scholarly journals Low Heat Flow at Shallow Depth Intervals: Case Studies from Belarus

2021 ◽  
Vol 4 (1) ◽  
pp. 79-84
Author(s):  
Vladimir Ignatievich Zui
Keyword(s):  
Heat Flow ◽  
Water Exchange ◽  
High Heat ◽  
Flow Density ◽  
Western Slope ◽  
East European ◽  
Voronezh Anteclise ◽  
Groundwater Circulation ◽  
Loose Sediments ◽  
Platform Cover

The territory of Belarus belongs to the western part of the Precambrian East European Platform. Its heat flow pattern is representing by alternating low and high heat flow anomalies. An overwhelming majority of heat flow determinations and in general of geothermal observations in Belarus were fulfilled in boreholes finished in the platform cover. Within the Belarusian Anteclise, Orsha Depression, western slope of the Voronezh Anteclise their bottom holes are typically within the zone of active water exchange, where the groundwater circulation sufficiently influences on recorded thermograms. For instance, observed heat flow density for a number of studied boreholes is low and ranges on average from 15–20 until 35–40 mW/m2 within the Orsha Depression. In a number of studied holes in the northern part of the structure, its values are surprisingly low. They are observed within upper horizons of the zone of active water exchange with pronounced groundwater circulation. Permeable rocks within the geologic section comprise the platform cover with a number of freshwater intervals. Their base is spread here up to depths of 150–250 m. The most of heat flow observations within this area were studied in boreholes which depths is only 200–300 m, sometimes less, as deeper wells are seldom within this geologic structure. Groundwater circulation within loose sediments cools them, most of thermograms here have a concaved shape to the depth axis. As a rule, heat flow values are sufficiently lower in a number of intervals in boreholes finished in the freshwater zone, relatively to the heat flow observed within deeper horizons of the platform cover. In some of studied boreholes, the observed heat flow is as low as 5–15 mW/m2. In most cases it has a tendency to stabilise only at intervals deeper than 600–800 m. It is the main reason for observed low heat flow zones.

scholarly journals GEODYNAMICS

GEODYNAMICS ◽  
2011 ◽  
Vol 2(11)2011 (2(11)) ◽  
pp. 147-149
Author(s):  
R. I. Kutas ◽  
Keyword(s):  
Heat Flow ◽  
Tectonic Evolution ◽  
Thermal Field ◽  
Pannonian Basin ◽  
High Heat ◽  
Flow Density ◽  
Heat Flow Density ◽  
East European ◽  
Geodynamic Processes ◽  
Outer Carpathians

Heat flow density changes from 35-40 mW/m2 in the south-western part of East-European Craton and the Carpathian foredeep to 50-60 mW/m2 in the Outer Carpathians and to 80-120 mW/m2 in the Pannonian basin. Several levels of thermal field reflect main stages of tectonic evolution and feature of lithosphere structure. High heat flow anomaly was created by Cenozoic geodynamic processes related to collision of the European plate and Alcape microplate.

scholarly journals Terrestrial heat flow versus crustal thickness and topography – European continental study

2019 ◽  
Vol 2 (1) ◽  
pp. 17-21 ◽  
Author(s):  
Jacek Andrew Majorowicz ◽  
Marek Grad ◽  
Marcin Polkowski
Keyword(s):  
Heat Flow ◽  
Barents Sea ◽  
Moho Depth ◽  
Flow Density ◽  
Ural Mountains ◽  
The West ◽  
East European ◽  
The North ◽  
Small Depth ◽  
Paleoclimatic Correction

The relation between heat flow, topography and Moho depth for recent maps of Europe is presented. Newest heat flow map of Europe is based on updated database of uncorrected heat flow values to which paleoclimatic correction is applied across the continental Europe (Majorowicz and Wybraniec 2010). Correction is depth dependent due to a diffusive thermal transfer of the surface temperature forcing, of which glacial–interglacial history has the largest impact. This explains some very low uncorrected heat flow values of 20–30 mW/m2in shallow boreholes in the shields, shallow basin areas of the cratons, and in other areas including orogenic belts where heat flow was likely underestimated due to small depth of the temperature logs. New integrated map of the European Moho depth (Grad et al 2009) is the first high resolution digital map for European plate, which is understood as an area from Ural Mountains in the east to mid-Atlantic ridge in the west, and Mediterranean Sea in the south to Spitsbergen and Barents Sea in Arctic, in the north. For correlation we used the following: onshore heat flow density data with palaeoclimatic correction (5318 locations), topography map (30x30 arc seconds, by Danielson and Gesch 2011) and Moho map by Grad et al (2009), providing longitude, latitude and Moho depth (with resolution of 0.1 degree). Analysis was limited to locations for which datasets were available. The area of continental Europe has been divided into two large domains: Precambrian East European craton and Palaeozoic Platform of the West Europe. In addition, two smaller areas were considered, corresponding to Scandinavian Caledonides and Anatolia. The results obtained reveal significantly different correlations between Moho depth, elevation and heat flow for these regions. For each region detailed analysis of these relations in different elevation ranges are presented. In general, it is observed that Moho depth is more significant for heat flow than elevation. Depending on the region and elevation range, heat flow value is up to two times larger than Moho depth, while relation of heat flow to elevation has much more variability.

scholarly journals Geothermal field of the transition area between the Anatolian Plate and the East European Platform

2019 ◽  
pp. 133-148
Author(s):  
Mansouri Far Siamak
Keyword(s):  
Heat Flow ◽  
Black Sea ◽  
Eastern Mediterranean ◽  
Eastern Mediterranean Region ◽  
The Black Sea ◽  
Flow Density ◽  
Heat Flow Density ◽  
Western Turkey ◽  
East European ◽  
East Anatolia

Heat flow data from the Eastern Mediterranean region indicates an extensive province of low heat flow, spreading over the whole basin of the Mediterranean to the east of Crete (Levantine Sea), Cyprus, and Northern Egypt. Surface geology of East Anatolia is complex because of recent active tectonic and volcanic activity. The region is composed of major tectonic units of Pontides, the Anatolid-Tauride Belt and Bitlis Suture Zone, North and East Anatolian faults. Ophiolitic and young volcanic rocks can be observed in many parts of East Anatolia. The Black Sea is surrounded by the Alpine-Himalayan Orogenic Belt of Crimea, Greater Caucasus, Pontides, Rhodope-Stranja Massif, Eastern Srednegorie, North Dobrogea and older tectonic units of different origins and ages such as the Precambrian East European Craton, Moesian Platform, Istanbul Zone and Adzhar-Trialet Folded System. Low heat flow density dominates in the Black Sea. The lowest (less•30 mW/m2 ) values have been recorded in central parts of the Western and Eastern Black Sea basins with maximal sedimentary thickness. Geothermal studies within the territories of Ukraine have been under way since sixties. Many important features of the thermal field remain unstudied. This applies in particular to the Ukrainian Shield and to the southern part of the Carpathian region. In general, the territory of Alpine folding within Turkey, Marmara and Aegean seas, Caucasus is characterized by high heat flow. The anomaly of its highest values (above 100 –150 mW/m2 ) exists within western Turkey, where tectonic conditions of extension prevail and underground steam is used to produce electricity. Three heat flow density profiles crossing the studied region and heat flow map were compiled.

On the effects of thermal properties structure and water bottom temperature variation on temperature gradients in lake sediments

1986 ◽  
Vol 23 (9) ◽  
pp. 1257-1264 ◽  
Author(s):  
K. Wang ◽  
P. Y. Shen ◽  
A. E. Beck
Keyword(s):  
Heat Flow ◽  
Temperature Variation ◽  
Stratified Medium ◽  
Depth Interval ◽  
Flow Density ◽  
Detailed Knowledge ◽  
Bottom Temperature ◽  
Temperature Variations ◽  
Density Values ◽  
Finite Sum

In heat flow determinations, it is customary to treat the surface temperature variation as a finite sum of Fourier components. The medium is assumed to be homogeneous or horizontally stratified with each layer having a constant conductivity and diffusivity. This allows the effect of each periodic component to be calculated analytically. We extend this formulation to include cases where thermal conductivities in some layers of a stratified medium may vary linearly with depth as have been found in the sediments of some continental lakes. The application of this formalism to temperature measurements in Lake Greifensee and Lac Leman shows that even with excellent records of bottom temperature variations over several years, failure to take into account the conductivity variation leads to errors as high as 20% in heat flow density values, depending on the depth interval used. The combined effects of lack of detailed knowledge of conductivity structure and the use of too short and (or) inaccurate records of bottom temperature variations, leading to very significant errors, are also discussed, with particular reference to the problems arising from a lack of recognition of the existence of nonannual terms in the bottom temperature variation and the use of probes that do not penetrate the sediments deeply enough.

High heat flow at the SW passive margin of the Gulf of California

Terra Nova ◽  
2021 ◽  
Author(s):  
Rosa Maria Prol‐Ledesma ◽  
Juan Luis Carrillo De La Cruz ◽  
Marco‐Antonio Torres‐Vera ◽  
Alejandro Estradas‐Romero
Keyword(s):  
Heat Flow ◽  
Gulf Of California ◽  
High Heat ◽  
Passive Margin ◽  
High Heat Flow

A heat-flow reconnaissance of southeastern Alaska

1985 ◽  
Vol 22 (3) ◽  
pp. 416-421 ◽  
Author(s):  
J. H. Sass ◽  
L. A. Lawver ◽  
R. J. Munroe
Keyword(s):  
Heat Flow ◽  
Plate Boundary ◽  
Thermal Spring ◽  
High Heat ◽  
Transform Fault ◽  
High Heat Flow ◽  
Queen Charlotte Islands ◽  
Late Tertiary ◽  
The Mean ◽  
Strain Heating

Heat flow was measured at nine sites in crystalline and sedimentary rocks of southeastern Alaska. Seven of the sites, located between 115 and 155 km landward of the Queen Charlotte – Fairweather transform fault, have an average heat flow of 59 ± 6 mW m−2. This value is significantly higher than the mean of 42 mW m−2 in the coastal provinces between Cape Mendocino and the Queen Charlotte Islands, to the south, and is lower than the mean of 72 ± 2 mW m−2 for 81 values within 100 km of the San Andreas transform fault, even farther south. This intermediate value suggests the absence of significant heat sinks associated with Cenozoic subduction and of heat sources related to either late Cenozoic tectono-magmatic events or significant shear-strain heating. At Warm Springs Bay, 75 km from the plate boundary, an anomalously high heat flow of 150 mW m−2 can most plausibly be ascribed to the thermal spring activity from which its name is derived. At Quartz Hill, 240 km landward of the plate boundary, a value of 115 mW m−2 might indicate a transition to a province of high heat flow resulting from late Tertiary and Quaternary extension and volcanism.

scholarly journals High heat flow in the trans-Hudson Orogen, Central Canadian Shield

1996 ◽  
Vol 23 (21) ◽  
pp. 3027-3030 ◽  
Author(s):  
L. Guillou-Frottier ◽  
C. Jaupart ◽  
J. C. Mareschal ◽  
C. Gariépy ◽  
G. Bienfait ◽  
...  
Keyword(s):  
Heat Flow ◽  
High Heat ◽  
Canadian Shield ◽  
High Heat Flow

scholarly journals Gold in Irish Coal: Palaeo-Concentration from Metalliferous Groundwaters

Minerals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 635
Author(s):  
Liam A. Bullock ◽  
John Parnell ◽  
Joseph G.T. Armstrong ◽  
Magali Perez ◽  
Sam Spinks
Keyword(s):  
Heat Flow ◽  
Low Temperature ◽  
Precious Metals ◽  
High Heat ◽  
Selenium Content ◽  
Foreland Basins ◽  
High Heat Flow ◽  
South Wales ◽  
First Time ◽  
Very High

Gold grains, up to 40 μm in size and containing variable percentages of admixed platinum, have been identified in coals from the Leinster Coalfield, Castlecomer, SE Ireland, for the first time. Gold mineralisation occurs in sideritic nodules in coals and in association with pyrite and anomalous selenium content. Mineralisation here may have reflected very high heat flow in foreland basins north of the emerging Variscan orogenic front, responsible for gold occurrence in the South Wales Coalfield. At Castlecomer, gold (–platinum) is attributed to precipitation with replacive pyrite and selenium from groundwaters at redox interfaces, such as siderite nodules. Pyrite in the cores of the nodules indicates fluid ingress. The underlying Caledonian basement bedrock is mineralised by gold, and thus likely provided a source for gold. The combination of the gold occurrences in coal in Castlecomer and in South Wales, proximal to the Variscan orogenic front, suggests that these coals along the front could comprise an exploration target for low-temperature concentrations of precious metals.

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