Gerald M. Friedman

Deep-burial diagenesis: Its implications for vertical movements of the crust, uplift of the lithosphere and isostatic unroofing—A review

Abstract Various techniques of study of strata exposed at the surface in undeformed areas of the Appalachian Basin and Ozark Done, imply that these strata have been heated to temperatures that suggest a former great depth of burial. The data reveal that the strata have been much more deeply buried than previously thought. If such former deep burial has taken place, then subsequent uplift and erosion must also have taken place to bring these formerly deeply buried strata to the present land surface. Unexpectedly large amounts of uplift and erosion, ranging from 4.3 to 7 km, have re-exposed these formerly deeply buried rocks. This leads to the surprising conclusion that isostatic unroofing has stripped off thick sections of strata whose presence was previously unsuspected. Therefore, the lithosphere, in its isostatic unroofing of thick sequences of sedimentary strata, has undergone much larger vertical motions than many geologists had previously estimated. Case histories in this review include strata of the Silurian of the Northern Appalachian Basin and of the Ordovician of the Ozark Dome, which reached interpreted maximum burial depths of 5 and 4.3 km, respectively; Devonian strata in the Catskill Mountains of New York imply a former depth of burial of ∼ 6.5 km. Lower Ordovician carbonate sequences of the Northern Appalachian Basin imply a depth of burial in excess of 7 km; Middle Ordovician strata from the same basin signify a depth of burial of approximately 5 km; and Devonian strata, a paleodepth of 4.5–5 km. Such former great depths of burial of undeformed strata, which are now exposed at the surface, reflect large-scale vertical movements of the crust and uplift of the lithosphere. These drastic changes represent isostatic unroofing with widespread implications for paleogeography of a kind unrecognized at present.

Erratum to: Dissolution-collapse breccias and paleokarst resulting from dissolution of evaporite rocks, especially sulfates

Pages 53–63 of Gerald M. Friedman’s paper titled Dissolution-collapse Breccias and Paleokarst Resulting From Dissolution of Evaporite Rocks, Especially Sulfates, v. 12, no. 1, Carbonates and Evaporites, should be read in the following order of pages: 53,57,55,56,54,58–63.

Rapidity of marine carbonate cementation — implications for carbonate diagenesis and sequence stratigraphy: perspective

Abstract Lithification is a rapid process, but how rapid is rapid? A year after one of my visits to Joulters Cay (Bahamas) I found a sardine can from my previous visit. The cementation of carbonate particles in and around the can was surprising. 382 g of ooids and skeletal material had filled the can and lithified therein, or had become cemented to the outside of the can. The rapidity of marine carbonate cementation implies that during highstand of sea level shallow-water platform carbonate sediments are subject to marine lithification which retards erosion. This conclusion is at variance with that of other workers who rely on freshwater cementation during lowstands to generate cement which retards reworking. Clearly the historical debate over highstand versus lowstand of shallow-water marine carbonates is not yet over.

The sedimentology of the Dead Sea

The Dead Sea, one of the most saline lakes in the world, has recently (1979) undergone a major change in its hydrologic regime resulting in the mixing of its once stable meromictis. Prior to, and during this change, a sedimentologic study was undertaken to document the types of sediments in the Dead Sea, covering the entire western half of the lake, to refine ideas on the formation of the evaporite sediments and to explain the distribution of sediments in the Dead Sea.Study of the mineralogy and particle-size distribution of sediments of the Dead Sea reveals that, of the primary minerals, gypsum concentrates in the coarse silt and sand-size fractions whereas aragonite falls in the clay and fine silt fractions. The predominant sediment is a clayey silt.The constituents of the bottom sediments fall into two groups: (1) particles of detrital or recycled rocks (limestone, quartz and clay minerals), and (2) crystals of minerals precipitated in surface waters (aragonite, gypsum, and halite).Aragonite concentrations are low in bottom sediments of the northern Dead Sea and increase southward. Gypsum occurs in bottom sediments from all water depths. This distribution shows that the rate of sulfate reduction does not keep pace with the rate of sulfate precipitation. Halite was found in the southern part of the northern basin.The areal distribution of primary minerals is a result of several processes. High concentrations reflect either periods of restricted circulation in certain areas, leading to massive precipitation, or high influx of saturated brines, leading to precipitation. By contrast, low concentrations reflect high input of detrital particles or periods of minor influx of highly saturated brine.The lack of large concentrations of evaporite minerals reflects: (1) the abundant supply of detrital particles being carried into the Dead Sea that lower the relative contribution of evaporite minerals; (2) dilution of surface waters by fresh water, and (3) the low values of HCO3− and SO4= in Dead Sea waters.

δ13C excursion in the end-proterozoic strata of the Vindhyan basin (Central India): Its chronostratigraphic significance

The Vindhyan basin of central peninsular India contains strata ranging in age from 1400 m.y. to 550 m.y. It is thus likely that the Precambrian-Cambrian boundary interval may be present in the upper part of the Vindhyan succession. In order to locate the boundary interval in the Vindhyan basin, carbon isotopic analyses of the carbonate horizons of the succession have been performed. The samples chosen for isotopic analysis were carefully selected after petrographic, cathodoluminesence and microelement studies to get the original isotopic signal. The analyses reveal that the carbonates of the lower part of the succession (middle Proterozoic) have δ13CPDB values close to zero (−1.1 to +0.9 permil). However, the carbon isotope profile of the uppermost part of the succession (Bhander and Sirbu Limestones) shows a positive shift of around 5 permil followed by a sharp drop in value to 2.7 permil. The isotope profile of this part of the Vindhyan succession is remarkably similar to those of well-established Precambrian-Cambrian boundary sections of the world. It thus seems that the Bhander and Sirbu Limestones may represent the Precambrian-Cambrian boundary interval in the Vindhyan basin. The carbon isotope chronostratigraphic marker for the Precambrian-Cambrian boundary interval has been identified in the Krol strata of the Himalayas, which were deposited in the late Precambrian-early Cambrian Tethys seaway. Of special significance to the present study is the fact that during this period the Vindhyan basin was also connected with the Tethys seaway.

The geological history of Messinian (upper miocene) evaporites in the Central Jordan Valley (Israel) and how strontium and sulfur isotopes relate to their origin

Evaporites, comprising gypsum, anhydrite, halite and dolomite are described from the Messinian Bira Formation outcrops and from two boreholes (Newe Ur-2 and Zemah-1) in the Central Jordan Valley, Israel. Strontium and sulfur isotopic compositions of the evaporite minerals, and their Sr/Ca and Br/Cl ratios are used to interpret their enviromments of deposition and processes of formation and diagenesis. The brines from which the evaporites precipitated originated from seawater. The processes caused by mixing of surface water, seawater and subsurface brines, resulted in dolomitization and also sulfur reduction. The surface water and subsurface brines reacted with the rocks they drained, including Cretaceous and Eocene carbonates and Neogene basalts. The gypsum deposits in the Central Jordan Valley are interpreted to have formed as a result of evaporation of the magnesium-rich Lake Bira water which became oversaturated with respect to calcite and gypsum. The gypsum was deposited in stratified, relatively closed basins, where a partial reduction of the sulfur resulted in high δ34S of the precipitated gypsum. Gypsum and early diagenetic dolomite formed from the same water bodies. The Bira evaporites in Newe Ur-2 borehole, precipitated from mixtures of sea- and fresh waters with basaltic contribution. The samples from the Lower Gabbro and Halite Unit in the Zemah-1 borehole were deposited from evaporated seawater, which leached basaltic rocks, in closed basins; the Middle Halite Unit formed from seawater, whiles the brines that deposited the Upper Halite Unit leached also basalt rocks.

The arid peritidal complex of Abu Dhabi: A historical perspective

This historical account relates to the work of the Research Committee of the American Association of Petroleum Geologists (AAPG) and two of its subcommittees: the Carbonate Rock Committee and the Persian Gulf Research Committee. In 1968–1970, as a member of the AAPG Research Committees and chair of the two other committees I was involved in supervising research in Abu Dhabi. The purpose of this paper is to document by aerial and ground photographs classical arid peritidal settings photographed in 1969 that are no longer pristine because the area of study in Abu Dhabi has suffered as a result of urban sprawl. This paper consists of a narrative for the photographs. The reader is encouraged to view the photographs and study their captions. They show peritidal settings, includingsabkhas, microbial mats, and supratidal anhydrite.

Diverse origin of modern dolomite in the Levant

The Dead-Sea transform in the Levant is a plate boundary that separates the Arabian from the Sinai plates. Along this transform modern dolomite occurs insabkhas, sea-marginal ponds, deep-sea settings, and non-marine saline springs. The non-marine dolomite from saline springs is of hydrothermal origin. Thesabkha and deep-sea dolomite are detrital and recycled from Cretaceous bedrock. The dolomite in sea-marginal ponds owes its origin to salinity-elevated seawaters and is an evaporite mineral. On the Sinai plate dolomite formed through the methane pathway, and west of the transform dolomite formed in caves from fresh-water effluent. Hence in one single geologic province modern dolomite is of multiple origins

Carbonate storm deposits (Tempestites) of Middle to Upper Cambrian age in the Helan Mountains, northwest China

Storm-influenced shelf carbonate deposits are well developed in the Middle to Upper Cambrian of the Helan Mountains, northwest China. The storm-influenced sequences can be divided into four major kinds of facies based on their lithologic and petrographic characteristics. They are: 1) supra-intertidal stromatolite-tempestite association, 2) barrier skeletal-oolitic tempestite association, 3) upper shelf proximal micrite-tempestite association, and 4) lower or distal shelf shale-micrite tempestite association. Lithofacies changes and tempestite relationships indicate that the shelf deepened to the south. Vertical frequencies in the sequence of storm deposits display cyclic changes on different orders. These cycles and cyclic orders reflect distinct episodic storm events.

Upper Cambrian-Lower Ordovician (Sauk) platform carbonates of the northern Appalachian (Gondwana) passive margin

Sauk platform carbonates of the northern Appalachian passive (Gondwana) margin are composed of high-frequency stacking patterns containing fifth-order depositional cycles. Most of the these cycles, termed parasequences in this study, display upward-shoaling peritidal patterns, commonly terminating in emergence. Parasequence surfaces are erosional resulting from this emergence and have associated karst features, especially solution-collapse breaccia. The carbonates, mostly fine- to medium-crystalline and locally vuggy dolostones, are generally of low permeability. Solution-collapse breccias increase whole-rock permeability through fractures. In addition to solution-collapse breccias, emergence generated terra-rossa soil, now lithified, as well as silcrete, now chert, and caused the dedolomitization of dolostones.Upward-coarsening facies cycles, in which flat-pebble conglomerates overlie erosional surfaces, are thought to be storm generated. Yet storm deposits with intraclasts sufficiently angular to be termed breccia may also terminate parasequences.Fifth-order upward-shoaling peritidal parasequences may be the result of extraterrestrial forcing or tectonic events causing rapid eustatic or relative changes in sea-level, respectively. Hence porosity-permeability development may likewise relate to these mechanisms. During the Sauk interval anomalous storm periods may have held sway on a global scale and generated upward-coarsening parasequences. Storm-weather periods probably resulted from astronomical changes (extraterrestrial forcing). Porosity and permeability in the storm deposits may also be controlled by extraterrestrial forcing functions.