sup>O and δ<sup>13</sup>C stratigraphies remained poorly constrained, due to relatively poor global high-resolution data coverage.</p><p>Here, I present ongoing work that uses high-resolution deep-sea foraminiferal stable isotope records to improve late Miocene (chrono)stratigraphy. Although challenges remain, the coverage of late Miocene benthic δ<sup>18</sup>O and δ<sup>13</sup>C stratigraphies has drastically improved in recent years, with high-resolution records now available across the Atlantic and Pacific Oceans. The recovery of these deep-sea records, including the first astronomically tuned, deep-sea integrated magneto-chemostratigraphy, has also helped to improve the late Miocene geological timescale. Finally, I will briefly touch upon how our understanding of late Miocene climate evolution has improved, based on the high-resolution deep-sea archives that are now available.</p>

scholarly journals Graphic correlation of deep sea and shallow marine deposits from the Central American Isthmus region: implications for Late Neogene paleoclimatology

1992 ◽  
Vol 6 ◽  
pp. 88-88
Author(s):  
Harry J. Dowsett
Keyword(s):  
Costa Rica ◽  
High Resolution ◽  
Ocean Circulation ◽  
Deep Sea ◽  
Sea Surface ◽  
Central American ◽  
Major Barrier ◽  
Late Neogene ◽  
The Caribbean ◽  
Central American Isthmus

The stratigraphic record in Panama and Costa Rica preserves the biologic and climatic changes associated with the formation of a major barrier to marine migration and ocean circulation. Creating a high resolution temporal framework within which stratigraphic sections found on the Isthmus can be interpreted is fundamental to our understanding the history and importance of these units.The Isthmus contains rich marine macro- and microfaunas and floras on both the Pacific and Atlantic margins. Planktic foraminifers and calcareous nannofossils are common and often well preserved. Preliminary analysis of these fossils reveals a rich sedimentary record spanning the Late Miocene to Pleistocene. Multivariate statistical analyses of these assemblages provide environmental estimates. Unfortunately, traditional methods of biostratigraphy are limited in their ability to create a high resolution temporal framework for the region. For example, a majority of deposits analyzed can be placed in planktic foraminiferal zone N19 (early Pliocene). In order to answer paleobiologic and paleoclimatic questions one requires more precise correlations between sections and some indication of duration of sedimentation represented by various sections.In an attempt to overcome the shortcomings of traditional biostratigraphic methods, the Graphic Correlation method has been applied to selected sequences on the Central American Isthmus. Graphic correlation (GC) is a procedure by which two sequences can be compared and correlated using a wide variety of stratigraphic information simultaneously. A GC model of late Neogene planktic foraminifer, calcareous nannofossil, and paleomagnetic reversal events has been produced through compositing of more than 26 deep sea cores and ocean margin sequences. Following routine GC procedures the positions of all fossil first and last occurrences from a number of sections on the Caribbean and Pacific sides of the Central American Isthmus (Panama and Costa Rica) have been recorded. These sections have been correlated to the GC model and hence, to each other, providing a temporal framework for the Isthmus units.Selected sections were then correlated to other sequences such as near-by deep sea cores which have been analyzed for sea surface temperature and salinity to gain a better understanding of the overall paleoceanographic development of the region between 5 and 2 Ma. For example, correlation of units on the Caribbean side of the Isthmus with DSDP Site 502 indicates little to no change in sea surface temperatures during the entire time the Isthmus was reaching closure. Mid-to-high latitude sites exhibit amplification of warming with increasing latitude. The shoaling Isthmus, while having negligible effects on tropical marine temperatures, was responsible for increased meridional heat transport which resulted in a North Atlantic warming about 3 Ma. A general model for paleoceanographic changes during the time of closure will be discussed.

Time and taphonomy: Actualistic evidence for time-averaging of benthic foraminiferal assemblages

1993 ◽  
Vol 6 ◽  
pp. 34-56 ◽  
Author(s):  
Ronald E. Martin
Keyword(s):  
High Resolution ◽  
Ecosystem Management ◽  
Deep Sea ◽  
Time Averaging ◽  
Biological Processes ◽  
Exploration And Exploitation ◽  
Short Term ◽  
Resource Exploration ◽  
To Come ◽  
Paleoclimate Modelling

For more than half a century, microfossils–especially foraminifera–have been widely used as stratigraphic markers and paleoenvironmental indicators. Although increasing emphasis has been placed on their use in high-resolution paleoclimate studies, the time-scales involved in most microfossil-based stratigraphic investigations have remained relatively coarse (hundreds-of-thousands to millions of years). My intent herein is to try to come to grips with the interplay between time-averaging of benthic foraminiferal assemblages and stratigraphic resolution, and the implications for recognition of short-term physical and biological processes. These sorts of considerations deserve much closer scrutiny as the applied Earth sciences continue to move from a base of resource exploration and exploitation to one of paleoclimate modelling and ecosystem management (Martin, 1991; Corliss, 1993). The potential stratigraphic and paleoenvironmental resolution of foraminiferal assemblages is assessed using concepts derived from the age analysis of deep-sea assemblages.

scholarly journals Age Dating and the Orbital Theory of the Ice Ages: Development of a High-Resolution 0 to 300,000-Year Chronostratigraphy

1987 ◽  
Vol 27 (1) ◽  
pp. 1-29 ◽  
Author(s):  
Douglas G. Martinson ◽  
Nicklas G. Pisias ◽  
James D. Hays ◽  
John Imbrie ◽  
Theodore C. Moore ◽  
...  
Keyword(s):  
High Resolution ◽  
Deep Sea ◽  
Age Dating ◽  
Average Error ◽  
Orbital Theory ◽  
Oxygen Isotope Stratigraphy ◽  
Orbital Tuning ◽  
Isotope Stratigraphy ◽  
Degree Of Convergence ◽  
Estimated Error

AbstractUsing the concept of “orbital tuning”, a continuous, high-resolution deep-sea chronostratigraphy has been developed spanning the last 300,000 yr. The chronology is developed using a stacked oxygen-isotope stratigraphy and four different orbital tuning approaches, each of which is based upon a different assumption concerning the response of the orbital signal recorded in the data. Each approach yields a separate chronology. The error measured by the standard deviation about the average of these four results (which represents the “best” chronology) has an average magnitude of only 2500 yr. This small value indicates that the chronology produced is insensitive to the specific orbital tuning technique used. Excellent convergence between chronologies developed using each of five different paleoclimatological indicators (from a single core) is also obtained. The resultant chronology is also insensitive to the specific indicator used. The error associated with each tuning approach is estimated independently and propagated through to the average result. The resulting error estimate is independent of that associated with the degree of convergence and has an average magnitude of 3500 yr, in excellent agreement with the 2500-yr estimate. Transfer of the final chronology to the stacked record leads to an estimated error of ±1500 yr. Thus the final chronology has an average error of ±5000 yr.

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