Research Project on the manifestation of
the High Arctic Large Igneous Province (HALIP) on Svalbard
© Harmon D. Maher Jr., Dept. of Geography and Geology, University
of Nebraska at Omaha, Omaha, NE 68182-0199, U.S.A. 11/99
Fig. 1: Cretaceous sill in Carboniferous strata of Lomfjorden
area, NW Spitsbergen with about 700 m of relief.
Background on the High Arctic Large Igneous Manifestation
on Svalbard:
Major upper Cretaceous LIPs (e.g. the Kerguelen and Ontong Java Plateaus)
show Aptian magmatic peaks, and are linked to global mantle overturning
and anomalous surface environment conditions (Larson, 1991, Mahoney &
Coffin, 1997). In this context, a widespread Cretaceous thermal event evident
in the High Arctic has been identified as an LIP (Tarduno, 1998). 
Evidence for magmatic/thermal events of this age exists on Svalbard,
Franz Josef Island, adjacent shelf areas, Axel Heiberg and Ellesmere Islands,
and perhaps North
Fig. 2: Map showing present day position
of HALIP localities. Arrows shoe Cretceous position of Franz Josef Island
and Svalbard against the Lomonosov Ridge and adjacent to the Alpha Ridge.
Base map source http://www.aquarius.geomar.de/omc/make_map.html.
Greenland,
covering an area several hundred thousand square kilometers. These areas
were peripheral during the development of the Amerasian (Canada) basin and
Alpha Ridge, and together define the LIP. While very mild compression or
platform stability initially characterized Svalbard and Franz Josef, extension
characterized the Canadian Arctic. This is consistent with a large, diffuse
plume superimposed on a complex and evolving stress field. Present evidence
suggests magmatism was coeval in Svalbard and Franz Josef Land, inconsistent
with a hot spot track hypothesis. Multiple pulses of magmatic activity
could result from a deep and large plume.
This thermal/magmatic event has a distinct sedimentologic expression
on Svalbard, and elsewhere. 
Fig. 3: Stratigraphic
section of black shales of the Rurikfjellet Fm. overlain by white sandstone
of the Helvetiafjellet Fm.. This regression likely marks the first phase
of HALIP related uplift. Overlying darker colored sands have a fair amount
of volcanogenic debris, reflecting development of HALIP as a source to the
N. Section from southern Midterhuken, Spitsbergen.
Given
that much of the High Arctic LIP is either submerged, inaccessible, and
has been tectonically dispersed and eroded, the sedimentologic record may
provide important additional insight into this province.Effects attributed
to the LIP include a slow regression evident towards the top of a thick
black shale unit punctuated by locally abrupt uplift, development of a low
angle unconformity, the production of new source terranes to the north,
and more extensive diagenesis. On Spitsbergen a widespread transition from
quartz arenites to lithic arenites and feldspathic sandstones marks the
appearance of volcanic source terranes to the north and east. A Late Cretaceous
low-angle unconformity likely represents the flank of thermal doming associated
with the LIP. Towards the north associated erosion removed a minimum of
1 km and possibly several kilometers of platform cover sediments. The stratigraphic
record can be viewed in light of two pulses of activity. Better understanding
of the High Arctic LIP would help fill out the global picture of Cretaceous
LIPs.
Description of research program:
Objectives of this project are: 1) to better characterize the geochemical
signature of HALIP on Svalbard, 2) to develop a detailed model for the sedimentologic
response to HALIP, 3) to significantly refine constraints on the duration
of magmatism, and to possibly recognize pulses, 4) to test the idea of
a hot spot track origin by comparison of our results with the published
literature on Franz Josef Land (e.g. Dibner, 1998), and 5) to better characterize
HALIP in the global superplume/overturn context.
People involved:
- Harmon D. Maher Jr.: Professor, expertise in tectonics, structure
and Svalbard geology.
- Robert Shuster: Associate Professor, experise in igneous petrology
and isotope geochemistry.
- Shad Clarke: student pursuing senior thesis at UNO.
Ongoing work:
- A survey of the literature is almost complete, and an initial model
for the sedimentologic response has been presented (Maher, 1999). Svalbard's
peripheral position is optimal for working out the sedimentologic effects.
It also has become apparent that very little published trace element geochemistry
exists on the diabases. A reanalysis of 54 existing published K-Ar ages
disputes earlier contentions (Burov et al., 1975) of two pulses at 145
and 105 Ma. An initial article summarizing this work is in preparation.
- Analysis of a suite of 25 thin sections collected from the contemporaneous
Helvetiafjellet and Carolinefjellet Fms. looking for the degree and type
of volcanogenic debris is underway. Initial results are very promising.
- A proposal has been submitted to PRF to continue work.
Future work
Dependent on funding, future work will concentrate on;
1) collecting diabase samples for trace element geochemical work to try
and characterize the source character, degree of partial melting, and degree
of any contamination involved in melt production, 2) collecting sandstone
samples from appropriate stratigraphic levels for petrographic analysis
and for Nd isotope analysis, and 3) comparison of our results with those
from other parts of the HALIP.
Fig. 4: Well exposed and overturned section of Cretaceous
strata in Hornsund, and a potential sampling locality in future work.
References
- Burov, J. P., Krasilchikov, A. A., Firsov, L. V., and Klubov, B. A.,
1977, The age of Spitsbergen dolerites; Norsk Polarinstitutt Årbok
1975, p. 101-108.
- Dibner, V. D. (ed.), 1998, Geology of Franz Josef Land, Norsk Polarinstitutt
Meddelelser # 146, 190 p.
- Larson, R. L., 1991, Geological consequences of superplumes; Geology,
19, 963-966.
- Lawver, L. A. and Muller, D. R., 1994, Iceland hotspot track; Geology,
v. 22, p. 311-314.
- Mahoney, J. J. and Coffin, M. F. (eds.) 1997, Large Igneous Provinces,
Continental. Oceanic, and Planetary Flood Volcanism; American Geophysical
Union Monograph, # 100, 438 p.
- Maher, H. D. Jr., 1999, Character of Cretaceous High Arctic LIP From
a Svalbard Perspective; GSA abstracts with Programs, 31, # 7, 430.
- Tarduno, J. A., 1998, The High Arctic Large Igneous Province; International
Conference on Arctic Margins III, Celle, Germany, abstract.
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