Geology topics

M.D. Max

Publications and source records attributed to M.D. Max.

5 recordsLinked to original sources

USGS2007

Oceanic methane hydrate: The character of the Blake Ridge hydrate stability zone, and the potential for methane extraction

Oceanic methane hydrates are mineral deposits formed from a crystalline 'ice' of methane and water in sea-floor sediments (buried to less than about 1 km) in water depths greater than about 500 m; economic hydrate deposits are probably restricted to water depths of between 1.5 km and 4 km. Gas hydrates increase a sediment's strength both by 'freezing' the sediment and by filling the pore spaces in a manner similar to water-ice in permafrost. Concentrated hydrate deposits may be underlain by significant volumes of methane gas, and these localities are the most favourable sites for methane gas extraction operations. Seismic reflection records indicate that trapped gas may blow-out naturally, causing large-scale seafloor collapse. In this paper, we consider both the physical properties and the structural integrity of the hydrate stability zone and the associated free gas deposits, with special reference to the Blake Ridge area, SE US offshore, in order to help establish a suitable framework for the safe, efficient, and economic recovery of methane from oceanic gas hydrates. We also consider the potential effects of the extraction of methane from hydrate (such as induced sea-floor faulting, gas venting, and gas-pocket collapse). We assess the ambient pressure effect on the production of methane by hydrate dissociation, and attempt to predict the likelihood of spontaneous gas flow in a production situation.Oceanic methane hydrates are mineral sits formed from a crystalline `ice' of methane and water in sea-floor sediments (buried to less than about 1 km) in water depths greater than about 500 m; economic hydrate deposits are probably restricted to water depths of between 1.5 km and 4 km. Gas hydrates increase a sediment's strength both by `freezing' the sediment and by filling the pore spaces in a manner similar to water-ice in permafrost. Concentrated hydrate deposits may be underlain by significant volumes of methane gas, and these localities are the most favourable sites for methane gas extraction operations. Seismic reflection records indicate that trapped gas may blow-out naturally, causing large-scale seafloor collapse. In this paper, we consider both the physical properties and the structural integrity of the hydrate stability zone and the associated free gas deposits, with special reference to the Blake Ridge area, SE US offshore, in order to help establish a suitable framework for the safe, efficient, and economic recovery of methane from oceanic gas hydrates. We also consider the potential effects of the extraction of methane from hydrate (such as induced sea-floor faulting, gas venting, and gas-pocket collapse). We assess the ambient pressure effect on the production of methane by hydrate dissociation, and attempt to predict the likelihood of spontaneous gas flow in a production situation.

Journal of Petroleum Geology↗

USGS2006

National workshop on gas hydrates

The range of present knowledge on the subject of gas hydrates and related federal research programs was the topic of discussion at the National Workshop on Gas Hydrates, April 23–24. The intention of the meeting was to provide the impetus for an expanded and broader‐based national research program in both academia and government. Held at the U.S. Geological Survey National Center, Reston, Va., the workshop was organized by Michael D. Max, Naval Research Laboratory, Washington, D.C.; William P. Dillon, USGS, Woods Hole, Mass.; and Rodney D. Malone, U.S. Department of Energy, Morgantown Energy Technology Center, Morgantown, W.Va. The 33 attendees represented academia (33%), federal agencies (58%), and industry (9%).

Eos, Transactions, American Geophysical Union↗

USGS2002

Comment [on 'Are Proterozoic cap carbonates and isotopic excursions a record of gas hydrate destabilization following Earth’s coldest intervals?, Kennedy et al., Geology 29(5), 442-446]

We welcome the evidence noted by Kennedy et al. (2001) for strong methane excursions associated with the cessation of glacial episodes. They identify the carbon in cap carbonates overlying glacial sediments as probably being of biogenic origin and as likely having had a biogenic methane source. These authors suggest that the methane was released from gas hydrate, which we agree is likely. However, we suggest a different mechanism for that release, rather than their suggested warming event. We propose that a dominantly pressure-related mechanism would be more plausible for releasing sufficient methane from the huge gas hydrate reservoir to modify the global greenhouse and drive global warming in a geological instant.

Geology↗

USGS1999

Sea-floor methane blow-out and global firestorm at the K-T boundary

A previously unsuspected source of fuel for the global firestorm recorded by soot in the Cretaceous-Tertiary impact layer may have resided in methane gas associated with gas hydrate in the end-Cretaceous seafloor. End-Cretaceous impact-generated shock and megawaves would have had the potential to initiate worldwide oceanic methane gas blow-outs from these deposits. The methane would likely have ignited and incompletely combusted. This large burst of methane would have been followed by longer-term methane release as a part of a positive thermal feedback in the disturbed ocean-atmosphere system.

Geo-Marine Letters↗

USGS1988

Seismic anisotropy in mylonites: An example from the Mannin Thrust Zone, southwest Connemara, Ireland

Mylonites associated with the Mannin Thrust zone of southwesternmost Connemara formed when the high-grade metamorphic rocks typical of most of the Connemara massif were thrust to the southeast over low metamorphic grade (low greenschist facies?) acid volcanics and volcaniclastic sediments, while being metamorphosed in the epidote-amphibolite facies. Triaxial and biaxial ultrasonic velocity measurements of mylonite specimens from a 240 m borehole have established that there is significant seismic anisotropy up to about 11% when comparing velocities perpendicular and parallel to the foliation. This would ultimately lead to a reflection coefficient of about 0.02 when comparing the mean "isotropic" seismic velocity with that perpendicular to the foliation. The finely striped, discontinunous mineral lithons that define mylonitic foliation, but which form no real and continuous surfaces, could interact with seismic energy to produce "reflections" that do not relate to lithological contacts within the rocks but to a tectonically induced, orientated acoustic impedance. However, the results support the work of others in suggesting that on its own the fabric would not produce the high amplitude reflections observed on deep seismic lines and other mechanisms need to be investigated.

southwest Connemara↗