Bottom‐simulating reflections and geothermal gradients across the western Svalbard margin

• Published in: Terra Nova
• Main Authors: Vanneste, Maarten, Guidard, Stéphanie, Mienert, Jürgen
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2005
• Subjects: Knipovich Ridge; Molloy; Svalbard; Svalbard margin
• Online Access: http://dx.doi.org/10.1111/j.1365-3121.2005.00643.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1365-3121.2005.00643.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-3121.2005.00643.x

Abstract Seismic reflection data reveal prominent bottom‐simulating reflections (BSRs) within the relatively young (<0.78 Ma) sediments along the West Svalbard continental margin. The potential hydrate occurrence zone covers an area of c. 1600 km 2 . The hydrate accumulation zone is bound by structural/tectonic features (Knipovich Ridge, Molloy Transform Fault, Vestnesa Ridge) and the presence of glacigenic debris lobes inhibiting hydrate formation upslope. The thickness of the gas‐zone underneath the BSR varies laterally, and reaches a maximum of c. 150 ms. Using the BSR as an in‐situ temperature proxy, geothermal gradients increase gradually from 70 to 115 °C km −1 towards the Molloy Transform Fault. Anomalies only occur in the immediate vicinity of normal faults, where the BSR shoals, indicating near‐vertical heat/fluid flow within the fault zones. Amplitude analyses suggest that sub‐horizontal fluid migration also takes place along the stratigraphy. As the faults are related to the northwards propagation of the Knipovich Ridge, long‐term disturbance of hydrate stability appears related to incipient rifting processes.