Scientific
Prospectus
Cruise
MARSIBAL-1
Geological & Geophysical Survey in the Alboran and
South-Balearic margins & basins
R/V
Professor LOGACHEV (19-28 July 2002)
Introducción
The
MARSIBAL-1 cruise, TTR 12- Leg 3, applies to the coordinated
Spanish project REN2001-3868-CO3 (R & D National Plan
of the Ministry of Science and Technology) "Integrated
Geological and Geophysical Studies in Southern Iberia
Margins and Sedimentary Basins: Linking deep-seated and
shallow -seated process in the Alboran Sea and its connection
to the Atlantic" (MARISBAL Project) (Coordinator
Prof. Dr. Menchu Comas). Within this project, TTR-12 Leg
3 will be carried to address scientific targets for survey
of sub-projects REN2001-3868-CO3-01 (PI: Prof. Dr. Menchu
Comas) and REN2001-3868-CO3-03 (PI: Dr. Belen Alonso).
Furthermore, the cruise is also participated by project
REN2000-0798 (R & D National Plan of the Ministry
of Science and Technology) "Paleoclimate Reconstruction
in the Western Mediterranean During the Last 20.000 years"
(PI: Francisca Martinez-Ruiz).
Prime
thematic objective of the MARSIBAL-1 cruise deals with
the understanding of the dynamics of Earth's interior
and Earth's environment accounting for lithosphere's evolution
and present-day lithosphere's structure, and for surface
processes shaping the margin, respectively.Scientific
objectives from Subproject REN2001-3868-CO3-01 address
tectonic-related processes leading to crustal deformation
and basin architecture, active tectonics and faulting,
deep to shallow seismicity, present-day plate kinematics,
and related subsurface structures and seafloor morphology.Scientific
objectives from Subproject REN2001-3868-CO3-03 adress
sedimentary processes and deposition during the Plio-Quaternary,
basin architecture, sedimentary systems, gravity and turbidite
facies, erosion processes and mass transfer, sediment
instability and sedimentary-induced sea floor morphology.The
scientific objective from Subproject REN2000-0798 addresses
climate changes in the westernmost Mediterranean during
the last 20,000 years, involving the ocean & atmosphere
response, the sedimentary regime and the biosphere response
(biological productivity).
This
cruise will contribute to the sponsor projects with a
process-oriented, multidisciplinary, integrated geological
and geophysical approach (mud volcanism & fluid venting,
sedimentary systems, basin stratigraphy, tectonics, and
paleoceanography) on selected sites of the Alboran and
South Balearic Basins to better understand the late Cenozoic
to present-day tectonic, sedimentary and climatic history
of the SE Iberian margins.Expected
results would have implications for oil exploration, high-resolution
marine geology mapping, slope instabilities and geotechnics,
seismic risk, and coastal-line fluctuations.Furthermore,
the data and results from TTR 12 Leg3 aim to providing
field and analytical data set to fulfill strategic purposes,
and site survey requirements, to support future drilling
proposals in the westernmost Mediterranean basins toward
the "Integrated Ocean Drilling Program" (IODP).
Main
scientific objectives:
1)
Mud volcanoes: Sea floor expression, volcanic material
and shallow structures.
The
notable mud-diapiric province recognized in seismic profiling
in the West Alboran Basin is formed of over-pressured
shales of early Miocene (Burdigalian) age. The mud diapirism
is related to middle Miocene extensional processes. Intensive
diapirism resumes by post-Messinian times and continue
till the Holocene then reaching the sea floor as mud volcanoes.
Mud volcano survey for TTR-12 in the West Alboran Basin,
is a continuation of researches from TTR-9 BASACALB cruise
(1999) in which two mud volcanoes (Granada & Marrakesh)
were discovered and sampled by gravity cores in the southern
Alboran basin. This survey aims now are to identify and
characterize mud volcanoes and associate structures in
the northern West Alboran Basin and revisit the mud volcanoes
field in the southern West Alboran Basin to complete the
TTR 9 survey and to sample probable "cap-rock"
observed in TV images and by diving with the submarine
"CYANA" at the top of a mud-volcano. It is expected
to better identify and dating, the mud-volcano material,
with hopes to be able to correlate the diapiric mud with
the basal Unit VI of the Alboran sedimentary cover. There
remain many interesting questions in the field of mud
volcanism and fluid flow through the seafloor in the Westernmost
Mediterranean regarding mud eruptions, and associate phenomena,
and on the nature of the tectonic setting of such mud
volcanoes.
2)
Active tectonics in the Carboneras-fault system: Shallow
structures & seafloor fault-expression in seismically
active sectors.
The
Carboneras-fault system encompasses sites of seismogenic
fault development (active tectonics) related to recent
episodes of strike-slip and extensional or compressional
faulting occurred until the Holocene. As high-resolution
swath bathymetry and side scan sonar/ back-scattering
records have imaged it (SIMRAD mosaic and TOBI images
taken during the HITS cruise, BIO HESPERIDES - 2001),
these faults deform the sea floor. We plan to complete
the record of seismogenic faults in the Almería
margin to better understand the present-day tectonic behavior
of the eastern South Iberian margins. Some of these faults
locate above shallow earthquakes epicenters. Integrated
studies of high-resolution seismic reflection data (to
be acquired from this cruise), and previous data will
be used for mapping the 3D geometry and offset of structures
(transfer, en echelon, branching faults y splay faults),
and to determine the fault kinematics and the tectonic
control on seafloor morphology. We also plan for further
studies to integrate onshore and offshore data through
structural sections crossing the coastal line.
3)
The Almería Turbidite System and the Almería
canyon: submarine valleys morphology (canyons, channels
and levees), mass flows and turbidite facies pattern.
The
Almeria Turbidite System represents an exceptional scenario
to establish a detailed architectural and morphological
study, and quantification, of the margin-basin depositional
behavior in the Almeria margin. We aim to define the morphological
features (meanders, levees, lobes. etc) of submarine valleys
(canyon and turbidite channels) transporting sediments
from the platform to the basin, as well as the bed forms
and facies pattern of sediment accumulation from the channeled
area to the base of the slope. Our approach focus to determine
the factors and sedimentary processes (mass, flow, turbidite
currents, tectonic versus eustatic and sedimentary instability),
that control the evolution of the turbidite system. We
plan also for futhter reseearch to modelling the turbidite
system by defining its architecture and dimension, turbidite
facies associations, external and internal source area,
and sedimentary activity in the system. This approach
will allow to compare the Almeria Turbidite System with
other counterparts in the South Iberian margin to better
understand the source-to-sink regional processes and patterns.
4) Holocene pelagic sediments: Paleoclimate
reconstruction in the western Mediterranean during the
last 20,000 years (Gravity coring from West Alboran to
South balearic basins).
Coring
in the Alboran Sea and South-Balearic basins is aimed
to high-resolution analysis (bio- & chrono-stratigraphy,
geochemical and isotopic studies) on sediment cores to
characterize the climate during the last 20,000 years
when significant climate changes occurred. Paleoclimate
reconstruction will attain the last glacial, the Younger
Dryas and climate changes involving the deposition of
the most recent sapropel (S1). These changes encompass
ocean circulation changes, atmosphere input (eolian fluxes),
and sedimentary response, as well as the fluctuations
on biological productivity. High sedimentation rates in
the Alboran Sea basin will provide an excellent resolution
for the interpretation of regional and global climate
changes during this time.
5)
Residual seamounts in the Almería and Cartagena
margins: Nature and age.
Residual
structural or morphologic highs in the Almería
margin are known from existing seismic reflection (MC
& SC) data and have been imaged by ecosounders records
from previous survey; nevertheless some of them have been
dredged in the past with scarce or no recovery and few
information is available on lithologies forming these
seamounts. From existing data we know the highs can be
formed of volcanic or metamorphic rocks, either of self-temperate
carbonate deposits. Sampling these seamounts by the TV-guided
grab is aimed to know the nature -igneous, metamorphic,
or sedimentary- and rock age of these acoustic basement
highs. As known onshore Iberia, volcanic rocks forming
submarine volcanic edifices may range in nature from alkaline
and calc-alkaline basalt to rhyolite (Early Miocene and
late-Serravallian-to-Tortonian, up to 9 Ma) to Lamproites,
shoshonitic lavas (9-4.5 Ma) and alkali basalts (6 -1.5
Ma). Metamorphic complexes belonging to the Alboran Crustal
Domain (the Alpujarride or Nevado-Filabride complexes
of the Betic Cordillera) form the basement of the Alboran
Basin in the Iberian margin, as demonstrate by ODP leg
161, and may form outcropping or sub-outcropping horsts.
Late Pliocene (2.40 Ma) to present-day sedimentation on
the Almería margin includes carbonate, mixed carbonate
and siliciclastic deposits. Carbonate and mixed carbonate-siliciclastic
sediments accumulate in areas sheltered from direct terrigenous
input, as can be expected laid-down on residual highs
in the margin. Organisms living on the platform and their
derived skeletal particles are the typical components
of bryomol and rhodalgal facies that characterize temperate
carbonates. We hope to have the chance for sampling carbonates
on the tops of some seamount. The study of the temperate
carbonate and mixed carbonate-siliciclastic facies will
illustrate about sea level changes and climatic changes
in the South Iberian margins.
Survey
Operations
Methods
and equipment:
•Hull-mounted
3.5 kHz profiler to be routinely used, with continuous
paper output and selective digital recording.
•MAK
1 deep-towed sidescan sonar operating at 30 kHz (2 km
swath width) and 100kHz (1 km swath width), with 7.5
Khz subbotton penetrating echosounder and digital recording.
•OKEAN
10 kHz long-range sidescan sonar system.
•High
resolution single channel seismic reflection profiling:
3.5 or 3.5 x 2-liter air gun; streamer consisting in
7.5 m long active single section with 16 hydrophones.
Sample interval of 1ms and record length of 2-3 seconds
is proposed.
•DG-1
TV-guided grab (maximum sample volume of 0.4m3 for soft
sediments), & video recording (Hi-Fi- Video 8 format)
•
Gravity coring: 6 m long, 1500 kg gravity core with
internal diameter of 12.7 cm.
(Figura
1)
Proposed
Survey
The
whole region of survey is located between 35,8 N - 37,8
N latitude and 5W - 0 longitude in the Alboran and South
Baleric seas. Four main sectors for multi-equipment survey
have been selected in the Albora Sea, and additional survey
will be conducted on selected sites in the South Balearic
Sea (Sector 5 and pelagic-sediment core sites)
Sector
1 (Scientific Objective 1):
The
aim in this sector is to collect information around two
probable mud volcanoes, imaged from an existing single
channel seismic profile, in the northern mud-diapir province
of the West Alboran basin.
•The
survey will be conducted by a first reconnaissance based
on 5 kHz sub-bottom profiles, a mosaic of OKEAN-long
range sidescan sonar records and simultaneous high resolution
seismic in the sector.
•If OKEAN resulting data
are suitable, we will continue the survey by acquiring
MAK I sonographs across the top of mud volcanoes (LR
Mode at a frequency of 30 kHz)
•We would plan for TV-controlled
GRAB and/ or coring on the top pf the mud volcanoes
if its seafloor expression, were considered interesting
for. Places/ number of sampling to be selected according
imaged data.
Sector
2 (Scientific Objective 1):
The
aim in this sector is to enlarge and complete the survey
conducted for TTR- 9 Leg 3 (Sector A) on the mud volcano
field in the Morocoan margin of the West Alboran basin.
We plan to enlarge the OKEAN- seismic profiling survey
area to reach the Daka mud volcano (showed in MCS line
Conrad 827), and to better image from high-resolution
sonographs the tops of the mud volcanoes. Also we to sample
the mud volcano material and related rocks.
We
will conduct:
• OKEAN-long range sidescan
sonar and high-resolution seismic profiles along selected
tracks in the sector.
• MAK I (LR Mode at a frequency
of 30 kHz) sonographs on across selected mud volcanoes
• Sampling on the top the
Granada and others (the Daka mud volcano?) mud volcanoes
by TV-controlled GRAB and coring. Places/ number of
sampling will be selected according imaged data.
Sector
3 (Scientific Objective 3):
Three
alternative sub-sectors have been identify for survey
in this sector. Order of priority is Box 1, Box-2 and
Box-3, working on these sub-sectors will be completed
as time allows.
Box
1:
This
box is focused on the lower sector of the Almeria Turbidite
System, which has not been studied in detail up to now.
In particular, we will pay attention to the distal Almeria
Channel in order to study:
•The
levee-channel pathway
•The erosive and depositional
features on the talweg and internal/external levees
•Identification of channel-lobe
transition area
•Channel mouth sedimentary
features
•Pattern and facies of the
distributary channels
This
study will be carried out by combining analysis of different
acoustic data: 1) sonographs (MAK I side scan sonar);
2) 5 kHz sub-bottom profiles and 2) single-beam echo sounder.
The MAK I side scan sonar will use in LR Mode at a frequency
of 30 kHz, and with a swath width of 2 km.
Box
2:
This
box is focused on the right margin of the Almería
channel in order to study the sediment waves identified
previously with sparker and air gun profiles. The specific
objectives are:
•Define
the morphologic parameters of the sediment waves: wave
height, wavelength, plan-view pathway, cross-section
shape,...
•Define the area covered
by the sediment waves and their morphological spatial
trends
•Determine the genesis of
the sediment waves: bottom currents or turbidity currents.
If they are turbidity current sediment waves, then characteristics
of the turbidite flow currents will be calculated.
This
study will be carried out by sonographs (MAK I side scan
sonar) and 5 kHz sub-bottom profiles. The MAK I side scan
sonar will use in LR mode at a frequency of 30 kHz and
with a swath width of 2 km.
Box
3:
This
box is focused on the eastern sector of Almería
base of slope in order to study to mass-movement features,
which has been previously identify with the TOBI system
in the slope of Sabinar Bank. The specific objectives
are the following:
•Identify
surficial morphologic features
•Measure scale and run out
of the slide masses
•Determine the type of internal
acoustic facies
•Define type of mass-movement
deposit and their lateral relationships
This
study will be carried out by sonographs (MAK I side scan
sonar) and 5 kHz sub-bottom profiles. The MAK I side scan
sonar will use at a frequency of 30 kHz and with a swath
width of 2 km.
Sector
4 (Scientific Objective 2 and 5):
Survey
in this sector is aimed to complete data and enlarge the
survey conducted by the HITS cruise (BIO HESPERIDES, 2002),
to the east of TOBI and SIMRAD bathymetry images.
We
will conduct:
•5 kHz sub-bottom profiles
• Single-beam echo sounder.
•High resolution single channel
seismic reflection profiling: 3.5 or 3.5 x 2 liter air
gum, 2-3 second penetration.
• DG-1
TV-guided grab & video recording will be done on
the top of the Chella bank, at sites according to TOBI
data.
Sector 5 (Scientific Objective2
& 5)
Survey
in this sector is aimed to complete data and enlarge the
survey conducted by the TECALB cruise (BIO HESPERIDES,
2000). We plan to investigate a NE-SW fault escarpment
at the ocean- continent boundary in the South Balearic
margin, and the nature of the Aguilas seamount.
We
will conduct:
• Preliminary survey with
the 5 kHz sub-bottom profiler.
• Video recording and DG-1
TV-guided grab sampling will be conducted on suitable
rock-outcrops at the food of the escarpment in order
to recover hard-rock pieces.
• If time allow, we would
plan for imaging the fault escarpment by MAK I (LR Mode
at a frequency of 30 kHz) sonographs.-
•Samples will be described
onboard, and sub-sampling will be done as necessary
•Specific objectives of further
onshore research will depend upon the recovered lithology
(volcanic, metamorphic or sedimentary).
Gravity Coring (Scientific Objective
4)
•
Gravity cores are to be open and cut onboard.
• One half will be measured
and described on desk, paying attention to changes in
lithology, color and sedimentary structures, and further
core measurements as available onboard.
• Sampling of this half will
be for preliminary biostratigraphy (foram & nanno)
and sedimentological studies.
• All color will be referred
to Munsell Color Chart. The other half will be stored
in refrigerated camera for later onshore studies.
Specific
objectives of further research are focused on:
•Biostratigraphy
and cronostratigraphy.
•Sea surface temperatures
(SSTs) and salinity in order to approach circulation
patterns
•Paleoproductivity changes.
•Pale-oxygen conditions in
water column and sediments at time of deposition.
•Responses of benthic and
plank tonic communities to climate changes.
•Sedimentary regime: with
special focus on fluvial and eolian input and sources
areas.
•Ciclostratigraphy.
GRAB
sampling on Seamounts (Scientific Objective 5)
We
plan to investigate the lithology on the top of two seamounts
in the eastern Almeria margin (the Sabinal and Pollux
Seamounts) , and if possible in the submarine prolongation
of Cabo de Gata.
We
will conduct:
• Preliminary survey with
the 5 kHz sub-bottom profiler
•Single-beam echo sounder
record.
• DG-1 TV-guided grab sampling
& video recording on the top of suitable seamount
escarpments .
•Samples will be described
onboard, and sub-sampling will be done as necessary
•Specific objectives of further
onshore research will depend upon the recovered lithology
(volcanic, metamorphic or sedimentary).
Spanish Team Participants:
Projects
REN2001-3868.CO3-03 & REN2000-0798. Instituto Andaluz
de Ciencias de la Tierra (CSIC & University of Granada),
Granada (Spain):
•
Dr Menchu Comas, Research professor (IACT), Co-Chief
Scientist, mcomas@ugr.es
•Dr.
Francisca Martinez-Ruiz, Researcher (IACT), fmruiz@ugr.es
•
Dr. Juan-Ignacio Soto, Assistant professor (Depto. Geodynamic,
Univ. Granada -IACT), jsoto@ugr.es
•
Dr. Francisco Rodriguez-Tovar, Assistant professor (Depto
Strati & Paleont, Univ.Granada), frtovar@ugr.es
•Francisco
J. Jiménez-Espejo, PhD student (IACT), fjjspejo@ugr.es
•Guillermo
Marro, PhD student (IACT), (Spain) gmarro974@hotmail.com
•
Asrarur Talukder, PhD student (IACT), (Bangladesh) taluker@ugr.es
•
Manuel Roman-Alpiste, Technician (IACT), (Spain) mjroman@ugr.es
•Invited:
Adriano Mazzini, PhD student, University of Aberdeen
(UK) a.mazzini@abdn.ac.uk
•Observer:
Mr. Abdellaoui Benyounes, Inst. Nat. Rechearche Halieutique-l'INRH,
Nador, Morocco
Project
REN 2001-3868.CO3-03. Instituto de Ciencias del Mar-ICM,
CSIC Barcelona (Spain):
•
Ferran Estrada, PhD researcher (ICM), festrada@icm.csic.es
•
Dr. Mª Jose Jurado, Researcher (Instituto Ciencias
de la Tierra- IJA), CSIC- Barcelona mjjurado@ija.csic.es
•
Marta Molinos, PhD student (ICM) martams@icm.csic.es
•Invited:
Cesar Guijarro, Telefonica de España/Cables Submarinos,
Madrid, cesar.guijarrollanos@telefonica.es
